108 lines
3.7 KiB
JavaScript
Executable File
108 lines
3.7 KiB
JavaScript
Executable File
import { feature, featureCollection, point, } from "@turf/helpers";
|
|
import { getCoords } from "@turf/invariant";
|
|
import lineSegment from "@turf/line-segment";
|
|
import { featureEach } from "@turf/meta";
|
|
import rbush from "geojson-rbush";
|
|
/**
|
|
* Takes any LineString or Polygon GeoJSON and returns the intersecting point(s).
|
|
*
|
|
* @name lineIntersect
|
|
* @param {GeoJSON} line1 any LineString or Polygon
|
|
* @param {GeoJSON} line2 any LineString or Polygon
|
|
* @returns {FeatureCollection<Point>} point(s) that intersect both
|
|
* @example
|
|
* var line1 = turf.lineString([[126, -11], [129, -21]]);
|
|
* var line2 = turf.lineString([[123, -18], [131, -14]]);
|
|
* var intersects = turf.lineIntersect(line1, line2);
|
|
*
|
|
* //addToMap
|
|
* var addToMap = [line1, line2, intersects]
|
|
*/
|
|
function lineIntersect(line1, line2) {
|
|
var unique = {};
|
|
var results = [];
|
|
// First, normalize geometries to features
|
|
// Then, handle simple 2-vertex segments
|
|
if (line1.type === "LineString") {
|
|
line1 = feature(line1);
|
|
}
|
|
if (line2.type === "LineString") {
|
|
line2 = feature(line2);
|
|
}
|
|
if (line1.type === "Feature" &&
|
|
line2.type === "Feature" &&
|
|
line1.geometry !== null &&
|
|
line2.geometry !== null &&
|
|
line1.geometry.type === "LineString" &&
|
|
line2.geometry.type === "LineString" &&
|
|
line1.geometry.coordinates.length === 2 &&
|
|
line2.geometry.coordinates.length === 2) {
|
|
var intersect = intersects(line1, line2);
|
|
if (intersect) {
|
|
results.push(intersect);
|
|
}
|
|
return featureCollection(results);
|
|
}
|
|
// Handles complex GeoJSON Geometries
|
|
var tree = rbush();
|
|
tree.load(lineSegment(line2));
|
|
featureEach(lineSegment(line1), function (segment) {
|
|
featureEach(tree.search(segment), function (match) {
|
|
var intersect = intersects(segment, match);
|
|
if (intersect) {
|
|
// prevent duplicate points https://github.com/Turfjs/turf/issues/688
|
|
var key = getCoords(intersect).join(",");
|
|
if (!unique[key]) {
|
|
unique[key] = true;
|
|
results.push(intersect);
|
|
}
|
|
}
|
|
});
|
|
});
|
|
return featureCollection(results);
|
|
}
|
|
/**
|
|
* Find a point that intersects LineStrings with two coordinates each
|
|
*
|
|
* @private
|
|
* @param {Feature<LineString>} line1 GeoJSON LineString (Must only contain 2 coordinates)
|
|
* @param {Feature<LineString>} line2 GeoJSON LineString (Must only contain 2 coordinates)
|
|
* @returns {Feature<Point>} intersecting GeoJSON Point
|
|
*/
|
|
function intersects(line1, line2) {
|
|
var coords1 = getCoords(line1);
|
|
var coords2 = getCoords(line2);
|
|
if (coords1.length !== 2) {
|
|
throw new Error("<intersects> line1 must only contain 2 coordinates");
|
|
}
|
|
if (coords2.length !== 2) {
|
|
throw new Error("<intersects> line2 must only contain 2 coordinates");
|
|
}
|
|
var x1 = coords1[0][0];
|
|
var y1 = coords1[0][1];
|
|
var x2 = coords1[1][0];
|
|
var y2 = coords1[1][1];
|
|
var x3 = coords2[0][0];
|
|
var y3 = coords2[0][1];
|
|
var x4 = coords2[1][0];
|
|
var y4 = coords2[1][1];
|
|
var denom = (y4 - y3) * (x2 - x1) - (x4 - x3) * (y2 - y1);
|
|
var numeA = (x4 - x3) * (y1 - y3) - (y4 - y3) * (x1 - x3);
|
|
var numeB = (x2 - x1) * (y1 - y3) - (y2 - y1) * (x1 - x3);
|
|
if (denom === 0) {
|
|
if (numeA === 0 && numeB === 0) {
|
|
return null;
|
|
}
|
|
return null;
|
|
}
|
|
var uA = numeA / denom;
|
|
var uB = numeB / denom;
|
|
if (uA >= 0 && uA <= 1 && uB >= 0 && uB <= 1) {
|
|
var x = x1 + uA * (x2 - x1);
|
|
var y = y1 + uA * (y2 - y1);
|
|
return point([x, y]);
|
|
}
|
|
return null;
|
|
}
|
|
export default lineIntersect;
|