geo.map_pixel(point_x, point_y)

        Return value of raster in location
        Note: (point_x, point_y) must belong to the geographic coordinate system and
        the coverage of the raster

def map_pixel(self, point_x, point_y):
        '''
        geo.map_pixel(point_x, point_y)

        Return value of raster in location
        Note: (point_x, point_y) must belong to the geographic coordinate system and
        the coverage of the raster
        '''
        row, col = map_pixel(point_x, point_y,
                             self.x_cell_size, self.y_cell_size, self.xmin, self.ymax)
        try:
            return self.raster[row, col]
        except:
            raise RasterGeoError('Make sure the point belongs to the raster coverage \
                                 and it is in the correct geographic coordinate system.')