rasterFunc.py 文件源码

def createRaster(outRas, extCells, pixelSize, cellValues = 'lat', dataType = "float32", noData = -9999, inVector = None):
    NP2GDAL_CONVERSION = { "uint8": 1, "uint16": 2, "int16": 3, 
                          "uint32": 4, "int32": 5, "float32": 6, "float64": 7,
                          "complex64": 10, "complex128": 11,
                         }
    if os.path.exists(outRas):
        print('Raster file already excists!')
        return
    # Create the destination data source        
    xRes = int(numpy.ceil((extCells[2] - extCells[0]) / pixelSize))
    yRes = int(numpy.ceil((extCells[3] - extCells[1]) / pixelSize))

    targetRas = gdal.GetDriverByName('GTiff').Create(outRas, xRes, yRes, 1, NP2GDAL_CONVERSION[dataType])
    targetRas.SetGeoTransform((extCells[0], pixelSize, 0, extCells[3], 0, -pixelSize))
    band = targetRas.GetRasterBand(1)
    band.SetNoDataValue(noData)

    if inVector != None:
        srcVector = ogr.Open(inVector)
        srcLayer = srcVector.GetLayer()
        srs = srcLayer.GetSpatialRef()
        # if the layer is not wgs84
        if srs.GetAttrValue("AUTHORITY", 1) != '4326':
            print('Layer projection should be WGS84!')
            os.remove(outRas)
            return

        # Rasterize clips the raster band
        gdal.RasterizeLayer(targetRas, [1], srcLayer, None, None, [0], ['ALL_TOUCHED=TRUE'])

        g = band.ReadAsArray()

    else:
        g = numpy.zeros((yRes,xRes), eval('numpy.{}'.format(dataType)))

    #populate matrix with random numbers
    for i in range(yRes):
        for j in range(xRes):
            if g[i,j] != noData:
                if cellValues == 'lat':
                    g[i,j] = i
                elif cellValues == 'lon':
                    g[i,j] = j
                elif cellValues == 'random':
                    g[i,j] = numpy.random.randint(50)

    band.WriteArray(g)
    targetRasSRS = osr.SpatialReference()
    targetRasSRS.ImportFromEPSG(4326)
    targetRas.SetProjection(targetRasSRS.ExportToWkt())
    band.FlushCache()

#function to filter raster cells based on the coverage by some vector features