def clear(self):
        self._mSurface = pg.Surface((int(self.width), int(self.height)),flags = pg.SRCALPHA)
        return None
Converts a longitude, latitude coordinate pair for the given zoom level.
dataset/ETHPy150Open sightmachine/SimpleCV/SimpleCV/DrawingLayer.py/DrawingLayer.clear--crossover with--dataset/ETHPy150Open AppScale/appscale/AppServer/lib/django-1.4/django/contrib/gis/maps/google/zoom.py/GoogleZoom.lonlat_to_pixel