geo.to_tiff(filename)

        Saves GeoRaster as geotiff filename.tif with type datatype

        If GeoRaster does not have datatype, then it tries to assign a type.
        You can assign the type yourself by setting
         geo.datatype = 'gdal.GDT_'+type

def to_tiff(self, filename):
        '''
        geo.to_tiff(filename)

        Saves GeoRaster as geotiff filename.tif with type datatype

        If GeoRaster does not have datatype, then it tries to assign a type.
        You can assign the type yourself by setting
         geo.datatype = 'gdal.GDT_'+type
        '''
        if self.datatype is None:
            self.datatype = gdal_array.NumericTypeCodeToGDALTypeCode(self.raster.data.dtype)
            if self.datatype is None:
                if self.raster.data.dtype.name.find('int') !=- 1:
                    self.raster = self.raster.astype(np.int32)
                    self.datatype = gdal_array.NumericTypeCodeToGDALTypeCode(self.raster.data.dtype)
                else:
                    self.raster = self.raster.astype(np.float64)
                    self.datatype = gdal_array.NumericTypeCodeToGDALTypeCode(self.raster.data.dtype)
        self.raster.data[self.raster.mask] = self.nodata_value
        create_geotiff(filename, self.raster, gdal.GetDriverByName('GTiff'), self.nodata_value,
                       self.shape[1], self.shape[0], self.geot, self.projection, self.datatype)