def _raster_index_to_coords(i, j, bounds = [[-100, -100], [100, 100]],
                            dx = 1, dy = 1):
    """ Converts (i,j) index of raster matrix to real coordinates
    """
    x = (j+0.5)*dx + bounds[0][0]
    y = (i+0.5)*dy + bounds[0][1]
    return x, y