ut. We determine whether the cursor is hovering over a stratum and if so, display the appropriate tooltip.</p>
<div class="figure">
<img src="hover_stratum.jpg" alt=""><p class="caption">screenshot of tooltip on stratum</p>
</div>
<p>If the mouse cursor is not hovering over a stratum, we determine whether it is hovering over an alluvium polygon and if so, display different information in the tooltip.</p>
<div class="figure">
<img src="hover_alluvium.jpg" alt=""><p class="caption">screenshot of tooltip on al