Question

I have made my own map using the google maps api. It is a custom map type based on a really big image.

Is there anyway I can reset the latlng coordinates so they are relative to my image and not the earth’s default latlng coordinates?

I.E. Make the top left corner of the image (0,0).

Thanks.

Answer 1

Yes, it’s possible with your own custom projection definitions. I modified this lunar surface example with a simple projection that takes the top-left corner to be (0,0) and bottom-right, (50,50). You will most likely need to change the values to work with your app.

I played around a bit with the limits and there looks to still be a hard limit of +/- 90 for latitudes and +/- 180 for longitudes. The longitude will wrap around at 180 degrees. That is, it appears to be impossible to define a custom coordinate of, say, (100, 200).

See the modified lunar surface demo here, click anywhere to display the custom latLng in an alert:

http://jsfiddle.net/yV6xv/79/

function percentProjection() {};

percentProjection.prototype.fromLatLngToPoint = function(latlng) {
    // pixel size of tile at zoom 0
    var max = 256;

    // define bottom-right corner as (50, 50)
    var x = max * latlng.lng() / 50;
    var y = max * latlng.lat() / 50;
    return new google.maps.Point(x, y);
};

percentProjection.prototype.fromPointToLatLng = function(pixel) {
    // inverse conversion
    var max = 256;
    var lng = pixel.x / max * 50;
    var lat = pixel.y / max * 50;
    return new google.maps.LatLng(lat, lng);
};