i figured that too. its like an 1.5 hour drive me to really measure it, so im kinda taking the chances on here.Looks a lot like 3x6 subway. Do you only have a picture to work from?
I believe SketchUp can do that.I saw on C.S.I. once where the took the known heights in the environment in a picture to triangulate an unknown size of an object...
maybe theres an app for that...