utils.py 文件源码

def decompress(points, schema):
    """
    Decode patch encoded with lazperf.
    'points' is a pcpatch in wkb
    """

    # retrieve number of points in wkb pgpointcloud patch
    npoints = patch_numpoints(points)
    hexbuffer = unhexlify(points[34:])
    hexbuffer += hexa_signed_int32(npoints)

    # uncompress
    s = json.dumps(schema).replace("\\", "")
    dtype = buildNumpyDescription(json.loads(s))
    lazdata = bytes(hexbuffer)

    arr = np.fromstring(lazdata, dtype=np.uint8)
    d = Decompressor(arr, s)
    output = np.zeros(npoints * dtype.itemsize, dtype=np.uint8)
    decompressed = d.decompress(output)

    return decompressed