AltosLatLon ul = transform.lat_lon(new AltosPointDouble(x, y));
AltosLatLon center = transform.lat_lon(new AltosPointDouble(x + AltosMap.px_size/2, y + AltosMap.px_size/2));
AltosMapTile tile = map_interface.new_tile(this, ul, center, zoom, maptype,
AltosLatLon ul = transform.lat_lon(new AltosPointDouble(x, y));
AltosLatLon center = transform.lat_lon(new AltosPointDouble(x + AltosMap.px_size/2, y + AltosMap.px_size/2));
AltosMapTile tile = map_interface.new_tile(this, ul, center, zoom, maptype,