'use strict';

var bbox = require('@turf/bbox');
var area = require('@turf/area');
var booleanPointInPolygon = require('@turf/boolean-point-in-polygon');
var explode = require('@turf/explode');
var invariant = require('@turf/invariant');
var helpers = require('@turf/helpers');
var objectAssign = require('object-assign');
var meta = require('@turf/meta');

function _interopDefaultLegacy (e) { return e && typeof e === 'object' && 'default' in e ? e : { 'default': e }; }

var bbox__default = /*#__PURE__*/_interopDefaultLegacy(bbox);
var area__default = /*#__PURE__*/_interopDefaultLegacy(area);
var booleanPointInPolygon__default = /*#__PURE__*/_interopDefaultLegacy(booleanPointInPolygon);
var explode__default = /*#__PURE__*/_interopDefaultLegacy(explode);
var objectAssign__default = /*#__PURE__*/_interopDefaultLegacy(objectAssign);

/**
 * Takes a {@link Point} grid and returns a correspondent matrix {Array<Array<number>>}
 * of the 'property' values
 *
 * @name gridToMatrix
 * @param {FeatureCollection<Point>} grid of points
 * @param {Object} [options={}] Optional parameters
 * @param {string} [options.zProperty='elevation'] the property name in `points` from which z-values will be pulled
 * @param {boolean} [options.flip=false] returns the matrix upside-down
 * @param {boolean} [options.flags=false] flags, adding a `matrixPosition` array field ([row, column]) to its properties,
 * the grid points with coordinates on the matrix
 * @returns {Array<Array<number>>} matrix of property values
 * @example
 *   var extent = [-70.823364, -33.553984, -70.473175, -33.302986];
 *   var cellSize = 3;
 *   var grid = turf.pointGrid(extent, cellSize);
 *   // add a random property to each point between 0 and 60
 *   for (var i = 0; i < grid.features.length; i++) {
 *     grid.features[i].properties.elevation = (Math.random() * 60);
 *   }
 *   gridToMatrix(grid);
 *   //= [
 *     [ 1, 13, 10,  9, 10, 13, 18],
 *     [34,  8,  5,  4,  5,  8, 13],
 *     [10,  5,  2,  1,  2,  5,  4],
 *     [ 0,  4, 56, 19,  1,  4,  9],
 *     [10,  5,  2,  1,  2,  5, 10],
 *     [57,  8,  5,  4,  5,  0, 57],
 *     [ 3, 13, 10,  9,  5, 13, 18],
 *     [18, 13, 10,  9, 78, 13, 18]
 *   ]
 */
function gridToMatrix(grid, options) {
  // Optional parameters
  options = options || {};
  if (!helpers.isObject(options)) throw new Error("options is invalid");
  var zProperty = options.zProperty || "elevation";
  var flip = options.flip;
  var flags = options.flags;

  // validation
  invariant.collectionOf(grid, "Point", "input must contain Points");

  var pointsMatrix = sortPointsByLatLng(grid, flip);

  var matrix = [];
  // create property matrix from sorted points
  // looping order matters here
  for (var r = 0; r < pointsMatrix.length; r++) {
    var pointRow = pointsMatrix[r];
    var row = [];
    for (var c = 0; c < pointRow.length; c++) {
      var point = pointRow[c];
      // Check if zProperty exist
      if (point.properties[zProperty]) row.push(point.properties[zProperty]);
      else row.push(0);
      // add flags
      if (flags === true) point.properties.matrixPosition = [r, c];
    }
    matrix.push(row);
  }

  return matrix;
}

/**
 * Sorts points by latitude and longitude, creating a 2-dimensional array of points
 *
 * @private
 * @param {FeatureCollection<Point>} points GeoJSON Point features
 * @param {boolean} [flip=false] returns the matrix upside-down
 * @returns {Array<Array<Point>>} points ordered by latitude and longitude
 */
function sortPointsByLatLng(points, flip) {
  var pointsByLatitude = {};

  // divide points by rows with the same latitude
  meta.featureEach(points, function (point) {
    var lat = invariant.getCoords(point)[1];
    if (!pointsByLatitude[lat]) pointsByLatitude[lat] = [];
    pointsByLatitude[lat].push(point);
  });

  // sort points (with the same latitude) by longitude
  var orderedRowsByLatitude = Object.keys(pointsByLatitude).map(function (lat) {
    var row = pointsByLatitude[lat];
    var rowOrderedByLongitude = row.sort(function (a, b) {
      return invariant.getCoords(a)[0] - invariant.getCoords(b)[0];
    });
    return rowOrderedByLongitude;
  });

  // sort rows (of points with the same latitude) by latitude
  var pointMatrix = orderedRowsByLatitude.sort(function (a, b) {
    if (flip) return invariant.getCoords(a[0])[1] - invariant.getCoords(b[0])[1];
    else return invariant.getCoords(b[0])[1] - invariant.getCoords(a[0])[1];
  });

  return pointMatrix;
}

/*!
 * @license GNU Affero General Public License.
 * Copyright (c) 2015, 2015 Ronny Lorenz <ronny@tbi.univie.ac.at>
 * v. 1.2.0
 * https://github.com/RaumZeit/MarchingSquares.js
 *
 * MarchingSquaresJS is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * MarchingSquaresJS is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * As additional permission under GNU Affero General Public License version 3
 * section 7, third-party projects (personal or commercial) may distribute,
 * include, or link against UNMODIFIED VERSIONS of MarchingSquaresJS without the
 * requirement that said third-party project for that reason alone becomes
 * subject to any requirement of the GNU Affero General Public License version 3.
 * Any modifications to MarchingSquaresJS, however, must be shared with the public
 * and made available.
 *
 * In summary this:
 * - allows you to use MarchingSquaresJS at no cost
 * - allows you to use MarchingSquaresJS for both personal and commercial purposes
 * - allows you to distribute UNMODIFIED VERSIONS of MarchingSquaresJS under any
 *   license as long as this license notice is included
 * - enables you to keep the source code of your program that uses MarchingSquaresJS
 *   undisclosed
 * - forces you to share any modifications you have made to MarchingSquaresJS,
 *   e.g. bug-fixes
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with MarchingSquaresJS.  If not, see <http://www.gnu.org/licenses/>.
 */
var defaultSettings = {
  successCallback: null,
  verbose: false,
  polygons: false,
};

var settings = {};

/*
  Compute isobands(s) of a scalar 2D field given a certain
  threshold and a bandwidth by applying the Marching Squares
  Algorithm. The function returns a list of path coordinates
  either for individual polygons within each grid cell, or the
  outline of connected polygons.
*/
function isoBands(data, minV, bandwidth, options) {
  /* process options */
  options = options ? options : {};

  var optionKeys = Object.keys(defaultSettings);

  for (var i = 0; i < optionKeys.length; i++) {
    var key = optionKeys[i];
    var val = options[key];
    val =
      typeof val !== "undefined" && val !== null ? val : defaultSettings[key];

    settings[key] = val;
  }

  if (settings.verbose)
    console.log(
      "MarchingSquaresJS-isoBands: computing isobands for [" +
        minV +
        ":" +
        (minV + bandwidth) +
        "]"
    );

  var grid = computeBandGrid(data, minV, bandwidth);

  var ret;
  if (settings.polygons) {
    if (settings.verbose)
      console.log(
        "MarchingSquaresJS-isoBands: returning single polygons for each grid cell"
      );
    ret = BandGrid2Areas(grid);
  } else {
    if (settings.verbose)
      console.log(
        "MarchingSquaresJS-isoBands: returning polygon paths for entire data grid"
      );
    ret = BandGrid2AreaPaths(grid);
  }

  if (typeof settings.successCallback === "function")
    settings.successCallback(ret);

  return ret;
}

/*
  Thats all for the public interface, below follows the actual
  implementation
*/

/* Some private variables */
var Node0 = 64,
  Node1 = 16,
  Node2 = 4,
  Node3 = 1;

/*
  The look-up tables for tracing back the contour path
  of isoBands
*/

var isoBandNextXTL = [];
var isoBandNextYTL = [];
var isoBandNextOTL = [];

var isoBandNextXTR = [];
var isoBandNextYTR = [];
var isoBandNextOTR = [];

var isoBandNextXRT = [];
var isoBandNextYRT = [];
var isoBandNextORT = [];

var isoBandNextXRB = [];
var isoBandNextYRB = [];
var isoBandNextORB = [];

var isoBandNextXBL = [];
var isoBandNextYBL = [];
var isoBandNextOBL = [];

var isoBandNextXBR = [];
var isoBandNextYBR = [];
var isoBandNextOBR = [];

var isoBandNextXLT = [];
var isoBandNextYLT = [];
var isoBandNextOLT = [];

var isoBandNextXLB = [];
var isoBandNextYLB = [];
var isoBandNextOLB = [];

isoBandNextXRT[85] = isoBandNextXRB[85] = -1;
isoBandNextYRT[85] = isoBandNextYRB[85] = 0;
isoBandNextORT[85] = isoBandNextORB[85] = 1;
isoBandNextXLT[85] = isoBandNextXLB[85] = 1;
isoBandNextYLT[85] = isoBandNextYLB[85] = 0;
isoBandNextOLT[85] = isoBandNextOLB[85] = 1;

isoBandNextXTL[85] = isoBandNextXTR[85] = 0;
isoBandNextYTL[85] = isoBandNextYTR[85] = -1;
isoBandNextOTL[85] = isoBandNextOBL[85] = 0;
isoBandNextXBR[85] = isoBandNextXBL[85] = 0;
isoBandNextYBR[85] = isoBandNextYBL[85] = 1;
isoBandNextOTR[85] = isoBandNextOBR[85] = 1;

/* triangle cases */
isoBandNextXLB[1] = isoBandNextXLB[169] = 0;
isoBandNextYLB[1] = isoBandNextYLB[169] = -1;
isoBandNextOLB[1] = isoBandNextOLB[169] = 0;
isoBandNextXBL[1] = isoBandNextXBL[169] = -1;
isoBandNextYBL[1] = isoBandNextYBL[169] = 0;
isoBandNextOBL[1] = isoBandNextOBL[169] = 0;

isoBandNextXRB[4] = isoBandNextXRB[166] = 0;
isoBandNextYRB[4] = isoBandNextYRB[166] = -1;
isoBandNextORB[4] = isoBandNextORB[166] = 1;
isoBandNextXBR[4] = isoBandNextXBR[166] = 1;
isoBandNextYBR[4] = isoBandNextYBR[166] = 0;
isoBandNextOBR[4] = isoBandNextOBR[166] = 0;

isoBandNextXRT[16] = isoBandNextXRT[154] = 0;
isoBandNextYRT[16] = isoBandNextYRT[154] = 1;
isoBandNextORT[16] = isoBandNextORT[154] = 1;
isoBandNextXTR[16] = isoBandNextXTR[154] = 1;
isoBandNextYTR[16] = isoBandNextYTR[154] = 0;
isoBandNextOTR[16] = isoBandNextOTR[154] = 1;

isoBandNextXLT[64] = isoBandNextXLT[106] = 0;
isoBandNextYLT[64] = isoBandNextYLT[106] = 1;
isoBandNextOLT[64] = isoBandNextOLT[106] = 0;
isoBandNextXTL[64] = isoBandNextXTL[106] = -1;
isoBandNextYTL[64] = isoBandNextYTL[106] = 0;
isoBandNextOTL[64] = isoBandNextOTL[106] = 1;

/* single trapezoid cases */
isoBandNextXLT[2] = isoBandNextXLT[168] = 0;
isoBandNextYLT[2] = isoBandNextYLT[168] = -1;
isoBandNextOLT[2] = isoBandNextOLT[168] = 1;
isoBandNextXLB[2] = isoBandNextXLB[168] = 0;
isoBandNextYLB[2] = isoBandNextYLB[168] = -1;
isoBandNextOLB[2] = isoBandNextOLB[168] = 0;
isoBandNextXBL[2] = isoBandNextXBL[168] = -1;
isoBandNextYBL[2] = isoBandNextYBL[168] = 0;
isoBandNextOBL[2] = isoBandNextOBL[168] = 0;
isoBandNextXBR[2] = isoBandNextXBR[168] = -1;
isoBandNextYBR[2] = isoBandNextYBR[168] = 0;
isoBandNextOBR[2] = isoBandNextOBR[168] = 1;

isoBandNextXRT[8] = isoBandNextXRT[162] = 0;
isoBandNextYRT[8] = isoBandNextYRT[162] = -1;
isoBandNextORT[8] = isoBandNextORT[162] = 0;
isoBandNextXRB[8] = isoBandNextXRB[162] = 0;
isoBandNextYRB[8] = isoBandNextYRB[162] = -1;
isoBandNextORB[8] = isoBandNextORB[162] = 1;
isoBandNextXBL[8] = isoBandNextXBL[162] = 1;
isoBandNextYBL[8] = isoBandNextYBL[162] = 0;
isoBandNextOBL[8] = isoBandNextOBL[162] = 1;
isoBandNextXBR[8] = isoBandNextXBR[162] = 1;
isoBandNextYBR[8] = isoBandNextYBR[162] = 0;
isoBandNextOBR[8] = isoBandNextOBR[162] = 0;

isoBandNextXRT[32] = isoBandNextXRT[138] = 0;
isoBandNextYRT[32] = isoBandNextYRT[138] = 1;
isoBandNextORT[32] = isoBandNextORT[138] = 1;
isoBandNextXRB[32] = isoBandNextXRB[138] = 0;
isoBandNextYRB[32] = isoBandNextYRB[138] = 1;
isoBandNextORB[32] = isoBandNextORB[138] = 0;
isoBandNextXTL[32] = isoBandNextXTL[138] = 1;
isoBandNextYTL[32] = isoBandNextYTL[138] = 0;
isoBandNextOTL[32] = isoBandNextOTL[138] = 0;
isoBandNextXTR[32] = isoBandNextXTR[138] = 1;
isoBandNextYTR[32] = isoBandNextYTR[138] = 0;
isoBandNextOTR[32] = isoBandNextOTR[138] = 1;

isoBandNextXLB[128] = isoBandNextXLB[42] = 0;
isoBandNextYLB[128] = isoBandNextYLB[42] = 1;
isoBandNextOLB[128] = isoBandNextOLB[42] = 1;
isoBandNextXLT[128] = isoBandNextXLT[42] = 0;
isoBandNextYLT[128] = isoBandNextYLT[42] = 1;
isoBandNextOLT[128] = isoBandNextOLT[42] = 0;
isoBandNextXTL[128] = isoBandNextXTL[42] = -1;
isoBandNextYTL[128] = isoBandNextYTL[42] = 0;
isoBandNextOTL[128] = isoBandNextOTL[42] = 1;
isoBandNextXTR[128] = isoBandNextXTR[42] = -1;
isoBandNextYTR[128] = isoBandNextYTR[42] = 0;
isoBandNextOTR[128] = isoBandNextOTR[42] = 0;

/* single rectangle cases */
isoBandNextXRB[5] = isoBandNextXRB[165] = -1;
isoBandNextYRB[5] = isoBandNextYRB[165] = 0;
isoBandNextORB[5] = isoBandNextORB[165] = 0;
isoBandNextXLB[5] = isoBandNextXLB[165] = 1;
isoBandNextYLB[5] = isoBandNextYLB[165] = 0;
isoBandNextOLB[5] = isoBandNextOLB[165] = 0;

isoBandNextXBR[20] = isoBandNextXBR[150] = 0;
isoBandNextYBR[20] = isoBandNextYBR[150] = 1;
isoBandNextOBR[20] = isoBandNextOBR[150] = 1;
isoBandNextXTR[20] = isoBandNextXTR[150] = 0;
isoBandNextYTR[20] = isoBandNextYTR[150] = -1;
isoBandNextOTR[20] = isoBandNextOTR[150] = 1;

isoBandNextXRT[80] = isoBandNextXRT[90] = -1;
isoBandNextYRT[80] = isoBandNextYRT[90] = 0;
isoBandNextORT[80] = isoBandNextORT[90] = 1;
isoBandNextXLT[80] = isoBandNextXLT[90] = 1;
isoBandNextYLT[80] = isoBandNextYLT[90] = 0;
isoBandNextOLT[80] = isoBandNextOLT[90] = 1;

isoBandNextXBL[65] = isoBandNextXBL[105] = 0;
isoBandNextYBL[65] = isoBandNextYBL[105] = 1;
isoBandNextOBL[65] = isoBandNextOBL[105] = 0;
isoBandNextXTL[65] = isoBandNextXTL[105] = 0;
isoBandNextYTL[65] = isoBandNextYTL[105] = -1;
isoBandNextOTL[65] = isoBandNextOTL[105] = 0;

isoBandNextXRT[160] = isoBandNextXRT[10] = -1;
isoBandNextYRT[160] = isoBandNextYRT[10] = 0;
isoBandNextORT[160] = isoBandNextORT[10] = 1;
isoBandNextXRB[160] = isoBandNextXRB[10] = -1;
isoBandNextYRB[160] = isoBandNextYRB[10] = 0;
isoBandNextORB[160] = isoBandNextORB[10] = 0;
isoBandNextXLB[160] = isoBandNextXLB[10] = 1;
isoBandNextYLB[160] = isoBandNextYLB[10] = 0;
isoBandNextOLB[160] = isoBandNextOLB[10] = 0;
isoBandNextXLT[160] = isoBandNextXLT[10] = 1;
isoBandNextYLT[160] = isoBandNextYLT[10] = 0;
isoBandNextOLT[160] = isoBandNextOLT[10] = 1;

isoBandNextXBR[130] = isoBandNextXBR[40] = 0;
isoBandNextYBR[130] = isoBandNextYBR[40] = 1;
isoBandNextOBR[130] = isoBandNextOBR[40] = 1;
isoBandNextXBL[130] = isoBandNextXBL[40] = 0;
isoBandNextYBL[130] = isoBandNextYBL[40] = 1;
isoBandNextOBL[130] = isoBandNextOBL[40] = 0;
isoBandNextXTL[130] = isoBandNextXTL[40] = 0;
isoBandNextYTL[130] = isoBandNextYTL[40] = -1;
isoBandNextOTL[130] = isoBandNextOTL[40] = 0;
isoBandNextXTR[130] = isoBandNextXTR[40] = 0;
isoBandNextYTR[130] = isoBandNextYTR[40] = -1;
isoBandNextOTR[130] = isoBandNextOTR[40] = 1;

/* single hexagon cases */
isoBandNextXRB[37] = isoBandNextXRB[133] = 0;
isoBandNextYRB[37] = isoBandNextYRB[133] = 1;
isoBandNextORB[37] = isoBandNextORB[133] = 1;
isoBandNextXLB[37] = isoBandNextXLB[133] = 0;
isoBandNextYLB[37] = isoBandNextYLB[133] = 1;
isoBandNextOLB[37] = isoBandNextOLB[133] = 0;
isoBandNextXTL[37] = isoBandNextXTL[133] = -1;
isoBandNextYTL[37] = isoBandNextYTL[133] = 0;
isoBandNextOTL[37] = isoBandNextOTL[133] = 0;
isoBandNextXTR[37] = isoBandNextXTR[133] = 1;
isoBandNextYTR[37] = isoBandNextYTR[133] = 0;
isoBandNextOTR[37] = isoBandNextOTR[133] = 0;

isoBandNextXBR[148] = isoBandNextXBR[22] = -1;
isoBandNextYBR[148] = isoBandNextYBR[22] = 0;
isoBandNextOBR[148] = isoBandNextOBR[22] = 0;
isoBandNextXLB[148] = isoBandNextXLB[22] = 0;
isoBandNextYLB[148] = isoBandNextYLB[22] = -1;
isoBandNextOLB[148] = isoBandNextOLB[22] = 1;
isoBandNextXLT[148] = isoBandNextXLT[22] = 0;
isoBandNextYLT[148] = isoBandNextYLT[22] = 1;
isoBandNextOLT[148] = isoBandNextOLT[22] = 1;
isoBandNextXTR[148] = isoBandNextXTR[22] = -1;
isoBandNextYTR[148] = isoBandNextYTR[22] = 0;
isoBandNextOTR[148] = isoBandNextOTR[22] = 1;

isoBandNextXRT[82] = isoBandNextXRT[88] = 0;
isoBandNextYRT[82] = isoBandNextYRT[88] = -1;
isoBandNextORT[82] = isoBandNextORT[88] = 1;
isoBandNextXBR[82] = isoBandNextXBR[88] = 1;
isoBandNextYBR[82] = isoBandNextYBR[88] = 0;
isoBandNextOBR[82] = isoBandNextOBR[88] = 1;
isoBandNextXBL[82] = isoBandNextXBL[88] = -1;
isoBandNextYBL[82] = isoBandNextYBL[88] = 0;
isoBandNextOBL[82] = isoBandNextOBL[88] = 1;
isoBandNextXLT[82] = isoBandNextXLT[88] = 0;
isoBandNextYLT[82] = isoBandNextYLT[88] = -1;
isoBandNextOLT[82] = isoBandNextOLT[88] = 0;

isoBandNextXRT[73] = isoBandNextXRT[97] = 0;
isoBandNextYRT[73] = isoBandNextYRT[97] = 1;
isoBandNextORT[73] = isoBandNextORT[97] = 0;
isoBandNextXRB[73] = isoBandNextXRB[97] = 0;
isoBandNextYRB[73] = isoBandNextYRB[97] = -1;
isoBandNextORB[73] = isoBandNextORB[97] = 0;
isoBandNextXBL[73] = isoBandNextXBL[97] = 1;
isoBandNextYBL[73] = isoBandNextYBL[97] = 0;
isoBandNextOBL[73] = isoBandNextOBL[97] = 0;
isoBandNextXTL[73] = isoBandNextXTL[97] = 1;
isoBandNextYTL[73] = isoBandNextYTL[97] = 0;
isoBandNextOTL[73] = isoBandNextOTL[97] = 1;

isoBandNextXRT[145] = isoBandNextXRT[25] = 0;
isoBandNextYRT[145] = isoBandNextYRT[25] = -1;
isoBandNextORT[145] = isoBandNextORT[25] = 0;
isoBandNextXBL[145] = isoBandNextXBL[25] = 1;
isoBandNextYBL[145] = isoBandNextYBL[25] = 0;
isoBandNextOBL[145] = isoBandNextOBL[25] = 1;
isoBandNextXLB[145] = isoBandNextXLB[25] = 0;
isoBandNextYLB[145] = isoBandNextYLB[25] = 1;
isoBandNextOLB[145] = isoBandNextOLB[25] = 1;
isoBandNextXTR[145] = isoBandNextXTR[25] = -1;
isoBandNextYTR[145] = isoBandNextYTR[25] = 0;
isoBandNextOTR[145] = isoBandNextOTR[25] = 0;

isoBandNextXRB[70] = isoBandNextXRB[100] = 0;
isoBandNextYRB[70] = isoBandNextYRB[100] = 1;
isoBandNextORB[70] = isoBandNextORB[100] = 0;
isoBandNextXBR[70] = isoBandNextXBR[100] = -1;
isoBandNextYBR[70] = isoBandNextYBR[100] = 0;
isoBandNextOBR[70] = isoBandNextOBR[100] = 1;
isoBandNextXLT[70] = isoBandNextXLT[100] = 0;
isoBandNextYLT[70] = isoBandNextYLT[100] = -1;
isoBandNextOLT[70] = isoBandNextOLT[100] = 1;
isoBandNextXTL[70] = isoBandNextXTL[100] = 1;
isoBandNextYTL[70] = isoBandNextYTL[100] = 0;
isoBandNextOTL[70] = isoBandNextOTL[100] = 0;

/* single pentagon cases */
isoBandNextXRB[101] = isoBandNextXRB[69] = 0;
isoBandNextYRB[101] = isoBandNextYRB[69] = 1;
isoBandNextORB[101] = isoBandNextORB[69] = 0;
isoBandNextXTL[101] = isoBandNextXTL[69] = 1;
isoBandNextYTL[101] = isoBandNextYTL[69] = 0;
isoBandNextOTL[101] = isoBandNextOTL[69] = 0;

isoBandNextXLB[149] = isoBandNextXLB[21] = 0;
isoBandNextYLB[149] = isoBandNextYLB[21] = 1;
isoBandNextOLB[149] = isoBandNextOLB[21] = 1;
isoBandNextXTR[149] = isoBandNextXTR[21] = -1;
isoBandNextYTR[149] = isoBandNextYTR[21] = 0;
isoBandNextOTR[149] = isoBandNextOTR[21] = 0;

isoBandNextXBR[86] = isoBandNextXBR[84] = -1;
isoBandNextYBR[86] = isoBandNextYBR[84] = 0;
isoBandNextOBR[86] = isoBandNextOBR[84] = 1;
isoBandNextXLT[86] = isoBandNextXLT[84] = 0;
isoBandNextYLT[86] = isoBandNextYLT[84] = -1;
isoBandNextOLT[86] = isoBandNextOLT[84] = 1;

isoBandNextXRT[89] = isoBandNextXRT[81] = 0;
isoBandNextYRT[89] = isoBandNextYRT[81] = -1;
isoBandNextORT[89] = isoBandNextORT[81] = 0;
isoBandNextXBL[89] = isoBandNextXBL[81] = 1;
isoBandNextYBL[89] = isoBandNextYBL[81] = 0;
isoBandNextOBL[89] = isoBandNextOBL[81] = 1;

isoBandNextXRT[96] = isoBandNextXRT[74] = 0;
isoBandNextYRT[96] = isoBandNextYRT[74] = 1;
isoBandNextORT[96] = isoBandNextORT[74] = 0;
isoBandNextXRB[96] = isoBandNextXRB[74] = -1;
isoBandNextYRB[96] = isoBandNextYRB[74] = 0;
isoBandNextORB[96] = isoBandNextORB[74] = 1;
isoBandNextXLT[96] = isoBandNextXLT[74] = 1;
isoBandNextYLT[96] = isoBandNextYLT[74] = 0;
isoBandNextOLT[96] = isoBandNextOLT[74] = 0;
isoBandNextXTL[96] = isoBandNextXTL[74] = 1;
isoBandNextYTL[96] = isoBandNextYTL[74] = 0;
isoBandNextOTL[96] = isoBandNextOTL[74] = 1;

isoBandNextXRT[24] = isoBandNextXRT[146] = 0;
isoBandNextYRT[24] = isoBandNextYRT[146] = -1;
isoBandNextORT[24] = isoBandNextORT[146] = 1;
isoBandNextXBR[24] = isoBandNextXBR[146] = 1;
isoBandNextYBR[24] = isoBandNextYBR[146] = 0;
isoBandNextOBR[24] = isoBandNextOBR[146] = 1;
isoBandNextXBL[24] = isoBandNextXBL[146] = 0;
isoBandNextYBL[24] = isoBandNextYBL[146] = 1;
isoBandNextOBL[24] = isoBandNextOBL[146] = 1;
isoBandNextXTR[24] = isoBandNextXTR[146] = 0;
isoBandNextYTR[24] = isoBandNextYTR[146] = -1;
isoBandNextOTR[24] = isoBandNextOTR[146] = 0;

isoBandNextXRB[6] = isoBandNextXRB[164] = -1;
isoBandNextYRB[6] = isoBandNextYRB[164] = 0;
isoBandNextORB[6] = isoBandNextORB[164] = 1;
isoBandNextXBR[6] = isoBandNextXBR[164] = -1;
isoBandNextYBR[6] = isoBandNextYBR[164] = 0;
isoBandNextOBR[6] = isoBandNextOBR[164] = 0;
isoBandNextXLB[6] = isoBandNextXLB[164] = 0;
isoBandNextYLB[6] = isoBandNextYLB[164] = -1;
isoBandNextOLB[6] = isoBandNextOLB[164] = 1;
isoBandNextXLT[6] = isoBandNextXLT[164] = 1;
isoBandNextYLT[6] = isoBandNextYLT[164] = 0;
isoBandNextOLT[6] = isoBandNextOLT[164] = 0;

isoBandNextXBL[129] = isoBandNextXBL[41] = 0;
isoBandNextYBL[129] = isoBandNextYBL[41] = 1;
isoBandNextOBL[129] = isoBandNextOBL[41] = 1;
isoBandNextXLB[129] = isoBandNextXLB[41] = 0;
isoBandNextYLB[129] = isoBandNextYLB[41] = 1;
isoBandNextOLB[129] = isoBandNextOLB[41] = 0;
isoBandNextXTL[129] = isoBandNextXTL[41] = -1;
isoBandNextYTL[129] = isoBandNextYTL[41] = 0;
isoBandNextOTL[129] = isoBandNextOTL[41] = 0;
isoBandNextXTR[129] = isoBandNextXTR[41] = 0;
isoBandNextYTR[129] = isoBandNextYTR[41] = -1;
isoBandNextOTR[129] = isoBandNextOTR[41] = 0;

isoBandNextXBR[66] = isoBandNextXBR[104] = 0;
isoBandNextYBR[66] = isoBandNextYBR[104] = 1;
isoBandNextOBR[66] = isoBandNextOBR[104] = 0;
isoBandNextXBL[66] = isoBandNextXBL[104] = -1;
isoBandNextYBL[66] = isoBandNextYBL[104] = 0;
isoBandNextOBL[66] = isoBandNextOBL[104] = 1;
isoBandNextXLT[66] = isoBandNextXLT[104] = 0;
isoBandNextYLT[66] = isoBandNextYLT[104] = -1;
isoBandNextOLT[66] = isoBandNextOLT[104] = 0;
isoBandNextXTL[66] = isoBandNextXTL[104] = 0;
isoBandNextYTL[66] = isoBandNextYTL[104] = -1;
isoBandNextOTL[66] = isoBandNextOTL[104] = 1;

isoBandNextXRT[144] = isoBandNextXRT[26] = -1;
isoBandNextYRT[144] = isoBandNextYRT[26] = 0;
isoBandNextORT[144] = isoBandNextORT[26] = 0;
isoBandNextXLB[144] = isoBandNextXLB[26] = 1;
isoBandNextYLB[144] = isoBandNextYLB[26] = 0;
isoBandNextOLB[144] = isoBandNextOLB[26] = 1;
isoBandNextXLT[144] = isoBandNextXLT[26] = 0;
isoBandNextYLT[144] = isoBandNextYLT[26] = 1;
isoBandNextOLT[144] = isoBandNextOLT[26] = 1;
isoBandNextXTR[144] = isoBandNextXTR[26] = -1;
isoBandNextYTR[144] = isoBandNextYTR[26] = 0;
isoBandNextOTR[144] = isoBandNextOTR[26] = 1;

isoBandNextXRB[36] = isoBandNextXRB[134] = 0;
isoBandNextYRB[36] = isoBandNextYRB[134] = 1;
isoBandNextORB[36] = isoBandNextORB[134] = 1;
isoBandNextXBR[36] = isoBandNextXBR[134] = 0;
isoBandNextYBR[36] = isoBandNextYBR[134] = 1;
isoBandNextOBR[36] = isoBandNextOBR[134] = 0;
isoBandNextXTL[36] = isoBandNextXTL[134] = 0;
isoBandNextYTL[36] = isoBandNextYTL[134] = -1;
isoBandNextOTL[36] = isoBandNextOTL[134] = 1;
isoBandNextXTR[36] = isoBandNextXTR[134] = 1;
isoBandNextYTR[36] = isoBandNextYTR[134] = 0;
isoBandNextOTR[36] = isoBandNextOTR[134] = 0;

isoBandNextXRT[9] = isoBandNextXRT[161] = -1;
isoBandNextYRT[9] = isoBandNextYRT[161] = 0;
isoBandNextORT[9] = isoBandNextORT[161] = 0;
isoBandNextXRB[9] = isoBandNextXRB[161] = 0;
isoBandNextYRB[9] = isoBandNextYRB[161] = -1;
isoBandNextORB[9] = isoBandNextORB[161] = 0;
isoBandNextXBL[9] = isoBandNextXBL[161] = 1;
isoBandNextYBL[9] = isoBandNextYBL[161] = 0;
isoBandNextOBL[9] = isoBandNextOBL[161] = 0;
isoBandNextXLB[9] = isoBandNextXLB[161] = 1;
isoBandNextYLB[9] = isoBandNextYLB[161] = 0;
isoBandNextOLB[9] = isoBandNextOLB[161] = 1;

/* 8-sided cases */
isoBandNextXRT[136] = 0;
isoBandNextYRT[136] = 1;
isoBandNextORT[136] = 1;
isoBandNextXRB[136] = 0;
isoBandNextYRB[136] = 1;
isoBandNextORB[136] = 0;
isoBandNextXBR[136] = -1;
isoBandNextYBR[136] = 0;
isoBandNextOBR[136] = 1;
isoBandNextXBL[136] = -1;
isoBandNextYBL[136] = 0;
isoBandNextOBL[136] = 0;
isoBandNextXLB[136] = 0;
isoBandNextYLB[136] = -1;
isoBandNextOLB[136] = 0;
isoBandNextXLT[136] = 0;
isoBandNextYLT[136] = -1;
isoBandNextOLT[136] = 1;
isoBandNextXTL[136] = 1;
isoBandNextYTL[136] = 0;
isoBandNextOTL[136] = 0;
isoBandNextXTR[136] = 1;
isoBandNextYTR[136] = 0;
isoBandNextOTR[136] = 1;

isoBandNextXRT[34] = 0;
isoBandNextYRT[34] = -1;
isoBandNextORT[34] = 0;
isoBandNextXRB[34] = 0;
isoBandNextYRB[34] = -1;
isoBandNextORB[34] = 1;
isoBandNextXBR[34] = 1;
isoBandNextYBR[34] = 0;
isoBandNextOBR[34] = 0;
isoBandNextXBL[34] = 1;
isoBandNextYBL[34] = 0;
isoBandNextOBL[34] = 1;
isoBandNextXLB[34] = 0;
isoBandNextYLB[34] = 1;
isoBandNextOLB[34] = 1;
isoBandNextXLT[34] = 0;
isoBandNextYLT[34] = 1;
isoBandNextOLT[34] = 0;
isoBandNextXTL[34] = -1;
isoBandNextYTL[34] = 0;
isoBandNextOTL[34] = 1;
isoBandNextXTR[34] = -1;
isoBandNextYTR[34] = 0;
isoBandNextOTR[34] = 0;

isoBandNextXRT[35] = 0;
isoBandNextYRT[35] = 1;
isoBandNextORT[35] = 1;
isoBandNextXRB[35] = 0;
isoBandNextYRB[35] = -1;
isoBandNextORB[35] = 1;
isoBandNextXBR[35] = 1;
isoBandNextYBR[35] = 0;
isoBandNextOBR[35] = 0;
isoBandNextXBL[35] = -1;
isoBandNextYBL[35] = 0;
isoBandNextOBL[35] = 0;
isoBandNextXLB[35] = 0;
isoBandNextYLB[35] = -1;
isoBandNextOLB[35] = 0;
isoBandNextXLT[35] = 0;
isoBandNextYLT[35] = 1;
isoBandNextOLT[35] = 0;
isoBandNextXTL[35] = -1;
isoBandNextYTL[35] = 0;
isoBandNextOTL[35] = 1;
isoBandNextXTR[35] = 1;
isoBandNextYTR[35] = 0;
isoBandNextOTR[35] = 1;

/* 6-sided cases */
isoBandNextXRT[153] = 0;
isoBandNextYRT[153] = 1;
isoBandNextORT[153] = 1;
isoBandNextXBL[153] = -1;
isoBandNextYBL[153] = 0;
isoBandNextOBL[153] = 0;
isoBandNextXLB[153] = 0;
isoBandNextYLB[153] = -1;
isoBandNextOLB[153] = 0;
isoBandNextXTR[153] = 1;
isoBandNextYTR[153] = 0;
isoBandNextOTR[153] = 1;

isoBandNextXRB[102] = 0;
isoBandNextYRB[102] = -1;
isoBandNextORB[102] = 1;
isoBandNextXBR[102] = 1;
isoBandNextYBR[102] = 0;
isoBandNextOBR[102] = 0;
isoBandNextXLT[102] = 0;
isoBandNextYLT[102] = 1;
isoBandNextOLT[102] = 0;
isoBandNextXTL[102] = -1;
isoBandNextYTL[102] = 0;
isoBandNextOTL[102] = 1;

isoBandNextXRT[155] = 0;
isoBandNextYRT[155] = -1;
isoBandNextORT[155] = 0;
isoBandNextXBL[155] = 1;
isoBandNextYBL[155] = 0;
isoBandNextOBL[155] = 1;
isoBandNextXLB[155] = 0;
isoBandNextYLB[155] = 1;
isoBandNextOLB[155] = 1;
isoBandNextXTR[155] = -1;
isoBandNextYTR[155] = 0;
isoBandNextOTR[155] = 0;

isoBandNextXRB[103] = 0;
isoBandNextYRB[103] = 1;
isoBandNextORB[103] = 0;
isoBandNextXBR[103] = -1;
isoBandNextYBR[103] = 0;
isoBandNextOBR[103] = 1;
isoBandNextXLT[103] = 0;
isoBandNextYLT[103] = -1;
isoBandNextOLT[103] = 1;
isoBandNextXTL[103] = 1;
isoBandNextYTL[103] = 0;
isoBandNextOTL[103] = 0;

/* 7-sided cases */
isoBandNextXRT[152] = 0;
isoBandNextYRT[152] = 1;
isoBandNextORT[152] = 1;
isoBandNextXBR[152] = -1;
isoBandNextYBR[152] = 0;
isoBandNextOBR[152] = 1;
isoBandNextXBL[152] = -1;
isoBandNextYBL[152] = 0;
isoBandNextOBL[152] = 0;
isoBandNextXLB[152] = 0;
isoBandNextYLB[152] = -1;
isoBandNextOLB[152] = 0;
isoBandNextXLT[152] = 0;
isoBandNextYLT[152] = -1;
isoBandNextOLT[152] = 1;
isoBandNextXTR[152] = 1;
isoBandNextYTR[152] = 0;
isoBandNextOTR[152] = 1;

isoBandNextXRT[156] = 0;
isoBandNextYRT[156] = -1;
isoBandNextORT[156] = 1;
isoBandNextXBR[156] = 1;
isoBandNextYBR[156] = 0;
isoBandNextOBR[156] = 1;
isoBandNextXBL[156] = -1;
isoBandNextYBL[156] = 0;
isoBandNextOBL[156] = 0;
isoBandNextXLB[156] = 0;
isoBandNextYLB[156] = -1;
isoBandNextOLB[156] = 0;
isoBandNextXLT[156] = 0;
isoBandNextYLT[156] = 1;
isoBandNextOLT[156] = 1;
isoBandNextXTR[156] = -1;
isoBandNextYTR[156] = 0;
isoBandNextOTR[156] = 1;

isoBandNextXRT[137] = 0;
isoBandNextYRT[137] = 1;
isoBandNextORT[137] = 1;
isoBandNextXRB[137] = 0;
isoBandNextYRB[137] = 1;
isoBandNextORB[137] = 0;
isoBandNextXBL[137] = -1;
isoBandNextYBL[137] = 0;
isoBandNextOBL[137] = 0;
isoBandNextXLB[137] = 0;
isoBandNextYLB[137] = -1;
isoBandNextOLB[137] = 0;
isoBandNextXTL[137] = 1;
isoBandNextYTL[137] = 0;
isoBandNextOTL[137] = 0;
isoBandNextXTR[137] = 1;
isoBandNextYTR[137] = 0;
isoBandNextOTR[137] = 1;

isoBandNextXRT[139] = 0;
isoBandNextYRT[139] = 1;
isoBandNextORT[139] = 1;
isoBandNextXRB[139] = 0;
isoBandNextYRB[139] = -1;
isoBandNextORB[139] = 0;
isoBandNextXBL[139] = 1;
isoBandNextYBL[139] = 0;
isoBandNextOBL[139] = 0;
isoBandNextXLB[139] = 0;
isoBandNextYLB[139] = 1;
isoBandNextOLB[139] = 0;
isoBandNextXTL[139] = -1;
isoBandNextYTL[139] = 0;
isoBandNextOTL[139] = 0;
isoBandNextXTR[139] = 1;
isoBandNextYTR[139] = 0;
isoBandNextOTR[139] = 1;

isoBandNextXRT[98] = 0;
isoBandNextYRT[98] = -1;
isoBandNextORT[98] = 0;
isoBandNextXRB[98] = 0;
isoBandNextYRB[98] = -1;
isoBandNextORB[98] = 1;
isoBandNextXBR[98] = 1;
isoBandNextYBR[98] = 0;
isoBandNextOBR[98] = 0;
isoBandNextXBL[98] = 1;
isoBandNextYBL[98] = 0;
isoBandNextOBL[98] = 1;
isoBandNextXLT[98] = 0;
isoBandNextYLT[98] = 1;
isoBandNextOLT[98] = 0;
isoBandNextXTL[98] = -1;
isoBandNextYTL[98] = 0;
isoBandNextOTL[98] = 1;

isoBandNextXRT[99] = 0;
isoBandNextYRT[99] = 1;
isoBandNextORT[99] = 0;
isoBandNextXRB[99] = 0;
isoBandNextYRB[99] = -1;
isoBandNextORB[99] = 1;
isoBandNextXBR[99] = 1;
isoBandNextYBR[99] = 0;
isoBandNextOBR[99] = 0;
isoBandNextXBL[99] = -1;
isoBandNextYBL[99] = 0;
isoBandNextOBL[99] = 1;
isoBandNextXLT[99] = 0;
isoBandNextYLT[99] = -1;
isoBandNextOLT[99] = 0;
isoBandNextXTL[99] = 1;
isoBandNextYTL[99] = 0;
isoBandNextOTL[99] = 1;

isoBandNextXRB[38] = 0;
isoBandNextYRB[38] = -1;
isoBandNextORB[38] = 1;
isoBandNextXBR[38] = 1;
isoBandNextYBR[38] = 0;
isoBandNextOBR[38] = 0;
isoBandNextXLB[38] = 0;
isoBandNextYLB[38] = 1;
isoBandNextOLB[38] = 1;
isoBandNextXLT[38] = 0;
isoBandNextYLT[38] = 1;
isoBandNextOLT[38] = 0;
isoBandNextXTL[38] = -1;
isoBandNextYTL[38] = 0;
isoBandNextOTL[38] = 1;
isoBandNextXTR[38] = -1;
isoBandNextYTR[38] = 0;
isoBandNextOTR[38] = 0;

isoBandNextXRB[39] = 0;
isoBandNextYRB[39] = 1;
isoBandNextORB[39] = 1;
isoBandNextXBR[39] = -1;
isoBandNextYBR[39] = 0;
isoBandNextOBR[39] = 0;
isoBandNextXLB[39] = 0;
isoBandNextYLB[39] = -1;
isoBandNextOLB[39] = 1;
isoBandNextXLT[39] = 0;
isoBandNextYLT[39] = 1;
isoBandNextOLT[39] = 0;
isoBandNextXTL[39] = -1;
isoBandNextYTL[39] = 0;
isoBandNextOTL[39] = 1;
isoBandNextXTR[39] = 1;
isoBandNextYTR[39] = 0;
isoBandNextOTR[39] = 0;

/*
  Define helper functions for the polygon_table
  */

/* triangle cases */
var p00 = function (cell) {
  return [
    [cell.bottomleft, 0],
    [0, 0],
    [0, cell.leftbottom],
  ];
};
var p01 = function (cell) {
  return [
    [1, cell.rightbottom],
    [1, 0],
    [cell.bottomright, 0],
  ];
};
var p02 = function (cell) {
  return [
    [cell.topright, 1],
    [1, 1],
    [1, cell.righttop],
  ];
};
var p03 = function (cell) {
  return [
    [0, cell.lefttop],
    [0, 1],
    [cell.topleft, 1],
  ];
};
/* trapezoid cases */
var p04 = function (cell) {
  return [
    [cell.bottomright, 0],
    [cell.bottomleft, 0],
    [0, cell.leftbottom],
    [0, cell.lefttop],
  ];
};
var p05 = function (cell) {
  return [
    [cell.bottomright, 0],
    [cell.bottomleft, 0],
    [1, cell.righttop],
    [1, cell.rightbottom],
  ];
};
var p06 = function (cell) {
  return [
    [1, cell.righttop],
    [1, cell.rightbottom],
    [cell.topleft, 1],
    [cell.topright, 1],
  ];
};
var p07 = function (cell) {
  return [
    [0, cell.leftbottom],
    [0, cell.lefttop],
    [cell.topleft, 1],
    [cell.topright, 1],
  ];
};
/* rectangle cases */
var p08 = function (cell) {
  return [
    [0, 0],
    [0, cell.leftbottom],
    [1, cell.rightbottom],
    [1, 0],
  ];
};
var p09 = function (cell) {
  return [
    [1, 0],
    [cell.bottomright, 0],
    [cell.topright, 1],
    [1, 1],
  ];
};
var p10 = function (cell) {
  return [
    [1, 1],
    [1, cell.righttop],
    [0, cell.lefttop],
    [0, 1],
  ];
};
var p11 = function (cell) {
  return [
    [cell.bottomleft, 0],
    [0, 0],
    [0, 1],
    [cell.topleft, 1],
  ];
};
var p12 = function (cell) {
  return [
    [1, cell.righttop],
    [1, cell.rightbottom],
    [0, cell.leftbottom],
    [0, cell.lefttop],
  ];
};
var p13 = function (cell) {
  return [
    [cell.topleft, 1],
    [cell.topright, 1],
    [cell.bottomright, 0],
    [cell.bottomleft, 0],
  ];
};
/* square case */
var p14 = function () {
  return [
    [0, 0],
    [0, 1],
    [1, 1],
    [1, 0],
  ];
};
/* pentagon cases */
var p15 = function (cell) {
  return [
    [1, cell.rightbottom],
    [1, 0],
    [0, 0],
    [0, 1],
    [cell.topleft, 1],
  ];
};
/* 1211 || 1011 */
var p16 = function (cell) {
  return [
    [cell.topright, 1],
    [1, 1],
    [1, 0],
    [0, 0],
    [0, cell.leftbottom],
  ];
};
/* 2111 || 0111 */
var p17 = function (cell) {
  return [
    [1, 0],
    [cell.bottomright, 0],
    [0, cell.lefttop],
    [0, 1],
    [1, 1],
  ];
};
/* 1112 || 1110 */
var p18 = function (cell) {
  return [
    [1, 1],
    [1, cell.righttop],
    [cell.bottomleft, 0],
    [0, 0],
    [0, 1],
  ];
};
/* 1121 || 1101 */
var p19 = function (cell) {
  return [
    [1, cell.righttop],
    [1, cell.rightbottom],
    [0, cell.lefttop],
    [0, 1],
    [cell.topleft, 1],
  ];
};
/* 1200 || 1022 */
var p20 = function (cell) {
  return [
    [1, 1],
    [1, cell.righttop],
    [cell.bottomright, 0],
    [cell.bottomleft, 0],
    [cell.topright, 1],
  ];
};
/* 0120 || 2102 */
var p21 = function (cell) {
  return [
    [1, cell.rightbottom],
    [1, 0],
    [cell.bottomright, 0],
    [0, cell.leftbottom],
    [0, cell.lefttop],
  ];
};
/* 0012 || 2210 */
var p22 = function (cell) {
  return [
    [cell.topright, 1],
    [cell.bottomleft, 0],
    [0, 0],
    [0, cell.leftbottom],
    [cell.topleft, 1],
  ];
};
/* 2001 || 0221 */
var p23 = function (cell) {
  return [
    [cell.bottomright, 0],
    [cell.bottomleft, 0],
    [0, cell.lefttop],
    [0, 1],
    [cell.topleft, 1],
  ];
};
/* 1002 || 1220 */
var p24 = function (cell) {
  return [
    [1, 1],
    [1, cell.righttop],
    [0, cell.leftbottom],
    [0, cell.lefttop],
    [cell.topright, 1],
  ];
};
/* 2100 || 0122 */
var p25 = function (cell) {
  return [
    [1, cell.rightbottom],
    [1, 0],
    [cell.bottomright, 0],
    [cell.topleft, 1],
    [cell.topright, 1],
  ];
};
/* 0210 || 2012 */
var p26 = function (cell) {
  return [
    [1, cell.righttop],
    [1, cell.rightbottom],
    [cell.bottomleft, 0],
    [0, 0],
    [0, cell.leftbottom],
  ];
};
/* 0021 || 2201 */
/*hexagon cases */
var p27 = function (cell) {
  return [
    [1, cell.rightbottom],
    [1, 0],
    [0, 0],
    [0, cell.leftbottom],
    [cell.topleft, 1],
    [cell.topright, 1],
  ];
};
/* 0211 || 2011 */
var p28 = function (cell) {
  return [
    [1, 1],
    [1, 0],
    [cell.bottomright, 0],
    [0, cell.leftbottom],
    [0, cell.lefttop],
    [cell.topright, 1],
  ];
};
/* 2110 || 0112 */
var p29 = function (cell) {
  return [
    [1, 1],
    [1, cell.righttop],
    [cell.bottomright, 0],
    [cell.bottomleft, 0],
    [0, cell.lefttop],
    [0, 1],
  ];
};
/* 1102 || 1120 */
var p30 = function (cell) {
  return [
    [1, cell.righttop],
    [1, cell.rightbottom],
    [cell.bottomleft, 0],
    [0, 0],
    [0, 1],
    [cell.topleft, 1],
  ];
};
/* 1021 || 1201 */
var p31 = function (cell) {
  return [
    [1, 1],
    [1, cell.righttop],
    [cell.bottomleft, 0],
    [0, 0],
    [0, cell.leftbottom],
    [cell.topright, 1],
  ];
};
/* 2101 || 0121 */
var p32 = function (cell) {
  return [
    [1, cell.rightbottom],
    [1, 0],
    [cell.bottomright, 0],
    [0, cell.lefttop],
    [0, 1],
    [cell.topleft, 1],
  ];
};
/* 1012 || 1210 */
/* 8-sided cases */
var p33 = function (cell) {
  return [
    [1, cell.righttop],
    [1, cell.rightbottom],
    [cell.bottomright, 0],
    [cell.bottomleft, 0],
    [0, cell.leftbottom],
    [0, cell.lefttop],
    [cell.topleft, 1],
    [cell.topright, 1],
  ];
};
/* flipped == 1 state for 0202 and 2020 */
/* 6-sided cases */
var p34 = function (cell) {
  return [
    [1, 1],
    [1, cell.righttop],
    [cell.bottomleft, 0],
    [0, 0],
    [0, cell.leftbottom],
    [cell.topright, 1],
  ];
};
/* 0101 with flipped == 1 || 2121 with flipped == 1 */
var p35 = function (cell) {
  return [
    [1, cell.rightbottom],
    [1, 0],
    [cell.bottomright, 0],
    [0, cell.lefttop],
    [0, 1],
    [cell.topleft, 1],
  ];
};
/* 1010 with flipped == 1 || 1212 with flipped == 1 */
/* 7-sided cases */
var p36 = function (cell) {
  return [
    [1, 1],
    [1, cell.righttop],
    [cell.bottomright, 0],
    [cell.bottomleft, 0],
    [0, cell.leftbottom],
    [0, cell.lefttop],
    [cell.topright, 1],
  ];
};
/* 2120 with flipped == 1 || 0102 with flipped == 1 */
var p37 = function (cell) {
  return [
    [1, cell.righttop],
    [1, cell.rightbottom],
    [cell.bottomleft, 0],
    [0, 0],
    [0, cell.leftbottom],
    [cell.topleft, 1],
    [cell.topright, 1],
  ];
};
/* 2021 with flipped == 1 || 0201 with flipped == 1 */
var p38 = function (cell) {
  return [
    [1, cell.righttop],
    [1, cell.rightbottom],
    [cell.bottomright, 0],
    [cell.bottomleft, 0],
    [0, cell.lefttop],
    [0, 1],
    [cell.topleft, 1],
  ];
};
/* 1202 with flipped == 1 || 1020 with flipped == 1 */
var p39 = function (cell) {
  return [
    [1, cell.rightbottom],
    [1, 0],
    [cell.bottomright, 0],
    [0, cell.leftbottom],
    [0, cell.lefttop],
    [cell.topleft, 1],
    [cell.topright, 1],
  ];
};
/* 0212 with flipped == 1 || 2010 with flipped == 1 */

/*
  The lookup tables for edge number given the polygon
  is entered at a specific location
*/

var isoBandEdgeRT = [];
var isoBandEdgeRB = [];
var isoBandEdgeBR = [];
var isoBandEdgeBL = [];
var isoBandEdgeLB = [];
var isoBandEdgeLT = [];
var isoBandEdgeTL = [];
var isoBandEdgeTR = [];

/* triangle cases */
isoBandEdgeBL[1] = isoBandEdgeLB[1] = 18;
isoBandEdgeBL[169] = isoBandEdgeLB[169] = 18;
isoBandEdgeBR[4] = isoBandEdgeRB[4] = 12;
isoBandEdgeBR[166] = isoBandEdgeRB[166] = 12;
isoBandEdgeRT[16] = isoBandEdgeTR[16] = 4;
isoBandEdgeRT[154] = isoBandEdgeTR[154] = 4;
isoBandEdgeLT[64] = isoBandEdgeTL[64] = 22;
isoBandEdgeLT[106] = isoBandEdgeTL[106] = 22;

/* trapezoid cases */
isoBandEdgeBR[2] = isoBandEdgeLT[2] = 17;
isoBandEdgeBL[2] = isoBandEdgeLB[2] = 18;
isoBandEdgeBR[168] = isoBandEdgeLT[168] = 17;
isoBandEdgeBL[168] = isoBandEdgeLB[168] = 18;
isoBandEdgeRT[8] = isoBandEdgeBL[8] = 9;
isoBandEdgeRB[8] = isoBandEdgeBR[8] = 12;
isoBandEdgeRT[162] = isoBandEdgeBL[162] = 9;
isoBandEdgeRB[162] = isoBandEdgeBR[162] = 12;
isoBandEdgeRT[32] = isoBandEdgeTR[32] = 4;
isoBandEdgeRB[32] = isoBandEdgeTL[32] = 1;
isoBandEdgeRT[138] = isoBandEdgeTR[138] = 4;
isoBandEdgeRB[138] = isoBandEdgeTL[138] = 1;
isoBandEdgeLB[128] = isoBandEdgeTR[128] = 21;
isoBandEdgeLT[128] = isoBandEdgeTL[128] = 22;
isoBandEdgeLB[42] = isoBandEdgeTR[42] = 21;
isoBandEdgeLT[42] = isoBandEdgeTL[42] = 22;

/* rectangle cases */
isoBandEdgeRB[5] = isoBandEdgeLB[5] = 14;
isoBandEdgeRB[165] = isoBandEdgeLB[165] = 14;
isoBandEdgeBR[20] = isoBandEdgeTR[20] = 6;
isoBandEdgeBR[150] = isoBandEdgeTR[150] = 6;
isoBandEdgeRT[80] = isoBandEdgeLT[80] = 11;
isoBandEdgeRT[90] = isoBandEdgeLT[90] = 11;
isoBandEdgeBL[65] = isoBandEdgeTL[65] = 3;
isoBandEdgeBL[105] = isoBandEdgeTL[105] = 3;
isoBandEdgeRT[160] = isoBandEdgeLT[160] = 11;
isoBandEdgeRB[160] = isoBandEdgeLB[160] = 14;
isoBandEdgeRT[10] = isoBandEdgeLT[10] = 11;
isoBandEdgeRB[10] = isoBandEdgeLB[10] = 14;
isoBandEdgeBR[130] = isoBandEdgeTR[130] = 6;
isoBandEdgeBL[130] = isoBandEdgeTL[130] = 3;
isoBandEdgeBR[40] = isoBandEdgeTR[40] = 6;
isoBandEdgeBL[40] = isoBandEdgeTL[40] = 3;

/* pentagon cases */
isoBandEdgeRB[101] = isoBandEdgeTL[101] = 1;
isoBandEdgeRB[69] = isoBandEdgeTL[69] = 1;
isoBandEdgeLB[149] = isoBandEdgeTR[149] = 21;
isoBandEdgeLB[21] = isoBandEdgeTR[21] = 21;
isoBandEdgeBR[86] = isoBandEdgeLT[86] = 17;
isoBandEdgeBR[84] = isoBandEdgeLT[84] = 17;
isoBandEdgeRT[89] = isoBandEdgeBL[89] = 9;
isoBandEdgeRT[81] = isoBandEdgeBL[81] = 9;
isoBandEdgeRT[96] = isoBandEdgeTL[96] = 0;
isoBandEdgeRB[96] = isoBandEdgeLT[96] = 15;
isoBandEdgeRT[74] = isoBandEdgeTL[74] = 0;
isoBandEdgeRB[74] = isoBandEdgeLT[74] = 15;
isoBandEdgeRT[24] = isoBandEdgeBR[24] = 8;
isoBandEdgeBL[24] = isoBandEdgeTR[24] = 7;
isoBandEdgeRT[146] = isoBandEdgeBR[146] = 8;
isoBandEdgeBL[146] = isoBandEdgeTR[146] = 7;
isoBandEdgeRB[6] = isoBandEdgeLT[6] = 15;
isoBandEdgeBR[6] = isoBandEdgeLB[6] = 16;
isoBandEdgeRB[164] = isoBandEdgeLT[164] = 15;
isoBandEdgeBR[164] = isoBandEdgeLB[164] = 16;
isoBandEdgeBL[129] = isoBandEdgeTR[129] = 7;
isoBandEdgeLB[129] = isoBandEdgeTL[129] = 20;
isoBandEdgeBL[41] = isoBandEdgeTR[41] = 7;
isoBandEdgeLB[41] = isoBandEdgeTL[41] = 20;
isoBandEdgeBR[66] = isoBandEdgeTL[66] = 2;
isoBandEdgeBL[66] = isoBandEdgeLT[66] = 19;
isoBandEdgeBR[104] = isoBandEdgeTL[104] = 2;
isoBandEdgeBL[104] = isoBandEdgeLT[104] = 19;
isoBandEdgeRT[144] = isoBandEdgeLB[144] = 10;
isoBandEdgeLT[144] = isoBandEdgeTR[144] = 23;
isoBandEdgeRT[26] = isoBandEdgeLB[26] = 10;
isoBandEdgeLT[26] = isoBandEdgeTR[26] = 23;
isoBandEdgeRB[36] = isoBandEdgeTR[36] = 5;
isoBandEdgeBR[36] = isoBandEdgeTL[36] = 2;
isoBandEdgeRB[134] = isoBandEdgeTR[134] = 5;
isoBandEdgeBR[134] = isoBandEdgeTL[134] = 2;
isoBandEdgeRT[9] = isoBandEdgeLB[9] = 10;
isoBandEdgeRB[9] = isoBandEdgeBL[9] = 13;
isoBandEdgeRT[161] = isoBandEdgeLB[161] = 10;
isoBandEdgeRB[161] = isoBandEdgeBL[161] = 13;

/* hexagon cases */
isoBandEdgeRB[37] = isoBandEdgeTR[37] = 5;
isoBandEdgeLB[37] = isoBandEdgeTL[37] = 20;
isoBandEdgeRB[133] = isoBandEdgeTR[133] = 5;
isoBandEdgeLB[133] = isoBandEdgeTL[133] = 20;
isoBandEdgeBR[148] = isoBandEdgeLB[148] = 16;
isoBandEdgeLT[148] = isoBandEdgeTR[148] = 23;
isoBandEdgeBR[22] = isoBandEdgeLB[22] = 16;
isoBandEdgeLT[22] = isoBandEdgeTR[22] = 23;
isoBandEdgeRT[82] = isoBandEdgeBR[82] = 8;
isoBandEdgeBL[82] = isoBandEdgeLT[82] = 19;
isoBandEdgeRT[88] = isoBandEdgeBR[88] = 8;
isoBandEdgeBL[88] = isoBandEdgeLT[88] = 19;
isoBandEdgeRT[73] = isoBandEdgeTL[73] = 0;
isoBandEdgeRB[73] = isoBandEdgeBL[73] = 13;
isoBandEdgeRT[97] = isoBandEdgeTL[97] = 0;
isoBandEdgeRB[97] = isoBandEdgeBL[97] = 13;
isoBandEdgeRT[145] = isoBandEdgeBL[145] = 9;
isoBandEdgeLB[145] = isoBandEdgeTR[145] = 21;
isoBandEdgeRT[25] = isoBandEdgeBL[25] = 9;
isoBandEdgeLB[25] = isoBandEdgeTR[25] = 21;
isoBandEdgeRB[70] = isoBandEdgeTL[70] = 1;
isoBandEdgeBR[70] = isoBandEdgeLT[70] = 17;
isoBandEdgeRB[100] = isoBandEdgeTL[100] = 1;
isoBandEdgeBR[100] = isoBandEdgeLT[100] = 17;

/* 8-sided cases */
isoBandEdgeRT[34] = isoBandEdgeBL[34] = 9;
isoBandEdgeRB[34] = isoBandEdgeBR[34] = 12;
isoBandEdgeLB[34] = isoBandEdgeTR[34] = 21;
isoBandEdgeLT[34] = isoBandEdgeTL[34] = 22;
isoBandEdgeRT[136] = isoBandEdgeTR[136] = 4;
isoBandEdgeRB[136] = isoBandEdgeTL[136] = 1;
isoBandEdgeBR[136] = isoBandEdgeLT[136] = 17;
isoBandEdgeBL[136] = isoBandEdgeLB[136] = 18;
isoBandEdgeRT[35] = isoBandEdgeTR[35] = 4;
isoBandEdgeRB[35] = isoBandEdgeBR[35] = 12;
isoBandEdgeBL[35] = isoBandEdgeLB[35] = 18;
isoBandEdgeLT[35] = isoBandEdgeTL[35] = 22;

/* 6-sided cases */
isoBandEdgeRT[153] = isoBandEdgeTR[153] = 4;
isoBandEdgeBL[153] = isoBandEdgeLB[153] = 18;
isoBandEdgeRB[102] = isoBandEdgeBR[102] = 12;
isoBandEdgeLT[102] = isoBandEdgeTL[102] = 22;
isoBandEdgeRT[155] = isoBandEdgeBL[155] = 9;
isoBandEdgeLB[155] = isoBandEdgeTR[155] = 23;
isoBandEdgeRB[103] = isoBandEdgeTL[103] = 1;
isoBandEdgeBR[103] = isoBandEdgeLT[103] = 17;

/* 7-sided cases */
isoBandEdgeRT[152] = isoBandEdgeTR[152] = 4;
isoBandEdgeBR[152] = isoBandEdgeLT[152] = 17;
isoBandEdgeBL[152] = isoBandEdgeLB[152] = 18;
isoBandEdgeRT[156] = isoBandEdgeBR[156] = 8;
isoBandEdgeBL[156] = isoBandEdgeLB[156] = 18;
isoBandEdgeLT[156] = isoBandEdgeTR[156] = 23;
isoBandEdgeRT[137] = isoBandEdgeTR[137] = 4;
isoBandEdgeRB[137] = isoBandEdgeTL[137] = 1;
isoBandEdgeBL[137] = isoBandEdgeLB[137] = 18;
isoBandEdgeRT[139] = isoBandEdgeTR[139] = 4;
isoBandEdgeRB[139] = isoBandEdgeBL[139] = 13;
isoBandEdgeLB[139] = isoBandEdgeTL[139] = 20;
isoBandEdgeRT[98] = isoBandEdgeBL[98] = 9;
isoBandEdgeRB[98] = isoBandEdgeBR[98] = 12;
isoBandEdgeLT[98] = isoBandEdgeTL[98] = 22;
isoBandEdgeRT[99] = isoBandEdgeTL[99] = 0;
isoBandEdgeRB[99] = isoBandEdgeBR[99] = 12;
isoBandEdgeBL[99] = isoBandEdgeLT[99] = 19;
isoBandEdgeRB[38] = isoBandEdgeBR[38] = 12;
isoBandEdgeLB[38] = isoBandEdgeTR[38] = 21;
isoBandEdgeLT[38] = isoBandEdgeTL[38] = 22;
isoBandEdgeRB[39] = isoBandEdgeTR[39] = 5;
isoBandEdgeBR[39] = isoBandEdgeLB[39] = 16;
isoBandEdgeLT[39] = isoBandEdgeTL[39] = 22;

/*
  The lookup tables for all different polygons that
  may appear within a grid cell
*/

var polygon_table = [];

/* triangle cases */
polygon_table[1] = polygon_table[169] = p00; /* 2221 || 0001 */
polygon_table[4] = polygon_table[166] = p01; /* 2212 || 0010 */
polygon_table[16] = polygon_table[154] = p02; /* 2122 || 0100 */
polygon_table[64] = polygon_table[106] = p03; /* 1222 || 1000 */

/* trapezoid cases */
polygon_table[168] = polygon_table[2] = p04; /* 2220 || 0002 */
polygon_table[162] = polygon_table[8] = p05; /* 2202 || 0020 */
polygon_table[138] = polygon_table[32] = p06; /* 2022 || 0200 */
polygon_table[42] = polygon_table[128] = p07; /* 0222 || 2000 */

/* rectangle cases */
polygon_table[5] = polygon_table[165] = p08; /* 0011 || 2211 */
polygon_table[20] = polygon_table[150] = p09; /* 0110 || 2112 */
polygon_table[80] = polygon_table[90] = p10; /* 1100 || 1122 */
polygon_table[65] = polygon_table[105] = p11; /* 1001 || 1221 */
polygon_table[160] = polygon_table[10] = p12; /* 2200 || 0022 */
polygon_table[130] = polygon_table[40] = p13; /* 2002 || 0220 */

/* square case */
polygon_table[85] = p14; /* 1111 */

/* pentagon cases */
polygon_table[101] = polygon_table[69] = p15; /* 1211 || 1011 */
polygon_table[149] = polygon_table[21] = p16; /* 2111 || 0111 */
polygon_table[86] = polygon_table[84] = p17; /* 1112 || 1110 */
polygon_table[89] = polygon_table[81] = p18; /* 1121 || 1101 */
polygon_table[96] = polygon_table[74] = p19; /* 1200 || 1022 */
polygon_table[24] = polygon_table[146] = p20; /* 0120 || 2102 */
polygon_table[6] = polygon_table[164] = p21; /* 0012 || 2210 */
polygon_table[129] = polygon_table[41] = p22; /* 2001 || 0221 */
polygon_table[66] = polygon_table[104] = p23; /* 1002 || 1220 */
polygon_table[144] = polygon_table[26] = p24; /* 2100 || 0122 */
polygon_table[36] = polygon_table[134] = p25; /* 0210 || 2012 */
polygon_table[9] = polygon_table[161] = p26; /* 0021 || 2201 */

/* hexagon cases */
polygon_table[37] = polygon_table[133] = p27; /* 0211 || 2011 */
polygon_table[148] = polygon_table[22] = p28; /* 2110 || 0112 */
polygon_table[82] = polygon_table[88] = p29; /* 1102 || 1120 */
polygon_table[73] = polygon_table[97] = p30; /* 1021 || 1201 */
polygon_table[145] = polygon_table[25] = p31; /* 2101 || 0121 */
polygon_table[70] = polygon_table[100] = p32; /* 1012 || 1210 */

/* 8-sided cases */
polygon_table[34] = function (c) {
  return [p07(c), p05(c)];
}; /* 0202 || 2020 with flipped == 0 */
polygon_table[35] = p33; /* flipped == 1 state for 0202 and 2020 */
polygon_table[136] = function (c) {
  return [p06(c), p04(c)];
}; /* 2020 || 0202 with flipped == 0 */

/* 6-sided cases */
polygon_table[153] = function (c) {
  return [p02(c), p00(c)];
}; /* 0101 with flipped == 0 || 2121 with flipped == 2 */
polygon_table[102] = function (c) {
  return [p01(c), p03(c)];
}; /* 1010 with flipped == 0 || 1212 with flipped == 2 */
polygon_table[155] = p34; /* 0101 with flipped == 1 || 2121 with flipped == 1 */
polygon_table[103] = p35; /* 1010 with flipped == 1 || 1212 with flipped == 1 */

/* 7-sided cases */
polygon_table[152] = function (c) {
  return [p02(c), p04(c)];
}; /* 2120 with flipped == 2 || 0102 with flipped == 0 */
polygon_table[156] = p36; /* 2120 with flipped == 1 || 0102 with flipped == 1 */
polygon_table[137] = function (c) {
  return [p06(c), p00(c)];
}; /* 2021 with flipped == 2 || 0201 with flipped == 0 */
polygon_table[139] = p37; /* 2021 with flipped == 1 || 0201 with flipped == 1 */
polygon_table[98] = function (c) {
  return [p05(c), p03(c)];
}; /* 1202 with flipped == 2 || 1020 with flipped == 0 */
polygon_table[99] = p38; /* 1202 with flipped == 1 || 1020 with flipped == 1 */
polygon_table[38] = function (c) {
  return [p01(c), p07(c)];
}; /* 0212 with flipped == 2 || 2010 with flipped == 0 */
polygon_table[39] = p39; /* 0212 with flipped == 1 || 2010 with flipped == 1 */

/*
####################################
Some small helper functions
####################################
*/

/* assume that x1 == 1 &&  x0 == 0 */
function interpolateX(y, y0, y1) {
  return (y - y0) / (y1 - y0);
}

function isArray(myArray) {
  return myArray.constructor.toString().indexOf("Array") > -1;
}

/*
####################################
Below is the actual Marching Squares implementation
####################################
*/

function computeBandGrid(data, minV, bandwidth) {
  var rows = data.length - 1;
  var cols = data[0].length - 1;
  var BandGrid = { rows: rows, cols: cols, cells: [] };

  var maxV = minV + Math.abs(bandwidth);

  for (var j = 0; j < rows; ++j) {
    BandGrid.cells[j] = [];
    for (var i = 0; i < cols; ++i) {
      /*  compose the 4-trit corner representation */
      var cval = 0;

      var tl = data[j + 1][i];
      var tr = data[j + 1][i + 1];
      var br = data[j][i + 1];
      var bl = data[j][i];

      if (isNaN(tl) || isNaN(tr) || isNaN(br) || isNaN(bl)) {
        continue;
      }

      cval |= tl < minV ? 0 : tl > maxV ? 128 : 64;
      cval |= tr < minV ? 0 : tr > maxV ? 32 : 16;
      cval |= br < minV ? 0 : br > maxV ? 8 : 4;
      cval |= bl < minV ? 0 : bl > maxV ? 2 : 1;

      var cval_real = +cval;

      /* resolve ambiguity via averaging */
      var flipped = 0;
      if (
        cval === 17 /* 0101 */ ||
        cval === 18 /* 0102 */ ||
        cval === 33 /* 0201 */ ||
        cval === 34 /* 0202 */ ||
        cval === 38 /* 0212 */ ||
        cval === 68 /* 1010 */ ||
        cval === 72 /* 1020 */ ||
        cval === 98 /* 1202 */ ||
        cval === 102 /* 1212 */ ||
        cval === 132 /* 2010 */ ||
        cval === 136 /* 2020 */ ||
        cval === 137 /* 2021 */ ||
        cval === 152 /* 2120 */ ||
        cval === 153 /* 2121 */
      ) {
        var average = (tl + tr + br + bl) / 4;
        /* set flipped state */
        flipped = average > maxV ? 2 : average < minV ? 0 : 1;

        /* adjust cval for flipped cases */

        /* 8-sided cases */
        if (cval === 34) {
          if (flipped === 1) {
            cval = 35;
          } else if (flipped === 0) {
            cval = 136;
          }
        } else if (cval === 136) {
          if (flipped === 1) {
            cval = 35;
            flipped = 4;
          } else if (flipped === 0) {
            cval = 34;
          }
        } else if (cval === 17) {
          /* 6-sided polygon cases */
          if (flipped === 1) {
            cval = 155;
            flipped = 4;
          } else if (flipped === 0) {
            cval = 153;
          }
        } else if (cval === 68) {
          if (flipped === 1) {
            cval = 103;
            flipped = 4;
          } else if (flipped === 0) {
            cval = 102;
          }
        } else if (cval === 153) {
          if (flipped === 1) cval = 155;
        } else if (cval === 102) {
          if (flipped === 1) cval = 103;
        } else if (cval === 152) {
          /* 7-sided polygon cases */
          if (flipped < 2) {
            cval = 156;
            flipped = 1;
          }
        } else if (cval === 137) {
          if (flipped < 2) {
            cval = 139;
            flipped = 1;
          }
        } else if (cval === 98) {
          if (flipped < 2) {
            cval = 99;
            flipped = 1;
          }
        } else if (cval === 38) {
          if (flipped < 2) {
            cval = 39;
            flipped = 1;
          }
        } else if (cval === 18) {
          if (flipped > 0) {
            cval = 156;
            flipped = 4;
          } else {
            cval = 152;
          }
        } else if (cval === 33) {
          if (flipped > 0) {
            cval = 139;
            flipped = 4;
          } else {
            cval = 137;
          }
        } else if (cval === 72) {
          if (flipped > 0) {
            cval = 99;
            flipped = 4;
          } else {
            cval = 98;
          }
        } else if (cval === 132) {
          if (flipped > 0) {
            cval = 39;
            flipped = 4;
          } else {
            cval = 38;
          }
        }
      }

      /* add cell to BandGrid if it contains at least one polygon-side */
      if (cval != 0 && cval != 170) {
        var topleft,
          topright,
          bottomleft,
          bottomright,
          righttop,
          rightbottom,
          lefttop,
          leftbottom;

        topleft = topright = bottomleft = bottomright = righttop = rightbottom = lefttop = leftbottom = 0.5;

        var edges = [];

        /* do interpolation here */
        /* 1st Triangles */
        if (cval === 1) {
          /* 0001 */
          bottomleft = 1 - interpolateX(minV, br, bl);
          leftbottom = 1 - interpolateX(minV, tl, bl);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 169) {
          /* 2221 */
          bottomleft = interpolateX(maxV, bl, br);
          leftbottom = interpolateX(maxV, bl, tl);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 4) {
          /* 0010 */
          rightbottom = 1 - interpolateX(minV, tr, br);
          bottomright = interpolateX(minV, bl, br);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 166) {
          /* 2212 */
          rightbottom = interpolateX(maxV, br, tr);
          bottomright = 1 - interpolateX(maxV, br, bl);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 16) {
          /* 0100 */
          righttop = interpolateX(minV, br, tr);
          topright = interpolateX(minV, tl, tr);
          edges.push(isoBandEdgeRT[cval]);
        } else if (cval === 154) {
          /* 2122 */
          righttop = 1 - interpolateX(maxV, tr, br);
          topright = 1 - interpolateX(maxV, tr, tl);
          edges.push(isoBandEdgeRT[cval]);
        } else if (cval === 64) {
          /* 1000 */
          lefttop = interpolateX(minV, bl, tl);
          topleft = 1 - interpolateX(minV, tr, tl);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 106) {
          /* 1222 */
          lefttop = 1 - interpolateX(maxV, tl, bl);
          topleft = interpolateX(maxV, tl, tr);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 168) {
          /* 2nd Trapezoids */
          /* 2220 */
          bottomright = interpolateX(maxV, bl, br);
          bottomleft = interpolateX(minV, bl, br);
          leftbottom = interpolateX(minV, bl, tl);
          lefttop = interpolateX(maxV, bl, tl);
          edges.push(isoBandEdgeBR[cval]);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 2) {
          /* 0002 */
          bottomright = 1 - interpolateX(minV, br, bl);
          bottomleft = 1 - interpolateX(maxV, br, bl);
          leftbottom = 1 - interpolateX(maxV, tl, bl);
          lefttop = 1 - interpolateX(minV, tl, bl);
          edges.push(isoBandEdgeBR[cval]);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 162) {
          /* 2202 */
          righttop = interpolateX(maxV, br, tr);
          rightbottom = interpolateX(minV, br, tr);
          bottomright = 1 - interpolateX(minV, br, bl);
          bottomleft = 1 - interpolateX(maxV, br, bl);
          edges.push(isoBandEdgeBR[cval]);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 8) {
          /* 0020 */
          righttop = 1 - interpolateX(minV, tr, br);
          rightbottom = 1 - interpolateX(maxV, tr, br);
          bottomright = interpolateX(maxV, bl, br);
          bottomleft = interpolateX(minV, bl, br);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 138) {
          /* 2022 */
          righttop = 1 - interpolateX(minV, tr, br);
          rightbottom = 1 - interpolateX(maxV, tr, br);
          topleft = 1 - interpolateX(maxV, tr, tl);
          topright = 1 - interpolateX(minV, tr, tl);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 32) {
          /* 0200 */
          righttop = interpolateX(maxV, br, tr);
          rightbottom = interpolateX(minV, br, tr);
          topleft = interpolateX(minV, tl, tr);
          topright = interpolateX(maxV, tl, tr);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 42) {
          /* 0222 */
          leftbottom = 1 - interpolateX(maxV, tl, bl);
          lefttop = 1 - interpolateX(minV, tl, bl);
          topleft = interpolateX(minV, tl, tr);
          topright = interpolateX(maxV, tl, tr);
          edges.push(isoBandEdgeLB[cval]);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 128) {
          /* 2000 */
          leftbottom = interpolateX(minV, bl, tl);
          lefttop = interpolateX(maxV, bl, tl);
          topleft = 1 - interpolateX(maxV, tr, tl);
          topright = 1 - interpolateX(minV, tr, tl);
          edges.push(isoBandEdgeLB[cval]);
          edges.push(isoBandEdgeLT[cval]);
        }

        /* 3rd rectangle cases */
        if (cval === 5) {
          /* 0011 */
          rightbottom = 1 - interpolateX(minV, tr, br);
          leftbottom = 1 - interpolateX(minV, tl, bl);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 165) {
          /* 2211 */
          rightbottom = interpolateX(maxV, br, tr);
          leftbottom = interpolateX(maxV, bl, tl);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 20) {
          /* 0110 */
          bottomright = interpolateX(minV, bl, br);
          topright = interpolateX(minV, tl, tr);
          edges.push(isoBandEdgeBR[cval]);
        } else if (cval === 150) {
          /* 2112 */
          bottomright = 1 - interpolateX(maxV, br, bl);
          topright = 1 - interpolateX(maxV, tr, tl);
          edges.push(isoBandEdgeBR[cval]);
        } else if (cval === 80) {
          /* 1100 */
          righttop = interpolateX(minV, br, tr);
          lefttop = interpolateX(minV, bl, tl);
          edges.push(isoBandEdgeRT[cval]);
        } else if (cval === 90) {
          /* 1122 */
          righttop = 1 - interpolateX(maxV, tr, br);
          lefttop = 1 - interpolateX(maxV, tl, bl);
          edges.push(isoBandEdgeRT[cval]);
        } else if (cval === 65) {
          /* 1001 */
          bottomleft = 1 - interpolateX(minV, br, bl);
          topleft = 1 - interpolateX(minV, tr, tl);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 105) {
          /* 1221 */
          bottomleft = interpolateX(maxV, bl, br);
          topleft = interpolateX(maxV, tl, tr);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 160) {
          /* 2200 */
          righttop = interpolateX(maxV, br, tr);
          rightbottom = interpolateX(minV, br, tr);
          leftbottom = interpolateX(minV, bl, tl);
          lefttop = interpolateX(maxV, bl, tl);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 10) {
          /* 0022 */
          righttop = 1 - interpolateX(minV, tr, br);
          rightbottom = 1 - interpolateX(maxV, tr, br);
          leftbottom = 1 - interpolateX(maxV, tl, bl);
          lefttop = 1 - interpolateX(minV, tl, bl);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 130) {
          /* 2002 */
          bottomright = 1 - interpolateX(minV, br, bl);
          bottomleft = 1 - interpolateX(maxV, br, bl);
          topleft = 1 - interpolateX(maxV, tr, tl);
          topright = 1 - interpolateX(minV, tr, tl);
          edges.push(isoBandEdgeBR[cval]);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 40) {
          /* 0220 */
          bottomright = interpolateX(maxV, bl, br);
          bottomleft = interpolateX(minV, bl, br);
          topleft = interpolateX(minV, tl, tr);
          topright = interpolateX(maxV, tl, tr);
          edges.push(isoBandEdgeBR[cval]);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 101) {
          /* 4th single pentagon cases */
          /* 1211 */
          rightbottom = interpolateX(maxV, br, tr);
          topleft = interpolateX(maxV, tl, tr);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 69) {
          /* 1011 */
          rightbottom = 1 - interpolateX(minV, tr, br);
          topleft = 1 - interpolateX(minV, tr, tl);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 149) {
          /* 2111 */
          leftbottom = interpolateX(maxV, bl, tl);
          topright = 1 - interpolateX(maxV, tr, tl);
          edges.push(isoBandEdgeLB[cval]);
        } else if (cval === 21) {
          /* 0111 */
          leftbottom = 1 - interpolateX(minV, tl, bl);
          topright = interpolateX(minV, tl, tr);
          edges.push(isoBandEdgeLB[cval]);
        } else if (cval === 86) {
          /* 1112 */
          bottomright = 1 - interpolateX(maxV, br, bl);
          lefttop = 1 - interpolateX(maxV, tl, bl);
          edges.push(isoBandEdgeBR[cval]);
        } else if (cval === 84) {
          /* 1110 */
          bottomright = interpolateX(minV, bl, br);
          lefttop = interpolateX(minV, bl, tl);
          edges.push(isoBandEdgeBR[cval]);
        } else if (cval === 89) {
          /* 1121 */
          righttop = 1 - interpolateX(maxV, tr, br);
          bottomleft = interpolateX(maxV, bl, br);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 81) {
          /* 1101 */
          righttop = interpolateX(minV, br, tr);
          bottomleft = 1 - interpolateX(minV, br, bl);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 96) {
          /* 1200 */
          righttop = interpolateX(maxV, br, tr);
          rightbottom = interpolateX(minV, br, tr);
          lefttop = interpolateX(minV, bl, tl);
          topleft = interpolateX(maxV, tl, tr);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 74) {
          /* 1022 */
          righttop = 1 - interpolateX(minV, tr, br);
          rightbottom = 1 - interpolateX(maxV, tr, br);
          lefttop = 1 - interpolateX(maxV, tl, bl);
          topleft = 1 - interpolateX(minV, tr, tl);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 24) {
          /* 0120 */
          righttop = 1 - interpolateX(maxV, tr, br);
          bottomright = interpolateX(maxV, bl, br);
          bottomleft = interpolateX(minV, bl, br);
          topright = interpolateX(minV, tl, tr);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 146) {
          /* 2102 */
          righttop = interpolateX(minV, br, tr);
          bottomright = 1 - interpolateX(minV, br, bl);
          bottomleft = 1 - interpolateX(maxV, br, bl);
          topright = 1 - interpolateX(maxV, tr, tl);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 6) {
          /* 0012 */
          rightbottom = 1 - interpolateX(minV, tr, br);
          bottomright = 1 - interpolateX(maxV, br, bl);
          leftbottom = 1 - interpolateX(maxV, tl, bl);
          lefttop = 1 - interpolateX(minV, tl, bl);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeBR[cval]);
        } else if (cval === 164) {
          /* 2210 */
          rightbottom = interpolateX(maxV, br, tr);
          bottomright = interpolateX(minV, bl, br);
          leftbottom = interpolateX(minV, bl, tl);
          lefttop = interpolateX(maxV, bl, tl);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeBR[cval]);
        } else if (cval === 129) {
          /* 2001 */
          bottomleft = 1 - interpolateX(minV, br, bl);
          leftbottom = interpolateX(maxV, bl, tl);
          topleft = 1 - interpolateX(maxV, tr, tl);
          topright = 1 - interpolateX(minV, tr, tl);
          edges.push(isoBandEdgeBL[cval]);
          edges.push(isoBandEdgeLB[cval]);
        } else if (cval === 41) {
          /* 0221 */
          bottomleft = interpolateX(maxV, bl, br);
          leftbottom = 1 - interpolateX(minV, tl, bl);
          topleft = interpolateX(minV, tl, tr);
          topright = interpolateX(maxV, tl, tr);
          edges.push(isoBandEdgeBL[cval]);
          edges.push(isoBandEdgeLB[cval]);
        } else if (cval === 66) {
          /* 1002 */
          bottomright = 1 - interpolateX(minV, br, bl);
          bottomleft = 1 - interpolateX(maxV, br, bl);
          lefttop = 1 - interpolateX(maxV, tl, bl);
          topleft = 1 - interpolateX(minV, tr, tl);
          edges.push(isoBandEdgeBR[cval]);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 104) {
          /* 1220 */
          bottomright = interpolateX(maxV, bl, br);
          bottomleft = interpolateX(minV, bl, br);
          lefttop = interpolateX(minV, bl, tl);
          topleft = interpolateX(maxV, tl, tr);
          edges.push(isoBandEdgeBL[cval]);
          edges.push(isoBandEdgeTL[cval]);
        } else if (cval === 144) {
          /* 2100 */
          righttop = interpolateX(minV, br, tr);
          leftbottom = interpolateX(minV, bl, tl);
          lefttop = interpolateX(maxV, bl, tl);
          topright = 1 - interpolateX(maxV, tr, tl);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 26) {
          /* 0122 */
          righttop = 1 - interpolateX(maxV, tr, br);
          leftbottom = 1 - interpolateX(maxV, tl, bl);
          lefttop = 1 - interpolateX(minV, tl, bl);
          topright = interpolateX(minV, tl, tr);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 36) {
          /* 0210 */
          rightbottom = interpolateX(maxV, br, tr);
          bottomright = interpolateX(minV, bl, br);
          topleft = interpolateX(minV, tl, tr);
          topright = interpolateX(maxV, tl, tr);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeBR[cval]);
        } else if (cval === 134) {
          /* 2012 */
          rightbottom = 1 - interpolateX(minV, tr, br);
          bottomright = 1 - interpolateX(maxV, br, bl);
          topleft = 1 - interpolateX(maxV, tr, tl);
          topright = 1 - interpolateX(minV, tr, tl);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeBR[cval]);
        } else if (cval === 9) {
          /* 0021 */
          righttop = 1 - interpolateX(minV, tr, br);
          rightbottom = 1 - interpolateX(maxV, tr, br);
          bottomleft = interpolateX(maxV, bl, br);
          leftbottom = 1 - interpolateX(minV, tl, bl);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 161) {
          /* 2201 */
          righttop = interpolateX(maxV, br, tr);
          rightbottom = interpolateX(minV, br, tr);
          bottomleft = 1 - interpolateX(minV, br, bl);
          leftbottom = interpolateX(maxV, bl, tl);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 37) {
          /* 5th single hexagon cases */
          /* 0211 */
          rightbottom = interpolateX(maxV, br, tr);
          leftbottom = 1 - interpolateX(minV, tl, bl);
          topleft = interpolateX(minV, tl, tr);
          topright = interpolateX(maxV, tl, tr);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeLB[cval]);
        } else if (cval === 133) {
          /* 2011 */
          rightbottom = 1 - interpolateX(minV, tr, br);
          leftbottom = interpolateX(maxV, bl, tl);
          topleft = 1 - interpolateX(maxV, tr, tl);
          topright = 1 - interpolateX(minV, tr, tl);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeLB[cval]);
        } else if (cval === 148) {
          /* 2110 */
          bottomright = interpolateX(minV, bl, br);
          leftbottom = interpolateX(minV, bl, tl);
          lefttop = interpolateX(maxV, bl, tl);
          topright = 1 - interpolateX(maxV, tr, tl);
          edges.push(isoBandEdgeBR[cval]);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 22) {
          /* 0112 */
          bottomright = 1 - interpolateX(maxV, br, bl);
          leftbottom = 1 - interpolateX(maxV, tl, bl);
          lefttop = 1 - interpolateX(minV, tl, bl);
          topright = interpolateX(minV, tl, tr);
          edges.push(isoBandEdgeBR[cval]);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 82) {
          /* 1102 */
          righttop = interpolateX(minV, br, tr);
          bottomright = 1 - interpolateX(minV, br, bl);
          bottomleft = 1 - interpolateX(maxV, br, bl);
          lefttop = 1 - interpolateX(maxV, tl, bl);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 88) {
          /* 1120 */
          righttop = 1 - interpolateX(maxV, tr, br);
          bottomright = interpolateX(maxV, bl, br);
          bottomleft = interpolateX(minV, bl, br);
          lefttop = interpolateX(minV, bl, tl);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 73) {
          /* 1021 */
          righttop = 1 - interpolateX(minV, tr, br);
          rightbottom = 1 - interpolateX(maxV, tr, br);
          bottomleft = interpolateX(maxV, bl, br);
          topleft = 1 - interpolateX(minV, tr, tl);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 97) {
          /* 1201 */
          righttop = interpolateX(maxV, br, tr);
          rightbottom = interpolateX(minV, br, tr);
          bottomleft = 1 - interpolateX(minV, br, bl);
          topleft = interpolateX(maxV, tl, tr);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
        } else if (cval === 145) {
          /* 2101 */
          righttop = interpolateX(minV, br, tr);
          bottomleft = 1 - interpolateX(minV, br, bl);
          leftbottom = interpolateX(maxV, bl, tl);
          topright = 1 - interpolateX(maxV, tr, tl);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeLB[cval]);
        } else if (cval === 25) {
          /* 0121 */
          righttop = 1 - interpolateX(maxV, tr, br);
          bottomleft = interpolateX(maxV, bl, br);
          leftbottom = 1 - interpolateX(minV, tl, bl);
          topright = interpolateX(minV, tl, tr);
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeLB[cval]);
        } else if (cval === 70) {
          /* 1012 */
          rightbottom = 1 - interpolateX(minV, tr, br);
          bottomright = 1 - interpolateX(maxV, br, bl);
          lefttop = 1 - interpolateX(maxV, tl, bl);
          topleft = 1 - interpolateX(minV, tr, tl);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeBR[cval]);
        } else if (cval === 100) {
          /* 1210 */
          rightbottom = interpolateX(maxV, br, tr);
          bottomright = interpolateX(minV, bl, br);
          lefttop = interpolateX(minV, bl, tl);
          topleft = interpolateX(maxV, tl, tr);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeBR[cval]);
        } else if (cval === 34) {
          /* 8-sided cases */
          /* 0202 || 2020 with flipped == 0 */
          if (flipped === 0) {
            righttop = 1 - interpolateX(minV, tr, br);
            rightbottom = 1 - interpolateX(maxV, tr, br);
            bottomright = interpolateX(maxV, bl, br);
            bottomleft = interpolateX(minV, bl, br);
            leftbottom = interpolateX(minV, bl, tl);
            lefttop = interpolateX(maxV, bl, tl);
            topleft = 1 - interpolateX(maxV, tr, tl);
            topright = 1 - interpolateX(minV, tr, tl);
          } else {
            righttop = interpolateX(maxV, br, tr);
            rightbottom = interpolateX(minV, br, tr);
            bottomright = 1 - interpolateX(minV, br, bl);
            bottomleft = 1 - interpolateX(maxV, br, bl);
            leftbottom = 1 - interpolateX(maxV, tl, bl);
            lefttop = 1 - interpolateX(minV, tl, bl);
            topleft = interpolateX(minV, tl, tr);
            topright = interpolateX(maxV, tl, tr);
          }
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeLB[cval]);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 35) {
          /* flipped == 1 state for 0202, and 2020 with flipped == 4*/
          if (flipped === 4) {
            righttop = 1 - interpolateX(minV, tr, br);
            rightbottom = 1 - interpolateX(maxV, tr, br);
            bottomright = interpolateX(maxV, bl, br);
            bottomleft = interpolateX(minV, bl, br);
            leftbottom = interpolateX(minV, bl, tl);
            lefttop = interpolateX(maxV, bl, tl);
            topleft = 1 - interpolateX(maxV, tr, tl);
            topright = 1 - interpolateX(minV, tr, tl);
          } else {
            righttop = interpolateX(maxV, br, tr);
            rightbottom = interpolateX(minV, br, tr);
            bottomright = 1 - interpolateX(minV, br, bl);
            bottomleft = 1 - interpolateX(maxV, br, bl);
            leftbottom = 1 - interpolateX(maxV, tl, bl);
            lefttop = 1 - interpolateX(minV, tl, bl);
            topleft = interpolateX(minV, tl, tr);
            topright = interpolateX(maxV, tl, tr);
          }
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeBL[cval]);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 136) {
          /* 2020 || 0202 with flipped == 0 */
          if (flipped === 0) {
            righttop = interpolateX(maxV, br, tr);
            rightbottom = interpolateX(minV, br, tr);
            bottomright = 1 - interpolateX(minV, br, bl);
            bottomleft = 1 - interpolateX(maxV, br, bl);
            leftbottom = 1 - interpolateX(maxV, tl, bl);
            lefttop = 1 - interpolateX(minV, tl, bl);
            topleft = interpolateX(minV, tl, tr);
            topright = interpolateX(maxV, tl, tr);
          } else {
            righttop = 1 - interpolateX(minV, tr, br);
            rightbottom = 1 - interpolateX(maxV, tr, br);
            bottomright = interpolateX(maxV, bl, br);
            bottomleft = interpolateX(minV, bl, br);
            leftbottom = interpolateX(minV, bl, tl);
            lefttop = interpolateX(maxV, bl, tl);
            topleft = 1 - interpolateX(maxV, tr, tl);
            topright = 1 - interpolateX(minV, tr, tl);
          }
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeLB[cval]);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 153) {
          /* 6-sided polygon cases */
          /* 0101 with flipped == 0 || 2121 with flipped == 2 */
          if (flipped === 0) {
            righttop = interpolateX(minV, br, tr);
            bottomleft = 1 - interpolateX(minV, br, bl);
            leftbottom = 1 - interpolateX(minV, tl, bl);
            topright = interpolateX(minV, tl, tr);
          } else {
            righttop = 1 - interpolateX(maxV, tr, br);
            bottomleft = interpolateX(maxV, bl, br);
            leftbottom = interpolateX(maxV, bl, tl);
            topright = 1 - interpolateX(maxV, tr, tl);
          }
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 102) {
          /* 1010 with flipped == 0 || 1212 with flipped == 2 */
          if (flipped === 0) {
            rightbottom = 1 - interpolateX(minV, tr, br);
            bottomright = interpolateX(minV, bl, br);
            lefttop = interpolateX(minV, bl, tl);
            topleft = 1 - interpolateX(minV, tr, tl);
          } else {
            rightbottom = interpolateX(maxV, br, tr);
            bottomright = 1 - interpolateX(maxV, br, bl);
            lefttop = 1 - interpolateX(maxV, tl, bl);
            topleft = interpolateX(maxV, tl, tr);
          }
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 155) {
          /* 0101 with flipped == 4 || 2121 with flipped == 1 */
          if (flipped === 4) {
            righttop = interpolateX(minV, br, tr);
            bottomleft = 1 - interpolateX(minV, br, bl);
            leftbottom = 1 - interpolateX(minV, tl, bl);
            topright = interpolateX(minV, tl, tr);
          } else {
            righttop = 1 - interpolateX(maxV, tr, br);
            bottomleft = interpolateX(maxV, bl, br);
            leftbottom = interpolateX(maxV, bl, tl);
            topright = 1 - interpolateX(maxV, tr, tl);
          }
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeLB[cval]);
        } else if (cval === 103) {
          /* 1010 with flipped == 4 || 1212 with flipped == 1 */
          if (flipped === 4) {
            rightbottom = 1 - interpolateX(minV, tr, br);
            bottomright = interpolateX(minV, bl, br);
            lefttop = interpolateX(minV, bl, tl);
            topleft = 1 - interpolateX(minV, tr, tl);
          } else {
            rightbottom = interpolateX(maxV, br, tr);
            bottomright = 1 - interpolateX(maxV, br, bl);
            lefttop = 1 - interpolateX(maxV, tl, bl);
            topleft = interpolateX(maxV, tl, tr);
          }
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeBR[cval]);
        } else if (cval === 152) {
          /* 7-sided polygon cases */
          /* 2120 with flipped == 2 || 0102 with flipped == 0 */
          if (flipped === 0) {
            righttop = interpolateX(minV, br, tr);
            bottomright = 1 - interpolateX(minV, br, bl);
            bottomleft = 1 - interpolateX(maxV, br, bl);
            leftbottom = 1 - interpolateX(maxV, tl, bl);
            lefttop = 1 - interpolateX(minV, tl, bl);
            topright = interpolateX(minV, tl, tr);
          } else {
            righttop = 1 - interpolateX(maxV, tr, br);
            bottomright = interpolateX(maxV, bl, br);
            bottomleft = interpolateX(minV, bl, br);
            leftbottom = interpolateX(minV, bl, tl);
            lefttop = interpolateX(maxV, bl, tl);
            topright = 1 - interpolateX(maxV, tr, tl);
          }
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeBR[cval]);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 156) {
          /* 2120 with flipped == 1 || 0102 with flipped == 4 */
          if (flipped === 4) {
            righttop = interpolateX(minV, br, tr);
            bottomright = 1 - interpolateX(minV, br, bl);
            bottomleft = 1 - interpolateX(maxV, br, bl);
            leftbottom = 1 - interpolateX(maxV, tl, bl);
            lefttop = 1 - interpolateX(minV, tl, bl);
            topright = interpolateX(minV, tl, tr);
          } else {
            righttop = 1 - interpolateX(maxV, tr, br);
            bottomright = interpolateX(maxV, bl, br);
            bottomleft = interpolateX(minV, bl, br);
            leftbottom = interpolateX(minV, bl, tl);
            lefttop = interpolateX(maxV, bl, tl);
            topright = 1 - interpolateX(maxV, tr, tl);
          }
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeBL[cval]);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 137) {
          /* 2021 with flipped == 2 || 0201 with flipped == 0 */
          if (flipped === 0) {
            righttop = interpolateX(maxV, br, tr);
            rightbottom = interpolateX(minV, br, tr);
            bottomleft = 1 - interpolateX(minV, br, bl);
            leftbottom = 1 - interpolateX(minV, tl, bl);
            topleft = interpolateX(minV, tl, tr);
            topright = interpolateX(maxV, tl, tr);
          } else {
            righttop = 1 - interpolateX(minV, tr, br);
            rightbottom = 1 - interpolateX(maxV, tr, br);
            bottomleft = interpolateX(maxV, bl, br);
            leftbottom = interpolateX(maxV, bl, tl);
            topleft = 1 - interpolateX(maxV, tr, tl);
            topright = 1 - interpolateX(minV, tr, tl);
          }
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 139) {
          /* 2021 with flipped == 1 || 0201 with flipped == 4 */
          if (flipped === 4) {
            righttop = interpolateX(maxV, br, tr);
            rightbottom = interpolateX(minV, br, tr);
            bottomleft = 1 - interpolateX(minV, br, bl);
            leftbottom = 1 - interpolateX(minV, tl, bl);
            topleft = interpolateX(minV, tl, tr);
            topright = interpolateX(maxV, tl, tr);
          } else {
            righttop = 1 - interpolateX(minV, tr, br);
            rightbottom = 1 - interpolateX(maxV, tr, br);
            bottomleft = interpolateX(maxV, bl, br);
            leftbottom = interpolateX(maxV, bl, tl);
            topleft = 1 - interpolateX(maxV, tr, tl);
            topright = 1 - interpolateX(minV, tr, tl);
          }
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeLB[cval]);
        } else if (cval === 98) {
          /* 1202 with flipped == 2 || 1020 with flipped == 0 */
          if (flipped === 0) {
            righttop = 1 - interpolateX(minV, tr, br);
            rightbottom = 1 - interpolateX(maxV, tr, br);
            bottomright = interpolateX(maxV, bl, br);
            bottomleft = interpolateX(minV, bl, br);
            lefttop = interpolateX(minV, bl, tl);
            topleft = 1 - interpolateX(minV, tr, tl);
          } else {
            righttop = interpolateX(maxV, br, tr);
            rightbottom = interpolateX(minV, br, tr);
            bottomright = 1 - interpolateX(minV, br, bl);
            bottomleft = 1 - interpolateX(maxV, br, bl);
            lefttop = 1 - interpolateX(maxV, tl, bl);
            topleft = interpolateX(maxV, tl, tr);
          }
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 99) {
          /* 1202 with flipped == 1 || 1020 with flipped == 4 */
          if (flipped === 4) {
            righttop = 1 - interpolateX(minV, tr, br);
            rightbottom = 1 - interpolateX(maxV, tr, br);
            bottomright = interpolateX(maxV, bl, br);
            bottomleft = interpolateX(minV, bl, br);
            lefttop = interpolateX(minV, bl, tl);
            topleft = 1 - interpolateX(minV, tr, tl);
          } else {
            righttop = interpolateX(maxV, br, tr);
            rightbottom = interpolateX(minV, br, tr);
            bottomright = 1 - interpolateX(minV, br, bl);
            bottomleft = 1 - interpolateX(maxV, br, bl);
            lefttop = 1 - interpolateX(maxV, tl, bl);
            topleft = interpolateX(maxV, tl, tr);
          }
          edges.push(isoBandEdgeRT[cval]);
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeBL[cval]);
        } else if (cval === 38) {
          /* 0212 with flipped == 2 || 2010 with flipped == 0 */
          if (flipped === 0) {
            rightbottom = 1 - interpolateX(minV, tr, br);
            bottomright = interpolateX(minV, bl, br);
            leftbottom = interpolateX(minV, bl, tl);
            lefttop = interpolateX(maxV, bl, tl);
            topleft = 1 - interpolateX(maxV, tr, tl);
            topright = 1 - interpolateX(minV, tr, tl);
          } else {
            rightbottom = interpolateX(maxV, br, tr);
            bottomright = 1 - interpolateX(maxV, br, bl);
            leftbottom = 1 - interpolateX(maxV, tl, bl);
            lefttop = 1 - interpolateX(minV, tl, bl);
            topleft = interpolateX(minV, tl, tr);
            topright = interpolateX(maxV, tl, tr);
          }
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeLB[cval]);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 39) {
          /* 0212 with flipped == 1 || 2010 with flipped == 4 */
          if (flipped === 4) {
            rightbottom = 1 - interpolateX(minV, tr, br);
            bottomright = interpolateX(minV, bl, br);
            leftbottom = interpolateX(minV, bl, tl);
            lefttop = interpolateX(maxV, bl, tl);
            topleft = 1 - interpolateX(maxV, tr, tl);
            topright = 1 - interpolateX(minV, tr, tl);
          } else {
            rightbottom = interpolateX(maxV, br, tr);
            bottomright = 1 - interpolateX(maxV, br, bl);
            leftbottom = 1 - interpolateX(maxV, tl, bl);
            lefttop = 1 - interpolateX(minV, tl, bl);
            topleft = interpolateX(minV, tl, tr);
            topright = interpolateX(maxV, tl, tr);
          }
          edges.push(isoBandEdgeRB[cval]);
          edges.push(isoBandEdgeBR[cval]);
          edges.push(isoBandEdgeLT[cval]);
        } else if (cval === 85) {
          righttop = 1;
          rightbottom = 0;
          bottomright = 1;
          bottomleft = 0;
          leftbottom = 0;
          lefttop = 1;
          topleft = 0;
          topright = 1;
        }

        if (
          topleft < 0 ||
          topleft > 1 ||
          topright < 0 ||
          topright > 1 ||
          righttop < 0 ||
          righttop > 1 ||
          bottomright < 0 ||
          bottomright > 1 ||
          leftbottom < 0 ||
          leftbottom > 1 ||
          lefttop < 0 ||
          lefttop > 1
        ) {
          console.log(
            "MarchingSquaresJS-isoBands: " +
              cval +
              " " +
              cval_real +
              " " +
              tl +
              "," +
              tr +
              "," +
              br +
              "," +
              bl +
              " " +
              flipped +
              " " +
              topleft +
              " " +
              topright +
              " " +
              righttop +
              " " +
              rightbottom +
              " " +
              bottomright +
              " " +
              bottomleft +
              " " +
              leftbottom +
              " " +
              lefttop
          );
        }

        BandGrid.cells[j][i] = {
          cval: cval,
          cval_real: cval_real,
          flipped: flipped,
          topleft: topleft,
          topright: topright,
          righttop: righttop,
          rightbottom: rightbottom,
          bottomright: bottomright,
          bottomleft: bottomleft,
          leftbottom: leftbottom,
          lefttop: lefttop,
          edges: edges,
        };
      }
    }
  }

  return BandGrid;
}

function BandGrid2AreaPaths(grid) {
  var areas = [];
  var rows = grid.rows;
  var cols = grid.cols;
  var currentPolygon = [];

  for (var j = 0; j < rows; j++) {
    for (var i = 0; i < cols; i++) {
      if (
        typeof grid.cells[j][i] !== "undefined" &&
        grid.cells[j][i].edges.length > 0
      ) {
        /* trace back polygon path starting from this cell */

        var cell = grid.cells[j][i];

        /* get start coordinates */

        var prev = getStartXY(cell),
          next = null,
          p = i,
          q = j;

        if (prev !== null) {
          currentPolygon.push([prev.p[0] + p, prev.p[1] + q]);
          //console.log(cell);
          //console.log("coords: " + (prev.p[0] + p) + " " + (prev.p[1] + q));
        }

        do {
          //console.log(p + "," + q);
          //console.log(grid.cells[q][p]);
          //console.log(grid.cells[q][p].edges);
          //console.log("from : " + prev.x + " " + prev.y + " " + prev.o);

          next = getExitXY(grid.cells[q][p], prev.x, prev.y, prev.o);
          if (next !== null) {
            //console.log("coords: " + (next.p[0] + p) + " " + (next.p[1] + q));
            currentPolygon.push([next.p[0] + p, next.p[1] + q]);
            p += next.x;
            q += next.y;
            prev = next;
          } else {
            //console.log("getExitXY() returned null!");
            break;
          }
          //console.log("to : " + next.x + " " + next.y + " " + next.o);
          /* special case, where we've reached the grid boundaries */
          if (
            q < 0 ||
            q >= rows ||
            p < 0 ||
            p >= cols ||
            typeof grid.cells[q][p] === "undefined"
          ) {
            /* to create a closed path, we need to trace our way
                arround the missing data, until we find an entry
                point again
            */

            /* set back coordinates of current cell */
            p -= next.x;
            q -= next.y;

            //console.log("reached boundary at " + p + " " + q);

            var missing = traceOutOfGridPath(
              grid,
              p,
              q,
              next.x,
              next.y,
              next.o
            );
            if (missing !== null) {
              missing.path.forEach(function (pp) {
                //console.log("coords: " + (pp[0]) + " " + (pp[1]));
                currentPolygon.push(pp);
              });
              p = missing.i;
              q = missing.j;
              prev = missing;
            } else {
              break;
            }
            //console.log(grid.cells[q][p]);
          }
        } while (
          typeof grid.cells[q][p] !== "undefined" &&
          grid.cells[q][p].edges.length > 0
        );

        areas.push(currentPolygon);
        //console.log("next polygon");
        //console.log(currentPolygon);
        currentPolygon = [];
        if (grid.cells[j][i].edges.length > 0) i--;
      }
    }
  }
  return areas;
}

function traceOutOfGridPath(grid, i, j, d_x, d_y, d_o) {
  var cell = grid.cells[j][i];
  var cval = cell.cval_real;
  var p = i + d_x,
    q = j + d_y;
  var path = [];
  var closed = false;

  while (!closed) {
    //console.log("processing cell " + p + "," + q + " " + d_x + " " + d_y + " " + d_o);
    if (
      typeof grid.cells[q] === "undefined" ||
      typeof grid.cells[q][p] === "undefined"
    ) {
      //console.log("which is undefined");
      /* we can't move on, so we have to change direction to proceed further */

      /* go back to previous cell */
      q -= d_y;
      p -= d_x;
      cell = grid.cells[q][p];
      cval = cell.cval_real;

      /* check where we've left defined cells of the grid... */
      if (d_y === -1) {
        /* we came from top */
        if (d_o === 0) {
          /* exit left */
          if (cval & Node3) {
            /* lower left node is within range, so we move left */
            path.push([p, q]);
            d_x = -1;
            d_y = 0;
            d_o = 0;
          } else if (cval & Node2) {
            /* lower right node is within range, so we move right */
            path.push([p + 1, q]);
            d_x = 1;
            d_y = 0;
            d_o = 0;
          } else {
            /* close the path */
            path.push([p + cell.bottomright, q]);
            d_x = 0;
            d_y = 1;
            d_o = 1;
            closed = true;
            break;
          }
        } else if (cval & Node3) {
          path.push([p, q]);
          d_x = -1;
          d_y = 0;
          d_o = 0;
        } else if (cval & Node2) {
          path.push([p + cell.bottomright, q]);
          d_x = 0;
          d_y = 1;
          d_o = 1;
          closed = true;
          break;
        } else {
          path.push([p + cell.bottomleft, q]);
          d_x = 0;
          d_y = 1;
          d_o = 0;
          closed = true;
          break;
        }
      } else if (d_y === 1) {
        /* we came from bottom */
        //console.log("we came from bottom and hit a non-existing cell " + (p + d_x) + "," + (q + d_y) + "!");
        if (d_o === 0) {
          /* exit left */
          if (cval & Node1) {
            /* top right node is within range, so we move right */
            path.push([p + 1, q + 1]);
            d_x = 1;
            d_y = 0;
            d_o = 1;
          } else if (!(cval & Node0)) {
            /* found entry within same cell */
            path.push([p + cell.topright, q + 1]);
            d_x = 0;
            d_y = -1;
            d_o = 1;
            closed = true;
            //console.log("found entry from bottom at " + p + "," + q);
            break;
          } else {
            path.push([p + cell.topleft, q + 1]);
            d_x = 0;
            d_y = -1;
            d_o = 0;
            closed = true;
            break;
          }
        } else if (cval & Node1) {
          path.push([p + 1, q + 1]);
          d_x = 1;
          d_y = 0;
          d_o = 1;
        } else {
          /* move right */
          path.push([p + 1, q + 1]);
          d_x = 1;
          d_y = 0;
          d_o = 1;
          //console.log("wtf");
          //break;
        }
      } else if (d_x === -1) {
        /* we came from right */
        //console.log("we came from right and hit a non-existing cell at " + (p + d_x) + "," + (q + d_y) + "!");
        if (d_o === 0) {
          //console.log("continue at bottom");
          if (cval & Node0) {
            path.push([p, q + 1]);
            d_x = 0;
            d_y = 1;
            d_o = 0;
            //console.log("moving upwards to " + (p + d_x) + "," + (q + d_y) + "!");
          } else if (!(cval & Node3)) {
            /* there has to be an entry into the regular grid again! */
            //console.log("exiting top");
            path.push([p, q + cell.lefttop]);
            d_x = 1;
            d_y = 0;
            d_o = 1;
            closed = true;
            break;
          } else {
            //console.log("exiting bottom");
            path.push([p, q + cell.leftbottom]);
            d_x = 1;
            d_y = 0;
            d_o = 0;
            closed = true;
            break;
          }
        } else {
          //console.log("continue at top");
          if (cval & Node0) {
            path.push([p, q + 1]);
            d_x = 0;
            d_y = 1;
            d_o = 0;
            //console.log("moving upwards to " + (p + d_x) + "," + (q + d_y) + "!");
          } else {
            /* */
            console.log("MarchingSquaresJS-isoBands: wtf");
            break;
          }
        }
      } else if (d_x === 1) {
        /* we came from left */
        //console.log("we came from left and hit a non-existing cell " + (p + d_x) + "," + (q + d_y) + "!");
        if (d_o === 0) {
          /* exit bottom */
          if (cval & Node2) {
            path.push([p + 1, q]);
            d_x = 0;
            d_y = -1;
            d_o = 1;
          } else {
            path.push([p + 1, q + cell.rightbottom]);
            d_x = -1;
            d_y = 0;
            d_o = 0;
            closed = true;
            break;
          }
        } else {
          /* exit top */
          if (cval & Node2) {
            path.push([p + 1, q]);
            d_x = 0;
            d_y = -1;
            d_o = 1;
          } else if (!(cval & Node1)) {
            path.push([p + 1, q + cell.rightbottom]);
            d_x = -1;
            d_y = 0;
            d_o = 0;
            closed = true;
            break;
          } else {
            path.push([p + 1, q + cell.righttop]);
            d_x = -1;
            d_y = 0;
            d_o = 1;
            break;
          }
        }
      } else {
        /* we came from the same cell */
        console.log("MarchingSquaresJS-isoBands: we came from nowhere!");
        break;
      }
    } else {
      /* try to find an entry into the regular grid again! */
      cell = grid.cells[q][p];
      cval = cell.cval_real;
      //console.log("which is defined");

      if (d_x === -1) {
        if (d_o === 0) {
          /* try to go downwards */
          if (
            typeof grid.cells[q - 1] !== "undefined" &&
            typeof grid.cells[q - 1][p] !== "undefined"
          ) {
            d_x = 0;
            d_y = -1;
            d_o = 1;
          } else if (cval & Node3) {
            /* proceed searching in x-direction */
            //console.log("proceeding in x-direction!");
            path.push([p, q]);
          } else {
            /* we must have found an entry into the regular grid */
            path.push([p + cell.bottomright, q]);
            d_x = 0;
            d_y = 1;
            d_o = 1;
            closed = true;
            //console.log("found entry from bottom at " + p + "," + q);
            break;
          }
        } else if (cval & Node0) {
          /* proceed searchin in x-direction */
          console.log("MarchingSquaresJS-isoBands: proceeding in x-direction!");
        } else {
          /* we must have found an entry into the regular grid */
          console.log(
            "MarchingSquaresJS-isoBands: found entry from top at " + p + "," + q
          );
          break;
        }
      } else if (d_x === 1) {
        if (d_o === 0) {
          console.log("MarchingSquaresJS-isoBands: wtf");
          break;
        } else {
          /* try to go upwards */
          if (
            typeof grid.cells[q + 1] !== "undefined" &&
            typeof grid.cells[q + 1][p] !== "undefined"
          ) {
            d_x = 0;
            d_y = 1;
            d_o = 0;
          } else if (cval & Node1) {
            path.push([p + 1, q + 1]);
            d_x = 1;
            d_y = 0;
            d_o = 1;
          } else {
            /* found an entry point into regular grid! */
            path.push([p + cell.topleft, q + 1]);
            d_x = 0;
            d_y = -1;
            d_o = 0;
            closed = true;
            //console.log("found entry from bottom at " + p + "," + q);
            break;
          }
        }
      } else if (d_y === -1) {
        if (d_o === 1) {
          /* try to go right */
          if (typeof grid.cells[q][p + 1] !== "undefined") {
            d_x = 1;
            d_y = 0;
            d_o = 1;
          } else if (cval & Node2) {
            path.push([p + 1, q]);
            d_x = 0;
            d_y = -1;
            d_o = 1;
          } else {
            /* found entry into regular grid! */
            path.push([p + 1, q + cell.righttop]);
            d_x = -1;
            d_y = 0;
            d_o = 1;
            closed = true;
            //console.log("found entry from top at " + p + "," + q);
            break;
          }
        } else {
          console.log("MarchingSquaresJS-isoBands: wtf");
          break;
        }
      } else if (d_y === 1) {
        if (d_o === 0) {
          //console.log("we came from bottom left and proceed to the left");
          /* try to go left */
          if (typeof grid.cells[q][p - 1] !== "undefined") {
            d_x = -1;
            d_y = 0;
            d_o = 0;
          } else if (cval & Node0) {
            path.push([p, q + 1]);
            d_x = 0;
            d_y = 1;
            d_o = 0;
          } else {
            /* found an entry point into regular grid! */
            path.push([p, q + cell.leftbottom]);
            d_x = 1;
            d_y = 0;
            d_o = 0;
            closed = true;
            //console.log("found entry from bottom at " + p + "," + q);
            break;
          }
        } else {
          //console.log("we came from bottom right and proceed to the right");
          console.log("MarchingSquaresJS-isoBands: wtf");
          break;
        }
      } else {
        console.log("MarchingSquaresJS-isoBands: where did we came from???");
        break;
      }
    }

    p += d_x;
    q += d_y;
    //console.log("going on to  " + p + "," + q + " via " + d_x + " " + d_y + " " + d_o);

    if (p === i && q === j) {
      /* bail out, once we've closed a circle path */
      break;
    }
  }

  //console.log("exit with " + p + "," + q + " " + d_x + " " + d_y + " " + d_o);
  return { path: path, i: p, j: q, x: d_x, y: d_y, o: d_o };
}

function deleteEdge(cell, edgeIdx) {
  delete cell.edges[edgeIdx];
  for (var k = edgeIdx + 1; k < cell.edges.length; k++) {
    cell.edges[k - 1] = cell.edges[k];
  }
  cell.edges.pop();
}

function getStartXY(cell) {
  if (cell.edges.length > 0) {
    var e = cell.edges[cell.edges.length - 1];
    //console.log("starting with edge " + e);
    var cval = cell.cval_real;
    switch (e) {
      case 0:
        if (cval & Node1) {
          /* node 1 within range */
          return { p: [1, cell.righttop], x: -1, y: 0, o: 1 };
        } else {
          /* node 1 below or above threshold */
          return { p: [cell.topleft, 1], x: 0, y: -1, o: 0 };
        }
      case 1:
        if (cval & Node2) {
          return { p: [cell.topleft, 1], x: 0, y: -1, o: 0 };
        } else {
          return { p: [1, cell.rightbottom], x: -1, y: 0, o: 0 };
        }
      case 2:
        if (cval & Node2) {
          return { p: [cell.bottomright, 0], x: 0, y: 1, o: 1 };
        } else {
          return { p: [cell.topleft, 1], x: 0, y: -1, o: 0 };
        }
      case 3:
        if (cval & Node3) {
          return { p: [cell.topleft, 1], x: 0, y: -1, o: 0 };
        } else {
          return { p: [cell.bottomleft, 0], x: 0, y: 1, o: 0 };
        }
      case 4:
        if (cval & Node1) {
          return { p: [1, cell.righttop], x: -1, y: 0, o: 1 };
        } else {
          return { p: [cell.topright, 1], x: 0, y: -1, o: 1 };
        }
      case 5:
        if (cval & Node2) {
          return { p: [cell.topright, 1], x: 0, y: -1, o: 1 };
        } else {
          return { p: [1, cell.rightbottom], x: -1, y: 0, o: 0 };
        }
      case 6:
        if (cval & Node2) {
          return { p: [cell.bottomright, 0], x: 0, y: 1, o: 1 };
        } else {
          return { p: [cell.topright, 1], x: 0, y: -1, o: 1 };
        }
      case 7:
        if (cval & Node3) {
          return { p: [cell.topright, 1], x: 0, y: -1, o: 1 };
        } else {
          return { p: [cell.bottomleft, 0], x: 0, y: 1, o: 0 };
        }
      case 8:
        if (cval & Node2) {
          return { p: [cell.bottomright, 0], x: 0, y: 1, o: 1 };
        } else {
          return { p: [1, cell.righttop], x: -1, y: 0, o: 1 };
        }
      case 9:
        if (cval & Node3) {
          return { p: [1, cell.righttop], x: -1, y: 0, o: 1 };
        } else {
          return { p: [cell.bottomleft, 0], x: 0, y: 1, o: 0 };
        }
      case 10:
        if (cval & Node3) {
          return { p: [0, cell.leftbottom], x: 1, y: 0, o: 0 };
        } else {
          return { p: [1, cell.righttop], x: -1, y: 0, o: 1 };
        }
      case 11:
        if (cval & Node0) {
          return { p: [1, cell.righttop], x: -1, y: 0, o: 1 };
        } else {
          return { p: [0, cell.lefttop], x: 1, y: 0, o: 1 };
        }
      case 12:
        if (cval & Node2) {
          return { p: [cell.bottomright, 0], x: 0, y: 1, o: 1 };
        } else {
          return { p: [1, cell.rightbottom], x: -1, y: 0, o: 0 };
        }
      case 13:
        if (cval & Node3) {
          return { p: [1, cell.rightbottom], x: -1, y: 0, o: 0 };
        } else {
          return { p: [cell.bottomleft, 0], x: 0, y: 1, o: 0 };
        }
      case 14:
        if (cval & Node3) {
          return { p: [0, cell.leftbottom], x: 1, y: 0, o: 0 };
        } else {
          return { p: [1, cell.rightbottom], x: -1, y: 0, o: 0 };
        }
      case 15:
        if (cval & Node0) {
          return { p: [1, cell.rightbottom], x: -1, y: 0, o: 0 };
        } else {
          return { p: [0, cell.lefttop], x: 1, y: 0, o: 1 };
        }
      case 16:
        if (cval & Node2) {
          return { p: [cell.bottomright, 0], x: 0, y: 1, o: 1 };
        } else {
          return { p: [0, cell.leftbottom], x: 1, y: 0, o: 0 };
        }
      case 17:
        if (cval & Node0) {
          return { p: [cell.bottomright, 0], x: 0, y: 1, o: 1 };
        } else {
          return { p: [0, cell.lefttop], x: 1, y: 0, o: 1 };
        }
      case 18:
        if (cval & Node3) {
          return { p: [0, cell.leftbottom], x: 1, y: 0, o: 0 };
        } else {
          return { p: [cell.bottomleft, 0], x: 0, y: 1, o: 0 };
        }
      case 19:
        if (cval & Node0) {
          return { p: [cell.bottomleft, 0], x: 0, y: 1, o: 0 };
        } else {
          return { p: [0, cell.lefttop], x: 1, y: 0, o: 1 };
        }
      case 20:
        if (cval & Node0) {
          return { p: [cell.topleft, 1], x: 0, y: -1, o: 0 };
        } else {
          return { p: [0, cell.leftbottom], x: 1, y: 0, o: 0 };
        }
      case 21:
        if (cval & Node1) {
          return { p: [0, cell.leftbottom], x: 1, y: 0, o: 0 };
        } else {
          return { p: [cell.topright, 1], x: 0, y: -1, o: 1 };
        }
      case 22:
        if (cval & Node0) {
          return { p: [cell.topleft, 1], x: 0, y: -1, o: 0 };
        } else {
          return { p: [0, cell.lefttop], x: 1, y: 0, o: 1 };
        }
      case 23:
        if (cval & Node1) {
          return { p: [0, cell.lefttop], x: 1, y: 0, o: 1 };
        } else {
          return { p: [cell.topright, 1], x: 0, y: -1, o: 1 };
        }
      default:
        console.log("MarchingSquaresJS-isoBands: edge index out of range!");
        console.log(cell);
        break;
    }
  }

  return null;
}

function getExitXY(cell, x, y, o) {
  var e,
    id_x,
    d_x,
    d_y,
    cval = cell.cval;
  var d_o;

  switch (x) {
    case -1:
      switch (o) {
        case 0:
          e = isoBandEdgeRB[cval];
          d_x = isoBandNextXRB[cval];
          d_y = isoBandNextYRB[cval];
          d_o = isoBandNextORB[cval];
          break;
        default:
          e = isoBandEdgeRT[cval];
          d_x = isoBandNextXRT[cval];
          d_y = isoBandNextYRT[cval];
          d_o = isoBandNextORT[cval];
          break;
      }
      break;
    case 1:
      switch (o) {
        case 0:
          e = isoBandEdgeLB[cval];
          d_x = isoBandNextXLB[cval];
          d_y = isoBandNextYLB[cval];
          d_o = isoBandNextOLB[cval];
          break;
        default:
          e = isoBandEdgeLT[cval];
          d_x = isoBandNextXLT[cval];
          d_y = isoBandNextYLT[cval];
          d_o = isoBandNextOLT[cval];
          break;
      }
      break;
    default:
      switch (y) {
        case -1:
          switch (o) {
            case 0:
              e = isoBandEdgeTL[cval];
              d_x = isoBandNextXTL[cval];
              d_y = isoBandNextYTL[cval];
              d_o = isoBandNextOTL[cval];
              break;
            default:
              e = isoBandEdgeTR[cval];
              d_x = isoBandNextXTR[cval];
              d_y = isoBandNextYTR[cval];
              d_o = isoBandNextOTR[cval];
              break;
          }
          break;
        case 1:
          switch (o) {
            case 0:
              e = isoBandEdgeBL[cval];
              d_x = isoBandNextXBL[cval];
              d_y = isoBandNextYBL[cval];
              d_o = isoBandNextOBL[cval];
              break;
            default:
              e = isoBandEdgeBR[cval];
              d_x = isoBandNextXBR[cval];
              d_y = isoBandNextYBR[cval];
              d_o = isoBandNextOBR[cval];
              break;
          }
          break;
      }
      break;
  }

  id_x = cell.edges.indexOf(e);
  if (typeof cell.edges[id_x] !== "undefined") {
    deleteEdge(cell, id_x);
  } else {
    //console.log("wrong edges...");
    //console.log(x + " " + y + " " + o);
    //console.log(cell);
    return null;
  }

  cval = cell.cval_real;

  switch (e) {
    case 0:
      if (cval & Node1) {
        /* node 1 within range */
        x = cell.topleft;
        y = 1;
      } else {
        /* node 1 below or above threshold */
        x = 1;
        y = cell.righttop;
      }
      break;
    case 1:
      if (cval & Node2) {
        x = 1;
        y = cell.rightbottom;
      } else {
        x = cell.topleft;
        y = 1;
      }
      break;
    case 2:
      if (cval & Node2) {
        x = cell.topleft;
        y = 1;
      } else {
        x = cell.bottomright;
        y = 0;
      }
      break;
    case 3:
      if (cval & Node3) {
        x = cell.bottomleft;
        y = 0;
      } else {
        x = cell.topleft;
        y = 1;
      }
      break;
    case 4:
      if (cval & Node1) {
        x = cell.topright;
        y = 1;
      } else {
        x = 1;
        y = cell.righttop;
      }
      break;
    case 5:
      if (cval & Node2) {
        x = 1;
        y = cell.rightbottom;
      } else {
        x = cell.topright;
        y = 1;
      }
      break;
    case 6:
      if (cval & Node2) {
        x = cell.topright;
        y = 1;
      } else {
        x = cell.bottomright;
        y = 0;
      }
      break;
    case 7:
      if (cval & Node3) {
        x = cell.bottomleft;
        y = 0;
      } else {
        x = cell.topright;
        y = 1;
      }
      break;
    case 8:
      if (cval & Node2) {
        x = 1;
        y = cell.righttop;
      } else {
        x = cell.bottomright;
        y = 0;
      }
      break;
    case 9:
      if (cval & Node3) {
        x = cell.bottomleft;
        y = 0;
      } else {
        x = 1;
        y = cell.righttop;
      }
      break;
    case 10:
      if (cval & Node3) {
        x = 1;
        y = cell.righttop;
      } else {
        x = 0;
        y = cell.leftbottom;
      }
      break;
    case 11:
      if (cval & Node0) {
        x = 0;
        y = cell.lefttop;
      } else {
        x = 1;
        y = cell.righttop;
      }
      break;
    case 12:
      if (cval & Node2) {
        x = 1;
        y = cell.rightbottom;
      } else {
        x = cell.bottomright;
        y = 0;
      }
      break;
    case 13:
      if (cval & Node3) {
        x = cell.bottomleft;
        y = 0;
      } else {
        x = 1;
        y = cell.rightbottom;
      }
      break;
    case 14:
      if (cval & Node3) {
        x = 1;
        y = cell.rightbottom;
      } else {
        x = 0;
        y = cell.leftbottom;
      }
      break;
    case 15:
      if (cval & Node0) {
        x = 0;
        y = cell.lefttop;
      } else {
        x = 1;
        y = cell.rightbottom;
      }
      break;
    case 16:
      if (cval & Node2) {
        x = 0;
        y = cell.leftbottom;
      } else {
        x = cell.bottomright;
        y = 0;
      }
      break;
    case 17:
      if (cval & Node0) {
        x = 0;
        y = cell.lefttop;
      } else {
        x = cell.bottomright;
        y = 0;
      }
      break;
    case 18:
      if (cval & Node3) {
        x = cell.bottomleft;
        y = 0;
      } else {
        x = 0;
        y = cell.leftbottom;
      }
      break;
    case 19:
      if (cval & Node0) {
        x = 0;
        y = cell.lefttop;
      } else {
        x = cell.bottomleft;
        y = 0;
      }
      break;
    case 20:
      if (cval & Node0) {
        x = 0;
        y = cell.leftbottom;
      } else {
        x = cell.topleft;
        y = 1;
      }
      break;
    case 21:
      if (cval & Node1) {
        x = cell.topright;
        y = 1;
      } else {
        x = 0;
        y = cell.leftbottom;
      }
      break;
    case 22:
      if (cval & Node0) {
        x = 0;
        y = cell.lefttop;
      } else {
        x = cell.topleft;
        y = 1;
      }
      break;
    case 23:
      if (cval & Node1) {
        x = cell.topright;
        y = 1;
      } else {
        x = 0;
        y = cell.lefttop;
      }
      break;
    default:
      console.log("MarchingSquaresJS-isoBands: edge index out of range!");
      console.log(cell);
      return null;
  }

  if (
    typeof x === "undefined" ||
    typeof y === "undefined" ||
    typeof d_x === "undefined" ||
    typeof d_y === "undefined" ||
    typeof d_o === "undefined"
  ) {
    console.log("MarchingSquaresJS-isoBands: undefined value!");
    console.log(cell);
    console.log(x + " " + y + " " + d_x + " " + d_y + " " + d_o);
  }
  return { p: [x, y], x: d_x, y: d_y, o: d_o };
}

function BandGrid2Areas(grid) {
  var areas = [];
  var area_idx = 0;

  grid.cells.forEach(function (g, j) {
    g.forEach(function (gg, i) {
      if (typeof gg !== "undefined") {
        var a = polygon_table[gg.cval](gg);
        if (typeof a === "object" && isArray(a)) {
          if (typeof a[0] === "object" && isArray(a[0])) {
            if (typeof a[0][0] === "object" && isArray(a[0][0])) {
              a.forEach(function (aa) {
                aa.forEach(function (aaa) {
                  aaa[0] += i;
                  aaa[1] += j;
                });
                areas[area_idx++] = aa;
              });
            } else {
              a.forEach(function (aa) {
                aa[0] += i;
                aa[1] += j;
              });
              areas[area_idx++] = a;
            }
          } else {
            console.log(
              "MarchingSquaresJS-isoBands: bandcell polygon with malformed coordinates"
            );
          }
        } else {
          console.log(
            "MarchingSquaresJS-isoBands: bandcell polygon with null coordinates"
          );
        }
      }
    });
  });

  return areas;
}

/**
 * Takes a square or rectangular grid {@link FeatureCollection} of {@link Point} features with z-values and an array of
 * value breaks and generates filled contour isobands.
 *
 * @name isobands
 * @param {FeatureCollection<Point>} pointGrid input points - must be square or rectangular
 * @param {Array<number>} breaks where to draw contours
 * @param {Object} [options={}] options on output
 * @param {string} [options.zProperty='elevation'] the property name in `points` from which z-values will be pulled
 * @param {Object} [options.commonProperties={}] GeoJSON properties passed to ALL isobands
 * @param {Array<Object>} [options.breaksProperties=[]] GeoJSON properties passed, in order, to the correspondent isoband (order defined by breaks)
 * @returns {FeatureCollection<MultiPolygon>} a FeatureCollection of {@link MultiPolygon} features representing isobands
 */
function isobands(pointGrid, breaks, options) {
  // Optional parameters
  options = options || {};
  if (!helpers.isObject(options)) throw new Error("options is invalid");
  var zProperty = options.zProperty || "elevation";
  var commonProperties = options.commonProperties || {};
  var breaksProperties = options.breaksProperties || [];

  // Validation
  invariant.collectionOf(pointGrid, "Point", "Input must contain Points");
  if (!breaks) throw new Error("breaks is required");
  if (!Array.isArray(breaks)) throw new Error("breaks is not an Array");
  if (!helpers.isObject(commonProperties))
    throw new Error("commonProperties is not an Object");
  if (!Array.isArray(breaksProperties))
    throw new Error("breaksProperties is not an Array");

  // Isoband methods
  var matrix = gridToMatrix(pointGrid, { zProperty: zProperty, flip: true });
  var contours = createContourLines(matrix, breaks, zProperty);
  contours = rescaleContours(contours, matrix, pointGrid);

  var multipolygons = contours.map(function (contour, index) {
    if (breaksProperties[index] && !helpers.isObject(breaksProperties[index])) {
      throw new Error("Each mappedProperty is required to be an Object");
    }
    // collect all properties
    var contourProperties = objectAssign__default['default'](
      {},
      commonProperties,
      breaksProperties[index]
    );
    contourProperties[zProperty] = contour[zProperty];
    var multiP = helpers.multiPolygon(contour.groupedRings, contourProperties);
    return multiP;
  });

  return helpers.featureCollection(multipolygons);
}

/**
 * Creates the contours lines (featuresCollection of polygon features) from the 2D data grid
 *
 * Marchingsquares process the grid data as a 3D representation of a function on a 2D plane, therefore it
 * assumes the points (x-y coordinates) are one 'unit' distance. The result of the IsoBands function needs to be
 * rescaled, with turfjs, to the original area and proportions on the map
 *
 * @private
 * @param {Array<Array<number>>} matrix Grid Data
 * @param {Array<number>} breaks Breaks
 * @param {string} [property='elevation'] Property
 * @returns {Array<any>} contours
 */
function createContourLines(matrix, breaks, property) {
  var contours = [];
  for (var i = 1; i < breaks.length; i++) {
    var lowerBand = +breaks[i - 1]; // make sure the breaks value is a number
    var upperBand = +breaks[i];

    var isobandsCoords = isoBands(matrix, lowerBand, upperBand - lowerBand);
    // as per GeoJson rules for creating a Polygon, make sure the first element
    // in the array of LinearRings represents the exterior ring (i.e. biggest area),
    // and any subsequent elements represent interior rings (i.e. smaller area);
    // this avoids rendering issues of the MultiPolygons on the map
    var nestedRings = orderByArea(isobandsCoords);
    var groupedRings = groupNestedRings(nestedRings);
    var obj = {};
    obj["groupedRings"] = groupedRings;
    obj[property] = lowerBand + "-" + upperBand;
    contours.push(obj);
  }
  return contours;
}

/**
 * Transform isobands of 2D grid to polygons for the map
 *
 * @private
 * @param {Array<any>} contours Contours
 * @param {Array<Array<number>>} matrix Grid Data
 * @param {Object} points Points by Latitude
 * @returns {Array<any>} contours
 */
function rescaleContours(contours, matrix, points) {
  // get dimensions (on the map) of the original grid
  var gridBbox = bbox__default['default'](points); // [ minX, minY, maxX, maxY ]
  var originalWidth = gridBbox[2] - gridBbox[0];
  var originalHeigth = gridBbox[3] - gridBbox[1];

  // get origin, which is the first point of the last row on the rectangular data on the map
  var x0 = gridBbox[0];
  var y0 = gridBbox[1];
  // get number of cells per side
  var matrixWidth = matrix[0].length - 1;
  var matrixHeight = matrix.length - 1;
  // calculate the scaling factor between matrix and rectangular grid on the map
  var scaleX = originalWidth / matrixWidth;
  var scaleY = originalHeigth / matrixHeight;

  var resize = function (point) {
    point[0] = point[0] * scaleX + x0;
    point[1] = point[1] * scaleY + y0;
  };

  // resize and shift each point/line of the isobands
  contours.forEach(function (contour) {
    contour.groupedRings.forEach(function (lineRingSet) {
      lineRingSet.forEach(function (lineRing) {
        lineRing.forEach(resize);
      });
    });
  });
  return contours;
}

/*  utility functions */

/**
 * Returns an array of coordinates (of LinearRings) in descending order by area
 *
 * @private
 * @param {Array<LineString>} ringsCoords array of closed LineString
 * @returns {Array} array of the input LineString ordered by area
 */
function orderByArea(ringsCoords) {
  var ringsWithArea = [];
  var areas = [];
  ringsCoords.forEach(function (coords) {
    // var poly = polygon([points]);
    var ringArea = area__default['default'](helpers.polygon([coords]));
    // create an array of areas value
    areas.push(ringArea);
    // associate each lineRing with its area
    ringsWithArea.push({ ring: coords, area: ringArea });
  });
  areas.sort(function (a, b) {
    // bigger --> smaller
    return b - a;
  });
  // create a new array of linearRings coordinates ordered by their area
  var orderedByArea = [];
  areas.forEach(function (area) {
    for (var lr = 0; lr < ringsWithArea.length; lr++) {
      if (ringsWithArea[lr].area === area) {
        orderedByArea.push(ringsWithArea[lr].ring);
        ringsWithArea.splice(lr, 1);
        break;
      }
    }
  });
  return orderedByArea;
}

/**
 * Returns an array of arrays of coordinates, each representing
 * a set of (coordinates of) nested LinearRings,
 * i.e. the first ring contains all the others
 *
 * @private
 * @param {Array} orderedLinearRings array of coordinates (of LinearRings) in descending order by area
 * @returns {Array<Array>} Array of coordinates of nested LinearRings
 */
function groupNestedRings(orderedLinearRings) {
  // create a list of the (coordinates of) LinearRings
  var lrList = orderedLinearRings.map(function (lr) {
    return { lrCoordinates: lr, grouped: false };
  });
  var groupedLinearRingsCoords = [];
  while (!allGrouped(lrList)) {
    for (var i = 0; i < lrList.length; i++) {
      if (!lrList[i].grouped) {
        // create new group starting with the larger not already grouped ring
        var group = [];
        group.push(lrList[i].lrCoordinates);
        lrList[i].grouped = true;
        var outerMostPoly = helpers.polygon([lrList[i].lrCoordinates]);
        // group all the rings contained by the outermost ring
        for (var j = i + 1; j < lrList.length; j++) {
          if (!lrList[j].grouped) {
            var lrPoly = helpers.polygon([lrList[j].lrCoordinates]);
            if (isInside(lrPoly, outerMostPoly)) {
              group.push(lrList[j].lrCoordinates);
              lrList[j].grouped = true;
            }
          }
        }
        // insert the new group
        groupedLinearRingsCoords.push(group);
      }
    }
  }
  return groupedLinearRingsCoords;
}

/**
 * @private
 * @param {Polygon} testPolygon polygon of interest
 * @param {Polygon} targetPolygon polygon you want to compare with
 * @returns {boolean} true if test-Polygon is inside target-Polygon
 */
function isInside(testPolygon, targetPolygon) {
  var points = explode__default['default'](testPolygon);
  for (var i = 0; i < points.features.length; i++) {
    if (!booleanPointInPolygon__default['default'](points.features[i], targetPolygon)) {
      return false;
    }
  }
  return true;
}

/**
 * @private
 * @param {Array<Object>} list list of objects which might contain the 'group' attribute
 * @returns {boolean} true if all the objects in the list are marked as grouped
 */
function allGrouped(list) {
  for (var i = 0; i < list.length; i++) {
    if (list[i].grouped === false) {
      return false;
    }
  }
  return true;
}

module.exports = isobands;
module.exports.default = isobands;