cts with the equiv method can belong to. Two objects will be equivalent if they belong to the same associative class. </span>

<span class="sd">Directional</span>
<span class="sd">-----------</span>

<span class="sd">Base class for derived Coord and Ax classes, representing &quot;direction&quot; (e.g. &quot;latitude&quot; or &quot;depth&quot;). An abstract equivalence relationship is defined among Directional objects where two objects are equivalent when they have the same &#39;associative&#39; attribute (p