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3bbd7590c4
* Replaced polygon-clipping with polyclip-ts --------- Co-authored-by: colin <cmurphy@terabase.energy> Co-authored-by: James Beard <james@smallsaucepan.com>
71 lines
2.2 KiB
TypeScript
71 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 * as polyclip from "polyclip-ts";
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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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* @function
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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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function intersect<P extends GeoJsonProperties = GeoJsonProperties>(
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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: polyclip.Geom[] = [];
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geomEach(features, (geom) => {
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geoms.push(geom.coordinates as polyclip.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 = polyclip.intersection(geoms[0], ...geoms.slice(1));
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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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export { intersect };
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export default intersect;
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