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
89 lines (88 loc) • 3.98 kB
JavaScript
import bearing from "@turf/bearing";
import distance from "@turf/distance";
import destination from "@turf/destination";
import lineIntersects from "@turf/line-intersect";
import { flattenEach } from "@turf/meta";
import { point, lineString, } from "@turf/helpers";
import { getCoords } from "@turf/invariant";
/**
* Takes a {@link Point} and a {@link LineString} and calculates the closest Point on the (Multi)LineString.
*
* @name nearestPointOnLine
* @param {Geometry|Feature<LineString|MultiLineString>} lines lines to snap to
* @param {Geometry|Feature<Point>|number[]} pt point to snap from
* @param {Object} [options={}] Optional parameters
* @param {string} [options.units='kilometers'] can be degrees, radians, miles, or kilometers
* @returns {Feature<Point>} closest point on the `line` to `point`. The properties object will contain three values: `index`: closest point was found on nth line part, `dist`: distance between pt and the closest point, `location`: distance along the line between start and the closest point.
* @example
* var line = turf.lineString([
* [-77.031669, 38.878605],
* [-77.029609, 38.881946],
* [-77.020339, 38.884084],
* [-77.025661, 38.885821],
* [-77.021884, 38.889563],
* [-77.019824, 38.892368]
* ]);
* var pt = turf.point([-77.037076, 38.884017]);
*
* var snapped = turf.nearestPointOnLine(line, pt, {units: 'miles'});
*
* //addToMap
* var addToMap = [line, pt, snapped];
* snapped.properties['marker-color'] = '#00f';
*/
function nearestPointOnLine(lines, pt, options) {
if (options === void 0) { options = {}; }
var closestPt = point([Infinity, Infinity], {
dist: Infinity,
});
var length = 0.0;
flattenEach(lines, function (line) {
var coords = getCoords(line);
for (var i = 0; i < coords.length - 1; i++) {
//start
var start = point(coords[i]);
start.properties.dist = distance(pt, start, options);
//stop
var stop_1 = point(coords[i + 1]);
stop_1.properties.dist = distance(pt, stop_1, options);
// sectionLength
var sectionLength = distance(start, stop_1, options);
//perpendicular
var heightDistance = Math.max(start.properties.dist, stop_1.properties.dist);
var direction = bearing(start, stop_1);
var perpendicularPt1 = destination(pt, heightDistance, direction + 90, options);
var perpendicularPt2 = destination(pt, heightDistance, direction - 90, options);
var intersect = lineIntersects(lineString([
perpendicularPt1.geometry.coordinates,
perpendicularPt2.geometry.coordinates,
]), lineString([start.geometry.coordinates, stop_1.geometry.coordinates]));
var intersectPt = null;
if (intersect.features.length > 0) {
intersectPt = intersect.features[0];
intersectPt.properties.dist = distance(pt, intersectPt, options);
intersectPt.properties.location =
length + distance(start, intersectPt, options);
}
if (start.properties.dist < closestPt.properties.dist) {
closestPt = start;
closestPt.properties.index = i;
closestPt.properties.location = length;
}
if (stop_1.properties.dist < closestPt.properties.dist) {
closestPt = stop_1;
closestPt.properties.index = i + 1;
closestPt.properties.location = length + sectionLength;
}
if (intersectPt &&
intersectPt.properties.dist < closestPt.properties.dist) {
closestPt = intersectPt;
closestPt.properties.index = i;
}
// update length
length += sectionLength;
}
});
return closestPt;
}
export default nearestPointOnLine;