@abc.abstractmethod<EOL><INDENT>def coordinate_to_string(self, coordinate):<DEDENT>
return<EOL>
Gets a string representation of a coordinate.

        :param coordinate: a coordinate value
        :type coordinate: ``osid.mapping.Coordinate``
        :return: the display string
        :rtype: ``string``
        :raise: ``InvalidArgument`` -- ``coodrinate.has_record_type(get_coordinate_record_type()`` ) is ``false``
        :raise: ``NullArgument`` -- ``coordinate`` is ``null``
        :raise: ``OperationFailed`` -- unable to complete request
        :raise: ``PermissionDenied`` -- authorization failure

        *compliance: mandatory -- This method must be implemented.*