lumns already exist in <code>sites</code>
or sites.gpkg already exists in <code>lsn_path</code>. Default = TRUE.</p>
<p>#' @details <code>updist_sites()</code> calculates the total hydrologic distance from
each observed or prediction point feature to
the stream outlet (i.e. the most downstream location in the
stream network), when movement is restricted to the stream
network. We refer to this as the upstream distance.</p>
<p>Upstream distances are measured in the map projection units for the
<code>sf</code>