node-red-contrib-tak-registration
Version:
A Node-RED node to register to TAK and to help wrap files as datapackages to send to TAK
108 lines • 3.46 kB
JavaScript
// index.ts
import { getCoords, getType } from "@turf/invariant";
import { point, featureCollection } from "@turf/helpers";
import { bbox as calcBbox } from "@turf/bbox";
import { explode } from "@turf/explode";
import { nearestPoint } from "@turf/nearest-point";
function polygonTangents(pt, polygon) {
const pointCoords = getCoords(pt);
const polyCoords = getCoords(polygon);
let rtan = [];
let ltan = [];
let eprev;
const bbox = calcBbox(polygon);
let nearestPtIndex = 0;
let nearest = null;
if (pointCoords[0] > bbox[0] && pointCoords[0] < bbox[2] && pointCoords[1] > bbox[1] && pointCoords[1] < bbox[3]) {
nearest = nearestPoint(pt, explode(polygon));
nearestPtIndex = nearest.properties.featureIndex;
}
const type = getType(polygon);
switch (type) {
case "Polygon":
rtan = polyCoords[0][nearestPtIndex];
ltan = polyCoords[0][0];
if (nearest !== null) {
if (nearest.geometry.coordinates[1] < pointCoords[1])
ltan = polyCoords[0][nearestPtIndex];
}
eprev = isLeft(
polyCoords[0][0],
polyCoords[0][polyCoords[0].length - 1],
pointCoords
);
[rtan, ltan] = processPolygon(
polyCoords[0],
pointCoords,
eprev,
rtan,
ltan
);
break;
case "MultiPolygon":
var closestFeature = 0;
var closestVertex = 0;
var verticesCounted = 0;
for (var i = 0; i < polyCoords[0].length; i++) {
closestFeature = i;
var verticeFound = false;
for (var i2 = 0; i2 < polyCoords[0][i].length; i2++) {
closestVertex = i2;
if (verticesCounted === nearestPtIndex) {
verticeFound = true;
break;
}
verticesCounted++;
}
if (verticeFound) break;
}
rtan = polyCoords[0][closestFeature][closestVertex];
ltan = polyCoords[0][closestFeature][closestVertex];
eprev = isLeft(
polyCoords[0][0][0],
polyCoords[0][0][polyCoords[0][0].length - 1],
pointCoords
);
polyCoords.forEach(function(ring) {
[rtan, ltan] = processPolygon(ring[0], pointCoords, eprev, rtan, ltan);
});
break;
}
return featureCollection([point(rtan), point(ltan)]);
}
function processPolygon(polygonCoords, ptCoords, eprev, rtan, ltan) {
for (let i = 0; i < polygonCoords.length; i++) {
const currentCoords = polygonCoords[i];
let nextCoordPair = polygonCoords[i + 1];
if (i === polygonCoords.length - 1) {
nextCoordPair = polygonCoords[0];
}
const enext = isLeft(currentCoords, nextCoordPair, ptCoords);
if (eprev <= 0 && enext > 0) {
if (!isBelow(ptCoords, currentCoords, rtan)) {
rtan = currentCoords;
}
} else if (eprev > 0 && enext <= 0) {
if (!isAbove(ptCoords, currentCoords, ltan)) {
ltan = currentCoords;
}
}
eprev = enext;
}
return [rtan, ltan];
}
function isAbove(point1, point2, point3) {
return isLeft(point1, point2, point3) > 0;
}
function isBelow(point1, point2, point3) {
return isLeft(point1, point2, point3) < 0;
}
function isLeft(point1, point2, point3) {
return (point2[0] - point1[0]) * (point3[1] - point1[1]) - (point3[0] - point1[0]) * (point2[1] - point1[1]);
}
var turf_polygon_tangents_default = polygonTangents;
export {
turf_polygon_tangents_default as default,
polygonTangents
};
//# sourceMappingURL=index.js.map