\BeginKnitrBlock{rmdnote}<div class="rmdnote">Functions for calculating topological relations use spatial indices to largely speed up spatial query performance.
They achieve that using the Sort-Tile-Recursive (STR) algorithm.
The `st_join` function, mentioned in the next section, also uses the spatial indexing. 
You can learn more at https://www.r-spatial.org/r/2017/06/22/spatial-index.html.</div>\EndKnitrBlock{rmdnote}