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- import clone from "@turf/clone";
- import distance from "@turf/distance";
- import { coordAll } from "@turf/meta";
- import { convertLength, } from "@turf/helpers";
- import clustering from "density-clustering";
- /**
- * Takes a set of {@link Point|points} and partition them into clusters according to {@link DBSCAN's|https://en.wikipedia.org/wiki/DBSCAN} data clustering algorithm.
- *
- * @name clustersDbscan
- * @param {FeatureCollection<Point>} points to be clustered
- * @param {number} maxDistance Maximum Distance between any point of the cluster to generate the clusters (kilometers only)
- * @param {Object} [options={}] Optional parameters
- * @param {string} [options.units="kilometers"] in which `maxDistance` is expressed, can be degrees, radians, miles, or kilometers
- * @param {boolean} [options.mutate=false] Allows GeoJSON input to be mutated
- * @param {number} [options.minPoints=3] Minimum number of points to generate a single cluster,
- * points which do not meet this requirement will be classified as an 'edge' or 'noise'.
- * @returns {FeatureCollection<Point>} Clustered Points with an additional two properties associated to each Feature:
- * - {number} cluster - the associated clusterId
- * - {string} dbscan - type of point it has been classified as ('core'|'edge'|'noise')
- * @example
- * // create random points with random z-values in their properties
- * var points = turf.randomPoint(100, {bbox: [0, 30, 20, 50]});
- * var maxDistance = 100;
- * var clustered = turf.clustersDbscan(points, maxDistance);
- *
- * //addToMap
- * var addToMap = [clustered];
- */
- function clustersDbscan(points, maxDistance, options) {
- // Input validation being handled by Typescript
- // collectionOf(points, 'Point', 'points must consist of a FeatureCollection of only Points');
- // if (maxDistance === null || maxDistance === undefined) throw new Error('maxDistance is required');
- // if (!(Math.sign(maxDistance) > 0)) throw new Error('maxDistance is invalid');
- // if (!(minPoints === undefined || minPoints === null || Math.sign(minPoints) > 0)) throw new Error('options.minPoints is invalid');
- if (options === void 0) { options = {}; }
- // Clone points to prevent any mutations
- if (options.mutate !== true)
- points = clone(points);
- // Defaults
- options.minPoints = options.minPoints || 3;
- // create clustered ids
- var dbscan = new clustering.DBSCAN();
- var clusteredIds = dbscan.run(coordAll(points), convertLength(maxDistance, options.units), options.minPoints, distance);
- // Tag points to Clusters ID
- var clusterId = -1;
- clusteredIds.forEach(function (clusterIds) {
- clusterId++;
- // assign cluster ids to input points
- clusterIds.forEach(function (idx) {
- var clusterPoint = points.features[idx];
- if (!clusterPoint.properties)
- clusterPoint.properties = {};
- clusterPoint.properties.cluster = clusterId;
- clusterPoint.properties.dbscan = "core";
- });
- });
- // handle noise points, if any
- // edges points are tagged by DBSCAN as both 'noise' and 'cluster' as they can "reach" less than 'minPoints' number of points
- dbscan.noise.forEach(function (noiseId) {
- var noisePoint = points.features[noiseId];
- if (!noisePoint.properties)
- noisePoint.properties = {};
- if (noisePoint.properties.cluster)
- noisePoint.properties.dbscan = "edge";
- else
- noisePoint.properties.dbscan = "noise";
- });
- return points;
- }
- export default clustersDbscan;
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