Look up spatial reference system using the projection file.

        Args:
            directory (str):
            filename (str):

        Return:
            int: Spatial Reference ID

def lookupSpatialReferenceID(cls, directory, filename):
        """
        Look up spatial reference system using the projection file.

        Args:
            directory (str):
            filename (str):

        Return:
            int: Spatial Reference ID
        """

        path = os.path.join(directory, filename)

        with open(path, 'r') as f:
            srid = lookupSpatialReferenceID(f.read())

        return srid