Jeremy Logan Jeremy Logan - 2 years ago 152
Android Question

How to compute a radius around a point in an Android MapView?

I have a MapView that I'm displaying a "useful radius" (think accuracy of coordinate) in. Using

's Projection's metersToEquatorPixels, which is admittedly just for equatorial distance) isn't giving me an accurate enough distance (in pixels). How would you compute this if you wanted to display a circle around your coordinate, given radius?

Answer Source

So, Google Maps uses a Mercator projection. This means that the further you get from the equator the more distorted the distances become. According to this discussion, the proper way to convert for distances is something like:

public static int metersToRadius(float meters, MapView map, double latitude) {
    return (int) (map.getProjection().metersToEquatorPixels(meters) * (1/ Math.cos(Math.toRadians(latitude))));         
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