12345678910111213141516171819202122232425262728293031323334353637383940414243444546474849505152535455565758596061626364656667686970717273747576 |
- import { coordEach } from "@turf/meta";
- /**
- * Takes a GeoJSON Feature or FeatureCollection and truncates the precision of the geometry.
- *
- * @name truncate
- * @param {GeoJSON} geojson any GeoJSON Feature, FeatureCollection, Geometry or GeometryCollection.
- * @param {Object} [options={}] Optional parameters
- * @param {number} [options.precision=6] coordinate decimal precision
- * @param {number} [options.coordinates=3] maximum number of coordinates (primarly used to remove z coordinates)
- * @param {boolean} [options.mutate=false] allows GeoJSON input to be mutated (significant performance increase if true)
- * @returns {GeoJSON} layer with truncated geometry
- * @example
- * var point = turf.point([
- * 70.46923055566859,
- * 58.11088890802906,
- * 1508
- * ]);
- * var options = {precision: 3, coordinates: 2};
- * var truncated = turf.truncate(point, options);
- * //=truncated.geometry.coordinates => [70.469, 58.111]
- *
- * //addToMap
- * var addToMap = [truncated];
- */
- function truncate(geojson, options) {
- if (options === void 0) { options = {}; }
- // Optional parameters
- var precision = options.precision;
- var coordinates = options.coordinates;
- var mutate = options.mutate;
- // default params
- precision =
- precision === undefined || precision === null || isNaN(precision)
- ? 6
- : precision;
- coordinates =
- coordinates === undefined || coordinates === null || isNaN(coordinates)
- ? 3
- : coordinates;
- // validation
- if (!geojson)
- throw new Error("<geojson> is required");
- if (typeof precision !== "number")
- throw new Error("<precision> must be a number");
- if (typeof coordinates !== "number")
- throw new Error("<coordinates> must be a number");
- // prevent input mutation
- if (mutate === false || mutate === undefined)
- geojson = JSON.parse(JSON.stringify(geojson));
- var factor = Math.pow(10, precision);
- // Truncate Coordinates
- coordEach(geojson, function (coords) {
- truncateCoords(coords, factor, coordinates);
- });
- return geojson;
- }
- /**
- * Truncate Coordinates - Mutates coordinates in place
- *
- * @private
- * @param {Array<any>} coords Geometry Coordinates
- * @param {number} factor rounding factor for coordinate decimal precision
- * @param {number} coordinates maximum number of coordinates (primarly used to remove z coordinates)
- * @returns {Array<any>} mutated coordinates
- */
- function truncateCoords(coords, factor, coordinates) {
- // Remove extra coordinates (usually elevation coordinates and more)
- if (coords.length > coordinates)
- coords.splice(coordinates, coords.length);
- // Truncate coordinate decimals
- for (var i = 0; i < coords.length; i++) {
- coords[i] = Math.round(coords[i] * factor) / factor;
- }
- return coords;
- }
- export default truncate;
|