That map is great, I have seen it many times, and Hanover is a good home for it. (Since apparently it is not cool enough for Gettysburg anymore.)
Hanover was the site of a significant cavalry battle on June 30, 1863 (they day before the battle of Gettysburg). Union General Kilpatrick ran J.E.B. Stuart out of town and kept him occupied, which kept Stuart away from Gettysburg, which handicapped Lee and helped give the Union a victory at Gettysburg.
The new visitor's center in Gettysburg is all flashy, loud multimedia stuff now. I liked the old light-up map better. Though the restoration of the Cyclorama is very, very good.