Trying to find a specific transition name.

Hi everyone,
I'm working on a video right now and I want to do a transition i've seen before. Usually I would google search for tutorials but I don't actually know the name of the transition. A good example is in the halo wars trailer at 28-30 second mark. You can see it here:







If anyone knows the name of the transition (or the best way to accomplish it) please let me know.

Thank you in advance,
Elie Z