Route.js

class Route {
    constructor(startnode, originalroute) {
        if (originalroute == null) { // create a new route with just a node
            this.waypoints = [];
            this.minlat = Infinity;
            this.maxlat = 0;
            this.minlon = Infinity;
            this.maxlon = 0;
            this.waypoints.push(startnode);
            this.distance = 0;
            this.doublingsup = 0;
        } else { // make a deep copy of a route
            this.waypoints = [];
            for (let i = 0; i < originalroute.waypoints.length; i++) {
                this.waypoints.push(originalroute.waypoints[i]);
            }
            this.minlat = originalroute.minlat;
            this.maxlat = originalroute.maxlat;
            this.minlon = originalroute.minlon;
            this.maxlon = originalroute.maxlon;
            this.distance = originalroute.distance;
            this.doublingsup = originalroute.doublingsup;
        }
    }

    addWaypoint(node, dist, doublingsup) {
        this.waypoints.push(node);
        this.distance += dist;
        this.minlat = min(this.minlat, node.lat);
        this.maxlat = max(this.maxlat, node.lat);
        this.minlon = min(this.minlon, node.lon);
        this.maxlon = max(this.maxlon, node.lon);
        this.doublingsup += doublingsup;
    }

    area() { // rough approximation of the area
        return (this.maxlat - this.minlat) * (this.maxlon - this.minlon);
    }

    show() {
        stroke(255, 255, 255, 55);
        strokeWeight(5);
        for (let i = 0; i < this.waypoints.length - 1; i++) {
            let from = createVector(this.waypoints[i].x, this.waypoints[i].y);
            let to = createVector(this.waypoints[i + 1].x, this.waypoints[i + 1].y);
            let vline = p5.Vector.sub(to, from);
            let hue = map(i, 0, this.waypoints.length - 1, 0, 155);
            stroke(hue, 255, 255, 0.5);
            line(from.x, from.y, to.x, to.y);
            if (showSteps) {
                fill(hue, 255, 55, 0.8);
                noStroke();
                textSize(8);
                let textangle = vline.heading() + HALF_PI;
                text(i, 10 * cos(textangle) + (from.x + to.x) / 2 - 5, 10 * sin(textangle) + (from.y + to.y) / 2);
            }

        }
        noStroke();
        if (this.waypoints.length > 0) {
            fill(0, 255, 255, 0.8);
            ellipse(this.waypoints[0].x, this.waypoints[0].y, 20, 20); //show the first waypoint
        }
        fill(149, 255, 255, 0.8);
        ellipse(this.waypoints[bestroute.waypoints.length - 1].x, this.waypoints[bestroute.waypoints.length - 1].y, 20, 20); //show the last waypoint
    }

    exportGPX() {
        let xmlDoc = document.implementation.createDocument(null, "gpx");
        let x = xmlDoc.getElementsByTagName('gpx');
        x[0].setAttribute("xmlns:gpxtpx", "http://www.garmin.com/xmlschemas/TrackPointExtension/v1");
        x[0].setAttribute("version", "1.1");
        x[0].setAttribute("xm1ns", "http://www.topografix.com/GPX/1/1"); // for some weird reason the XML DOM won't add an attribute called exactly 'xmlns', so I'm fudging it and replacing it later.
        let trk = xmlDoc.createElement("trk");
        let trknumber = xmlDoc.createElement("type");
        trknumber.appendChild(xmlDoc.createTextNode("9"));
        trk.appendChild(trknumber);
        let trkseg = xmlDoc.createElement("trkseg");

        let now = new Date();

        for (let i = 0; i < this.waypoints.length; i++) {
            let trkpt = xmlDoc.createElement("trkpt");
            trkpt.setAttribute("lat", this.waypoints[i].lat);
            trkpt.setAttribute("lon", this.waypoints[i].lon);
            let ele = xmlDoc.createElement("ele");
            ele.appendChild(xmlDoc.createTextNode("2000"));
            trkpt.appendChild(ele);
            let timenode = xmlDoc.createElement("time");
            let fakedDate = new Date(now.getFullYear(), now.getMonth(), now.getDate()-1, now.getHours(), now.getMinutes() + i); // create a fake timestamp for the route by adding 1 min for each waypoint
            timenode.appendChild(xmlDoc.createTextNode(fakedDate.toISOString()));
            trkpt.appendChild(timenode);
            trkseg.appendChild(trkpt);
        }

        trk.appendChild(trkseg);
        xmlDoc.documentElement.appendChild(trk);

        var serializer = new XMLSerializer();
        let XMLString = serializer.serializeToString(xmlDoc)
        let XMLwriter = createWriter('route.gpx');
        XMLString = XMLString.replace('xm1ns','xmlns'); // for some weird reason the XML DOM won't add an attribute called exactly 'xmlns', so I'm fudging it.
        XMLwriter.write(XMLString);
        XMLwriter.close();
    }
}