Apple Maps Color legend - where is it

Where can one find the legend for map colors for Apple Maps? It seems this information only exists within the minds of Apple. I have spend too much time searching for it and something every map should have should be readily available so it must not exist. Please prove me wrong.

I'm not talking about road colors. I'm talking about colors assigned to areas on the map, such as water, which is obviously blue. Green is apparently used for parks or areas of vegetation, but there are different shades of green used and these green areas may or may not be a park or recreation area.

I can only assume that this "maps 101" information is kept secret for competitive reasons, because I cannnot fathom why there is not a link to all the color codes, icons and legends used throughout this otherwise excellent tool.