I surveyed a room and the students had a lot of trouble in one area of the room. If you look at the survey it is all blue. but if you look VERY close you will see a slight band of lighter color towards the bad signal range. However I would have NEVER saw this unless the students complained. I think the color visualization should be more drastic to show the bad or weaker spots more clearly.
In NetSpot 2.0 you will be able to choose your own colors for wireless signal visualization. However, it’s a kind of industry standard to use cold colors for bad reception areas and hot colors to visualize good signal.