I still have to conclude the Andes example as given is misleading. It strongly implies ray-tracing "fixes" the problems shown. A footnote alone can't fix that (

I still have to conclude the Andes example as given is misleading. It strongly implies ray-tracing "fixes" the problems shown. A footnote alone can't fix that (or is the wrong way to fix it). This clause under the picture is particularly problematic: "but it's disconnected from the underlying physics of what makes real shadows occur: rays of light not hitting a surface due to another surface in the way." -- As I mentioned, you often DON'T want that effect for the type of map shown, and that alone is not the main cause of the differences in the illustration. I'd bet money I can tweak the brightness-mapping curve to make the left look very similar to the right. (As somebody else mentioned, the actual curve depends on weather and local textures etc. such that both techniques are ultimately rough approximations.)