\BeginKnitrBlock{rmdnote}<div class="rmdnote">Of course, the limitations of 2D Earth projections apply as much to vector as to raster data.
At best we can comply with two out of three spatial properties (distance, area, direction).
Therefore, the task at hand determines which projection to choose. 
For instance, if we are interested in a density (points per grid cell or inhabitants per grid cell) we should use an equal-area projection (see also Chapter \@ref(location)).</div>\EndKnitrBlock{rmdnote}