def pbf(self, bbox, geo_col=None, scale=4096):
        col = geo_col or self._transform()
        w, s, e, n = bbox.extent
        trans = self._trans_scale(col, -w, -s,
                                  scale / (e - w),
                                  scale / (n - s))
        return self.extra(select={'pbf': 'ST_AsText(%s)' % trans})
Returns tranlated and scaled geometries suitable for Mapbox vector
dataset/ETHPy150Open bkg/django-spillway/spillway/query.py/GeoQuerySet.pbf