First you take the image of the map and alter it so it is the size you would like it to start on the screen. From here you copy it and then lay the exact same image on the track on top of it. In this way the same altered image of the map is laying on top of itself. You take the second one and you find the exact part of the map that you would like the audience to focus on. This can be something like a town, with the indicative icon and name, or something else. You go into the motion tap and then the Crop options. You begin cropping on all sides of it until you get it down to just a small portion of the map with your focus in it. The best way to do this correctly is to take the top layer map and separate it from the rest of the sequence and alter it so you can see exactly how much you are cutting off. At the bottom of the crop options you have Edge Feather, which you should turn up to about halfway.