>calc_catchment</span><span class='op'>(</span>
  <span class='va'>polygonlayer</span>,
  <span class='va'>targetlayer</span>,
  <span class='va'>calccols</span>,
  distance <span class='op'>=</span> <span class='fl'>500</span>,
  projection <span class='op'>=</span> <span class='fu'><a href='https://rdrr.io/r/base/paste.html'>paste0</a></span><span class='op'>(</span><span class='st'>"+proj=aea +lat_1=90 +lat_2=-18.416667 "</span>,
    <span class='st'>"+lat_0=0 +lon_0=10 +x_0=0 +y_0=0 +ellps=GRS80"</span>