I know that the drawings shown are to illustrate how to color zones in SketchUp, not claimed to be realistic WiFi coverage maps. But in case anyone didn't realize: you will need to measure both signal and noise (or "quality") at a bunch of locations to create your map, which will have more complicated shapes than the circular zones depicted. Walls, cabinets, furniture, etc. block WiFi signals in complex ways, and noise sources such as cordless phones provide varying interference. Generating the "heat map" in the first place is harder than painting it in SketchUp!