def map_pixel(self, point_x, point_y):
row, col = map_pixel(point_x, point_y,<EOL>self.x_cell_size, self.y_cell_size, self.xmin, self.ymax)<EOL>try:<EOL><INDENT>return self.raster[row, col]<EOL><DEDENT>except:<EOL><INDENT>raise RasterGeoError('<STR_LIT>')<EOL><DEDENT>
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