You should visit the site below, where you’ll find an extraordinary series of graphics that allow you to watch the battle unfold. You’ll get a god’s-eye view of decisive moments in the battle, and also be able to see the terrain and troop positions from the perspective of generals on both sides.

The author concludes that General Lee’s limited view of the Union forces, as well as faulty intelligence, greatly contributed to the Confederate defeat (for which we should still be thankful 150 years later): “Time would show that Gettysburg had been the high tide of the Confederacy, its most audacious battle and its greatest loss.”

http://www.smithsonianmag.com/history-archaeology/A-Cutting-Edge-Second-Look-at-the-Battle-of-Gettysburg.html