code: def distance(self, lat, lon):
  		'''distance of this tile from a given lat/lon'''
  		(tlat, tlon) = self.coord((TILES_WIDTH/2,TILES_HEIGHT/2))
  		return mp_util.gps_distance(lat, lon, tlat, tlonf distance(self, lat, lon):
  		'''distance of this tile from a given lat/lon'''
  		(tlat, tlon) = self.coord((TILES_WIDTH/2,TILES_HEIGHT/2))
  		return mp_util.gps_distance(lat, lon, tlat, tlon)
docs: distance of this tile from a given lat/lon