Finds the closest item index in tree to geom, vectorized along geom.
geos_nearest(geom, tree)
geos_nearest_indexed(geom, tree)
geos_nearest_hausdorff(geom, tree, densify = NULL)
geos_nearest_frechet(geom, tree, densify = NULL)An integer vector of length geom containing the index
of tree that is closest to each feature in geom.