import * as turf from 'turf' export class GeoOperations { static surfaceAreaInSqMeters(feature: any) { return turf.area(feature); } static centerpoint(feature: any) { const newFeature= turf.center(feature); newFeature.properties = feature.properties; newFeature.id = feature.id; return newFeature; } static featureIsContainedInAny(feature: any, shouldNotContain: any[], maxOverlapPercentage: number): boolean { // Returns 'false' if no problematic intersection is found if (feature.geometry.type === "Point") { const coor = feature.geometry.coordinates; for (const shouldNotContainElement of shouldNotContain) { let shouldNotContainBBox = BBox.get(shouldNotContainElement); let featureBBox = BBox.get(feature); if (!featureBBox.overlapsWith(shouldNotContainBBox)) { continue; } if (this.inside(coor, shouldNotContainElement)) { return true } } return false; } if (feature.geometry.type === "Polygon" || feature.geometry.type === "MultiPolygon") { const poly = feature; let featureBBox = BBox.get(feature); const featureSurface = GeoOperations.surfaceAreaInSqMeters(poly); for (const shouldNotContainElement of shouldNotContain) { const shouldNotContainBBox = BBox.get(shouldNotContainElement); const overlaps = featureBBox.overlapsWith(shouldNotContainBBox) if (!overlaps) { continue; } // Calculate the surface area of the intersection // If it is too big, refuse try { const intersection = turf.intersect(poly, shouldNotContainElement); if (intersection == null) { continue; } const intersectionSize = turf.area(intersection); const ratio = intersectionSize / featureSurface; if (ratio * 100 >= maxOverlapPercentage) { console.log("Refused", poly.id, " due to ", shouldNotContainElement.id, "intersection ratio is ", ratio, "which is bigger then the target ratio of ", (maxOverlapPercentage / 100)) return true; } } catch (exception) { console.log("EXCEPTION CAUGHT WHILE INTERSECTING: ", exception); // We assume that this failed due to an intersection return true; } } return false; // No problematic intersections found } return false; } public static inside(pointCoordinate, feature): boolean { // ray-casting algorithm based on // http://www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html if (feature.geometry.type === "Point") { return false; } const x: number = pointCoordinate[0]; const y: number = pointCoordinate[1]; let poly = feature.geometry.coordinates[0]; var inside = false; for (let i = 0, j = poly.length - 1; i < poly.length; j = i++) { const coori = poly[i]; const coorj = poly[j]; const xi = coori[0]; const yi = coori[1]; const xj = coorj[0]; const yj = coorj[1]; const intersect = ((yi > y) != (yj > y)) && (x < (xj - xi) * (y - yi) / (yj - yi) + xi); if (intersect) { inside = !inside; } } return inside; }; } class BBox{ readonly maxLat: number; readonly maxLon: number; readonly minLat: number; readonly minLon: number; constructor(coordinates) { this.maxLat = Number.MIN_VALUE; this.maxLon = Number.MIN_VALUE; this.minLat = Number.MAX_VALUE; this.minLon = Number.MAX_VALUE; for (const coordinate of coordinates) { this.maxLon = Math.max(this.maxLon, coordinate[0]); this.maxLat = Math.max(this.maxLat, coordinate[1]); this.minLon = Math.min(this.minLon, coordinate[0]); this.minLat = Math.min(this.minLat, coordinate[1]); } this.check(); } private check() { if (isNaN(this.maxLon) || isNaN(this.maxLat) || isNaN(this.minLon) || isNaN(this.minLat)) { console.log(this); throw "BBOX has NAN"; } } public overlapsWith(other: BBox) { this.check(); other.check(); if (this.maxLon < other.minLon) { return false; } if (this.maxLat < other.minLat) { return false; } if (this.minLon > other.maxLon) { return false; } return this.minLat <= other.maxLat; } static get(feature) { if (feature.bbox?.overlapsWith === undefined) { if (feature.geometry.type === "MultiPolygon") { let coordinates = []; for (const coorlist of feature.geometry.coordinates) { coordinates = coordinates.concat(coorlist[0]); } feature.bbox = new BBox(coordinates); } else if (feature.geometry.type === "Polygon") { feature.bbox = new BBox(feature.geometry.coordinates[0]); } else if (feature.geometry.type === "LineString") { feature.bbox = new BBox(feature.geometry.coordinates); } else if (feature.geometry.type === "Point") { // Point feature.bbox = new BBox([feature.geometry.coordinates]); } else { throw "Cannot calculate bbox, unknown type " + feature.geometry.type; } } return feature.bbox; } }