getMetersPerPixelAtLatitude method
Implementation
@override
Future<double> getMetersPerPixelAtLatitude(double latitude) async {
//https://wiki.openstreetmap.org/wiki/Zoom_levels
var circumference = 40075017.686;
var zoom = _map.getZoom();
return circumference * cos(latitude * (pi / 180)) / pow(2, zoom + 9);
}