/a></span>(<span class='no'>od_agg</span>, <span class='no'>aggzones_sf</span>)</div><div class='output co'>#&gt; <span class='warning'>Warning: st_centroid assumes attributes are constant over geometries of x</span></div><div class='output co'>#&gt; <span class='warning'>Warning: st_centroid does not give correct centroids for longitude/latitude data</span></div><div class='input'><span class='fu'>plot</span>(<span class='no'>flowlines</span>, <span class='kw'>lwd</span> <span class='kw'>=</span> <span cla