mirror of
https://github.com/Turfjs/turf.git
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e5afd5c38b
* Simplify nx config (no point separately caching es and js builds - they both need to be done for any code changes). Fix some no-op type definitions i.e. X extends any, and enforce templated property types as having to extend GeoJsonProperties throughout. * Upgrade typescript. Had to update topojson-* type defs to avoid the P = GeoJsonProperties problem in geojson-rbush. Also fix a couple of floating point precision related issues that eslint now apparently catches! * Retire tslint. * Upgrade eslint and prettier. Add minimal prettier config (defaults have changed) to avoid widespread, minor formatting changes (trailing commas mostly).
73 lines
2.2 KiB
TypeScript
73 lines
2.2 KiB
TypeScript
import {
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Feature,
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GeoJsonProperties,
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MultiPolygon,
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Polygon,
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FeatureCollection,
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} from "geojson";
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import { multiPolygon, polygon } from "@turf/helpers";
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import { geomEach } from "@turf/meta";
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import polygonClipping from "polygon-clipping";
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/**
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* Takes {@link Polygon|polygon} or {@link MultiPolygon|multi-polygon} geometries and
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* finds their polygonal intersection. If they don't intersect, returns null.
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*
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* @name intersect
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* @param {FeatureCollection<Polygon | MultiPolygon>} features the features to intersect
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* @param {Object} [options={}] Optional Parameters
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* @param {Object} [options.properties={}] Translate GeoJSON Properties to Feature
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* @returns {Feature|null} returns a feature representing the area they share (either a {@link Polygon} or
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* {@link MultiPolygon}). If they do not share any area, returns `null`.
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* @example
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* var poly1 = turf.polygon([[
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* [-122.801742, 45.48565],
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* [-122.801742, 45.60491],
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* [-122.584762, 45.60491],
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* [-122.584762, 45.48565],
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* [-122.801742, 45.48565]
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* ]]);
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*
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* var poly2 = turf.polygon([[
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* [-122.520217, 45.535693],
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* [-122.64038, 45.553967],
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* [-122.720031, 45.526554],
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* [-122.669906, 45.507309],
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* [-122.723464, 45.446643],
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* [-122.532577, 45.408574],
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* [-122.487258, 45.477466],
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* [-122.520217, 45.535693]
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* ]]);
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*
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* var intersection = turf.intersect(turf.featureCollection([poly1, poly2]));
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*
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* //addToMap
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* var addToMap = [poly1, poly2, intersection];
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*/
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export default function intersect<
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P extends GeoJsonProperties = GeoJsonProperties,
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>(
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features: FeatureCollection<Polygon | MultiPolygon>,
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options: {
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properties?: P;
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} = {}
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): Feature<Polygon | MultiPolygon, P> | null {
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const geoms: polygonClipping.Geom[] = [];
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geomEach(features, (geom) => {
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geoms.push(geom.coordinates as polygonClipping.Geom);
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});
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if (geoms.length < 2) {
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throw new Error("Must specify at least 2 geometries");
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}
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const intersection = polygonClipping.intersection(
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geoms[0],
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...geoms.slice(1)
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);
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if (intersection.length === 0) return null;
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if (intersection.length === 1)
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return polygon(intersection[0], options.properties);
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return multiPolygon(intersection, options.properties);
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}
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