def raster_to_gtiff(tif, geotif, change_nodata=False, change_gdal_type=False):
        """Converting Raster format to GeoTIFF.

        Args:
            tif: source raster file path.
            geotif: output raster file path.
            change_nodata: change NoDataValue to -9999 or not.
            gdal_type (:obj:`pygeoc.raster.GDALDataType`): GDT_Float32 as default.
            change_gdal_type: If True, output the Float32 data type.
        """
        rst_file = RasterUtilClass.read_raster(tif)
        nodata = rst_file.noDataValue
        if change_nodata:
            if not MathClass.floatequal(rst_file.noDataValue, DEFAULT_NODATA):
                nodata = DEFAULT_NODATA
                rst_file.data[rst_file.data == rst_file.noDataValue] = DEFAULT_NODATA
        gdal_type = rst_file.dataType
        if change_gdal_type:
            gdal_type = GDT_Float32
        RasterUtilClass.write_gtiff_file(geotif, rst_file.nRows, rst_file.nCols, rst_file.data,
                                         rst_file.geotrans, rst_file.srs, nodata,
                                         gdal_type)