Added KML export.

html/index.html

@@ -204,6 +204,7 @@
  </tr>
  </table>
  </div>
+ <button id="export_kml" onclick="exportKML()">Export KML</button>
  <button id="show_trace" type="button" class="greyButton" >History</button>
  <div id="history_collapse" class="collapse">
  <div class="infoRowSpacer">

html/script.js

@@ -4827,3 +4827,168 @@ function updateIconCache() {
  }
  addToIconCache = tryAgain;
 }
+
+
+function zeroPad(num, size) {
+ var s = num + "";
+ while (s.length < size) s = "0" + s;
+ return s;
+}
+
+// Converts "hiccup"-style structures (https://github.com/weavejester/hiccup)
+// to XML.
+function hiccup(node) {
+ if (Array.isArray(node)) {
+ const [tag, attribs, ...children] = node;
+ let attribStrings = [];
+ for (const prop in attribs) {
+ if (!attribs.hasOwnProperty(prop) || attribs[prop] === undefined) {
+ continue;
+ }
+ attribStrings.push(`${prop}="${attribs[prop]}"`);
+ }
+ let xml = `<${tag} ${attribStrings.join(' ')}>`;
+ for (const child of children) {
+ xml += hiccup(child);
+ }
+ xml += `</${tag}>\n`;
+ return xml;
+ } else {
+ return '' + node;
+ }
+}
+
+// Prompts a browser to download a data: URL.
+function download(name, contentType, data) {
+ var link = document.createElement("a");
+ link.download = name;
+ link.href = 'data:' + contentType + ',' + encodeURIComponent(data);
+ document.body.appendChild(link);
+ link.click();
+ document.body.removeChild(link);
+}
+
+function baseExportFilenameForAircrafts(aircrafts) {
+ return aircrafts.map((a) => (a.registration || a.icao).toUpperCase()).join('-');
+}
+
+// Returns an array of {pos, alt, ts} for an aircraft.
+function coordsForExport(plane) {
+ var coords = [];
+ var numSegs = plane.track_linesegs.length;
+ for (let i = 0; i < numSegs; i++) {
+ const proj = plane.track_linesegs[i].fixed.getCoordinates()[1];
+ if (proj) {
+ const pos = ol.proj.toLonLat(proj);
+ const alt = plane.track_linesegs[i].alt_real;
+ const ts = new Date(plane.track_linesegs[i].ts * 1000.0);
+ if (!alt) {
+ throw new Error(`No altitude: ${i} ${pos} ${ts}`);
+ }
+ // Attempt to correct altitude. This could be better?
+ //
+ // 950 feet is the correction factor for an altimeter of 30.15.
+ // 25 feet is the quantum of transponder reporting. 0 altitude
+ // could be reported as -25, so just add 25.
+ coords.push({ pos, alt: (alt + 950 + 25) * 0.3048, ts });
+ } else {
+ console.log(`Skipping ${i}`);
+ }
+ }
+ return coords;
+}
+
+// We use this to give each aircraft a different color track in a
+// multi-select export scenario. From colorbrewer, but I moved the red
+// to be first.
+const EXPORT_RGB_COLORS = [
+ 'e31a1c',
+ 'a6cee3',
+ '1f78b4',
+ 'b2df8a',
+ '33a02c',
+ 'fb9a99',
+ 'fdbf6f',
+ 'ff7f00',
+ 'cab2d6',
+ '6a3d9a',
+ 'ffff99',
+ 'b15928'
+];
+
+// Converts "rrggbb" colors to KML format, "aabbggrr".
+function RGBColorToKMLColor(c) {
+ return 'ff' + c.substring(4, 6) + c.substring(2, 4) + c.substring(0, 2);
+}
+
+// Returns an array of selected planes, ordered by registration-or-ICAO.
+function selectedPlanes() {
+ const planes = [];
+ for (let key in Planes) {
+ if (Planes[key].selected) {
+ planes.push(Planes[key]);
+ }
+ }
+ planes.sort((a, b) => {
+ const keyA = (a.registration || a.icao).toUpperCase();
+ const keyB = (b.registration || b.icao).toUpperCase();
+ if (keyA < keyB) return -1;
+ if (keyA > keyB) return 1;
+ return 0;
+ });
+ return planes;
+}
+
+// Exports currently selected aircraft as KML.
+function exportKML() {
+ const planes = selectedPlanes();
+ const folders = [];
+ for (let i = 0; i < planes.length; i++) {
+ const plane = planes[i];
+ const coords = coordsForExport(plane);
+ const whenObjs = coords.map((c) => {
+ const date = `${c.ts.getUTCFullYear()}-${zeroPad(c.ts.getUTCMonth() + 1, 2)}-${zeroPad(c.ts.getUTCDate(), 2)}`;
+ const time = `T${zeroPad(c.ts.getUTCHours(), 2)}:${zeroPad(c.ts.getUTCMinutes(), 2)}:${zeroPad(c.ts.getUTCSeconds(), 2)}.${zeroPad(c.ts.getUTCMilliseconds(), 3)}Z`;
+ return ["when", {}, date + time];
+ });
+ const coordObjs = coords.map((c) => ["gx:coord", {}, `${c.pos[0]} ${c.pos[1]} ${c.alt}`]);
+ var folder = ["Folder", {},
+ ["name", {}, `${(plane.registration || plane.icao).toUpperCase()} track`],
+ ["Placemark", {},
+ ["name", {}, (plane.registration || plane.icao).toUpperCase()],
+ ["Style", {},
+ ["LineStyle", {},
+ ["color", {}, RGBColorToKMLColor(EXPORT_RGB_COLORS[i % EXPORT_RGB_COLORS.length])],
+ ["width", {}, 6]
+ ],
+ ["IconStyle", {},
+ ["Icon", {},
+ ["href", {}, "http:https://maps.google.com/mapfiles/kml/shapes/airports.png"]
+ ]
+ ]
+ ],
+ ["gx:Track", {},
+ ["altitudeMode", {}, "absolute"],
+ ...whenObjs,
+ ...coordObjs
+ ]
+ ]
+ ];
+ folders.push(folder);
+ }
+ const filename = baseExportFilenameForAircrafts(planes);
+ const prologue = '<?xml version="1.0" encoding="UTF-8"?>\n';
+ const xmlObj = ["kml", {
+ "xmlns": "http:https://www.opengis.net/kml/2.2",
+ "xmlns:gx": "http:https://www.google.com/kml/ext/2.2"
+ },
+ ["Folder", {},
+ ...folders
+ ]
+ ];
+ const xml = prologue + hiccup(xmlObj);
+ download(
+ filename + '-track.kml',
+ 'application/vnd.google-earth.kml+xml',
+ xml);
+}