I am using the google maps javascript api to make polygons based on user input (I'm not using the Drawing library, just the straight-up v3). I want to be able to export these features to kml. However, there is nothing I can see in the javascript api that allows me to do this.
I know that maps engine lite has an "export to kml" feature.
Is there some google library I am missing that allows for exporting to kml? I've seen some solutions where the polygon's attributes are sent to a textarea and that is used to generate kml, but I'd much prefer using an existing library rather than making my own kml file.
I am using the google maps javascript api to make polygons based on user input (I'm not using the Drawing library, just the straight-up v3). I want to be able to export these features to kml. However, there is nothing I can see in the javascript api that allows me to do this.
I know that maps engine lite has an "export to kml" feature.
Is there some google library I am missing that allows for exporting to kml? I've seen some solutions where the polygon's attributes are sent to a textarea and that is used to generate kml, but I'd much prefer using an existing library rather than making my own kml file.
Share Improve this question asked Nov 5, 2013 at 16:41 SkittermSkitterm 4,5959 gold badges42 silver badges56 bronze badges1 Answer
Reset to default 6The Blitz GMap Editor allows you to export KML (uses the drawing manager to create and edit them, but you could use your code).
Example
To KML code from Blitz GMap Editor. Depends on xmlwriter.js
this.toKML = function() {
var result = mapToObject();
var xw = new XMLWriter('UTF-8');
xw.formatting = 'indented'; //add indentation and newlines
xw.indentChar = ' '; //indent with spaces
xw.indentation = 2; //add 2 spaces per level
xw.writeStartDocument();
xw.writeStartElement('kml');
xw.writeAttributeString("xmlns", "http://www.opengis/kml/2.2");
xw.writeStartElement('Document');
for (var i = 0; i < result.overlays.length; i++) {
xw.writeStartElement('Placemark');
xw.writeStartElement('name');
xw.writeCDATA(result.overlays[i].title);
xw.writeEndElement();
xw.writeStartElement('description');
xw.writeCDATA(result.overlays[i].content);
xw.writeEndElement();
if (result.overlays[i].type == "marker") {
xw.writeStartElement('Point');
xw.writeElementString('extrude', '1');
xw.writeElementString('altitudeMode', 'relativeToGround');
xw.writeElementString('coordinates', result.overlays[i].position.lng.toString() + "," + result.overlays[i].position.lat.toString() + ",0");
xw.writeEndElement();
} else if (result.overlays[i].type == "polygon" || result.overlays[i].type == "rectangle" || result.overlays[i].type == "circle") {
xw.writeStartElement('Polygon');
xw.writeElementString('extrude', '1');
xw.writeElementString('altitudeMode', 'relativeToGround');
if (result.overlays[i].type == "rectangle") {
//its a polygon
xw.writeStartElement('outerBoundaryIs');
xw.writeStartElement('LinearRing');
xw.writeStartElement("coordinates");
xw.writeString(result.overlays[i].bounds.sw.lng + "," + result.overlays[i].bounds.sw.lat + ",0");
xw.writeString(result.overlays[i].bounds.ne.lng + "," + result.overlays[i].bounds.sw.lat + ",0");
xw.writeString(result.overlays[i].bounds.ne.lng + "," + result.overlays[i].bounds.ne.lat + ",0");
xw.writeString(result.overlays[i].bounds.sw.lng + "," + result.overlays[i].bounds.ne.lat + ",0");
xw.writeEndElement();
xw.writeEndElement();
xw.writeEndElement();
}
if (result.overlays[i].type == "circle") {
//its a polygon, approximate a circle by a circular 64 sided polygon.
xw.writeStartElement('outerBoundaryIs');
xw.writeStartElement('LinearRing');
xw.writeStartElement("coordinates");
var d2r = Math.PI / 180; // degrees to radians
var r2d = 180 / Math.PI; // radians to degrees
var earthsradius = 6378137; // 6378137 is the radius of the earth in meters
var dir = 1; // clockwise
var points = 64;
// find the raidus in lat/lon
var rlat = (result.overlays[i].radius / earthsradius) * r2d;
var rlng = rlat / Math.cos(result.overlays[i].center.lat * d2r);
var extp = new Array();
if (dir == 1) {
var start = 0;
var end = points + 1
} // one extra here makes sure we connect the line
else {
var start = points + 1;
var end = 0
}
for (var j = start;
(dir == 1 ? j < end : j > end); j = j + dir) {
var theta = Math.PI * (j / (points / 2));
ey = result.overlays[i].center.lng + (rlng * Math.cos(theta)); // center a + radius x * cos(theta)
ex = result.overlays[i].center.lat + (rlat * Math.sin(theta)); // center b + radius y * sin(theta)
xw.writeString(ey + "," + ex + ",0");
}
xw.writeEndElement();
xw.writeEndElement();
xw.writeEndElement();
} else {
for (var j = 0; j < result.overlays[i].paths.length; j++) {
if (j == 0) {
xw.writeStartElement('outerBoundaryIs');
} else {
xw.writeStartElement('innerBoundaryIs');
}
xw.writeStartElement('LinearRing');
xw.writeStartElement("coordinates");
for (var k = 0; k < result.overlays[i].paths[j].length; k++) {
xw.writeString(result.overlays[i].paths[j][k].lng + "," + result.overlays[i].paths[j][k].lat + ",0");
}
xw.writeEndElement();
xw.writeEndElement();
xw.writeEndElement();
}
}
xw.writeEndElement();
} else if (result.overlays[i].type == "polyline") {
xw.writeStartElement('LineString');
xw.writeElementString('extrude', '1');
xw.writeElementString('altitudeMode', 'relativeToGround');
xw.writeStartElement("coordinates");
for (var j = 0; j < result.overlays[i].path.length; j++) {
xw.writeString(result.overlays[i].path[j].lng + "," + result.overlays[i].path[j].lat + ",0");
}
xw.writeEndElement();
xw.writeEndElement();
}
xw.writeEndElement(); // END PlaceMarker
}
xw.writeEndElement();
xw.writeEndElement();
xw.writeEndDocument();
var xml = xw.flush(); //generate the xml string
xw.close(); //clean the writer
xw = undefined; //don't let visitors use it, it's closed
//set the xml
document.getElementById('kmlString').value = xml;
}