GeoPandas plotting - add warning note about making choropleths with "extensive" variables #51
Description
At the end of notebook 2, we make a plot of the population density, and then also show as comparison a misleading choropleth of the population count.
We could expand this into a note warning about plotting with variables that are directly associated with the area (this is called "extensive variables" in https://r-spatial.org/book/05-Attributes.html#sec-extensiveintensive, and from the plotting section "using filled polygons for extensive variables may not be a good idea because the map colours conflate amount and area size"), and that for a choropleth we always need a variable relative to the area (or one that is constant, such as land use category)