an class="special">&gt;</span></code>
          </p>
<h6>
<a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.h4"></a>
            <span class="phrase"><a name="geometry.reference.algorithms.is_valid.is_valid_2_with_message.conformance"></a></span><a class="link" href="is_valid_2_with_message.html#geometry.reference.algorithms.is_valid.is_valid_2_with_message.conformance">Conformance</a>
          </h6>
<p>
            The function is_valid is not defined by OGC.
          </p>
<h6>
<a n