correct/clarify variable names in bound calcs
correct/clarify variable names in bound calcs

perrygeo/python-rasterstats,ozak/python-raster-stats,perrygeo/python-raster-stats,ozak/python-raster-stats,doclements/python-rasterstats,perrygeo/python-rasterstats,doclements/python-rasterstats,perrygeo/python-raster-stats