docs: def getAsGdalRaster(self, rasterFieldName, tableName, rasterIdFieldName, rasterId, gdalFormat, newSRID=None, **kwargs):
          """
          Returns a string/buffer representation of the raster in the specified format. Wrapper for
          ST_AsGDALRaster function in the database.
          """
  
          # Check gdalFormat
          if not (gdalFormat in RasterConverter.supportedGdalRasterFormats(self._session)):
              raise ValueError('FORMAT NOT SUPPORTED: {0} format is not supported '
                               'in this PostGIS installation.'.format(gdalFormat))
  
          # Setup srid
          if newSRID:
              srid = ', {0}'.format(newSRID)
          else:
              srid = ''
  
          # Compile options
          if kwargs:
              optionsList = []
              for key, value in kwargs.iteritems():
                  kwargString = "'{0}={1}'".format(key, value)
                  optionsList.append(kwargString)
  
              optionsString = ','.join(optionsList)
              options = ', ARRAY[{0}]'.format(optionsString)
          else:
              options = ''
  
          # Create statement
          statement = '''
                      SELECT ST_AsGDALRaster("{0}", '{1}'{5}{6})
                      FROM "{2}" WHERE "{3}"={4};
                      '''.format(rasterFieldName, gdalFormat, tableName, rasterIdFieldName, rasterId,  options, srid)
  
          # Execute query
          result = self._session.execute(statement).scalar()
  
          return bytes(result).decode('utf-8')