eBirds.html'>organizeBirds</a></code>, and a polygon grid-layer, which could be created
by <code><a href='makeGrid.html'>makeGrid</a></code> and splits the visits in the OrganizedBirds
(i.e. data belonging to identified visits) to each grid cell.</p>
<p>If <code>spillOver = NULL</code> the splitting is done spatially according to the
overlay of observations and grid cells, without further consideration of
coherence for visits (visit UID). If <code>spillOver = c("unique", "duplicate")</code>
the splitting wi