"><span><span class="co"># Calculate upstream distance for observed sites (obs) and one</span></span></span>
<span class="r-in"><span><span class="co"># prediction dataset (preds)</span></span></span>
<span class="r-in"><span><span class="va">site.list</span><span class="op">&lt;-</span> <span class="fu">updist_sites</span><span class="op">(</span></span></span>
<span class="r-in"><span>   sites <span class="op">=</span> <span class="fu"><a href="https://rdrr.io/r/base/list.html" class="external-link">list<