Imagine, if you will, your average mapping canvas - most of the time its probably an A1 sized piece of paper. Sometimes though average doesn't cut it, sometimes you need a dynamic canvas the size of a building - sometimes you need yourself projection mapping. Unlike the rickety old projectors your parents used to show their lame holiday slides on, modern projectors can display slick computer animations (and of course maps) at such larger-than-life scales that when seen live is simply astounding. I know if I was a town planner I'd want people to see my ideas this way. Heck, if i was a town planner I'd want to see any ideas this way.