georaster.py 文件源码

def from_array(cls, raster, geo_transform, proj4, 
        gdal_dtype=gdal.GDT_Float32, nodata=None):
        """ Create a georaster object from numpy array and georeferencing information.

        :param raster: 2-D NumPy array of raster to load
        :type raster: np.array
        :param geo_transform: a Geographic Transform tuple of the form \
        (top left x, w-e cell size, 0, top left y, 0, n-s cell size (-ve))
        :type geo_transform: tuple
        :param proj4: a proj4 string representing the raster projection
        :type proj4: str
        :param gdal_dtype: a GDAL data type (default gdal.GDT_Float32)
        :type gdal_dtype: int
        :param nodata: None or the nodata value for this array
        :type nodata: None, int, float, str

        :returns: GeoRaster object
        :rtype: GeoRaster

         """

        if len(raster.shape) > 2:
            nbands = raster.shape[2]
        else:
            nbands = 1

        # Create a GDAL memory raster to hold the input array
        mem_drv = gdal.GetDriverByName('MEM')
        source_ds = mem_drv.Create('', raster.shape[1], raster.shape[0],
                         nbands, gdal_dtype)

        # Set geo-referencing
        source_ds.SetGeoTransform(geo_transform)
        srs = osr.SpatialReference()
        srs.ImportFromProj4(proj4)
        source_ds.SetProjection(srs.ExportToWkt())

        # Write input array to the GDAL memory raster
        for b in range(0,nbands):
            if nbands > 1:
                r = raster[:,:,b]
            else:
                r = raster
            source_ds.GetRasterBand(b+1).WriteArray(r)
            if nodata != None:
                source_ds.GetRasterBand(b+1).SetNoDataValue(nodata)

        # Return a georaster instance instantiated by the GDAL raster
        return cls(source_ds)