iv>

    <div class="ref-description section level2">
    <p>Current-meter (<code>cm</code>) instruments determine directions from onboard compasses,
so interpreting velocity components in geographical coordinates requires that
magnetic declination be taken into account.  This is what the present
function does (see “Details”).</p>
    </div>

    <div class="section level2">
    <h2 id="ref-usage">Usage<a class="anchor" aria-label="anchor" href="#ref-usage"></a></h2>
    <div class="sourceCode"><pre cla