quiv</span>
<span class="sd">      eq_index</span>
<span class="sd">      eq_in</span>

<span class="sd">    Examples:</span>
<span class="sd">    &gt;&gt;&gt; depth.is_equiv(longitude) # generally different directions.</span>
<span class="sd">    False</span>
<span class="sd">    &gt;&gt;&gt; depth.make_equiv(longitude) # don&#39;t do this in real work</span>
<span class="sd">    &gt;&gt;&gt; depth.is_equiv(longitude) # uphysically:</span>
<span class="sd">    True </span>
<span class="sd">    &quot;&quot;