polygon</a></code>. The color for filling the polygon. The default, 'NA', is to leave polygons unfilled, unless <code>bands.density</code> is specified. If <code>bands.density</code> is specified with a positive value this gives the color of the shading lines.</p></dd>

  <dt>bands.density</dt>
<dd><p>See <code><a href="https://rdrr.io/r/graphics/polygon.html" class="external-link">polygon</a></code>. The density of shading lines for the polygon with the uncertainty bounds, in lines per inch. The default va