utils.py 文件源码

def binary_mask(rast, mask, nodata=-9999, invert=False):
    '''
    Applies an arbitrary, binary mask (data in [0,1]) where pixels with
    a value of 1 are pixels to be masked out. Arguments:
        rast    A gdal.Dataset or a NumPy array
        mask    A gdal.Dataset or a NumPy array
        nodata  The NoData value; defaults to -9999.
        invert  Invert the mask? (tranpose meaning of 0 and 1); defaults to False.
    '''
    # Can accept either a gdal.Dataset or numpy.array instance
    if not isinstance(rast, np.ndarray):
        rastr = rast.ReadAsArray()

    else:
        rastr = rast.copy()

    if not isinstance(mask, np.ndarray):
        maskr = mask.ReadAsArray()

    else:
        maskr = mask.copy()

    if not np.alltrue(np.equal(rastr.shape[-2:], maskr.shape[-2:])):
        raise ValueError('Raster and mask do not have the same shape')

    # Convert Boolean arrays to ones and zeros
    if maskr.dtype == bool:
        maskr = maskr.astype(np.int0)

    # Transform into a "1-band" array and apply the mask
    if maskr.shape != rastr.shape:
        maskr = maskr.reshape((1, maskr.shape[-2], maskr.shape[-1]))\
            .repeat(rastr.shape[0], axis=0) # Copy the mask across the "bands"

    # TODO Compare to place(), e.g.,
    # np.place(rastr, mask.repeat(rastr.shape[0], axis=0), (nodata,))
    # Mask out areas that match the mask (==1)
    if invert:
        rastr[maskr < 1] = nodata

    else:
        rastr[maskr > 0] = nodata

    return rastr