def getWkt(self):
        """
        Returns GSSHA projection WKT string
        """
        gssha_pro_card = self.getCard("#PROJECTION_FILE")
        if gssha_pro_card is None:
            raise ValueError("#PROJECTION_FILE card not found ...")

        with tmp_chdir(self.project_directory):
            gssha_prj_file = gssha_pro_card.value.strip('"').strip("'")
            with open(gssha_prj_file) as pro_file:
                wkt_string = pro_file.read()
            return wkt_string