code: def _get_y_axis(self):
          
          # 0,0 is top/left top top/left pixel. Actual x/y coord of that pixel are (.5,.5).
          y_centers = np.linspace(.5, self.y_size - .5, self.y_size)
          x_centers = y_centers * 0
          return (self.geotransform[3]
                  + self.geotransform[4] * x_centers
                  + self.geotransform[5] * y_centers)
docs: See http://www.gdal.org/gdal_datamodel.html for details.