It's a useful thing to have an aerial map of the farms you work, especially when talking with a farmer about his property or adjoining fields.
Simply go to Google Maps and enter your farm's zip code to get the approximate location and zoom in and out from there.
You can save the shot by right-clicking and you can print them out as well.
Enter any address, and you can see it from the air, and zoom in with some detail.
I use a very low-cost iPhone app called "Pinbox" to drop a pin on settes and other features, which helps locate dens quickly and illuminates underground geology. I have also used the app to help me figure my way out of the woods and fields if I get lost (some of the farms I hunt are quite big).
Knowing where water and woods are in relation to field crops, roads, and outbuildings can also give you an idea of where fox and racoon may be bunkered up.
I keep my permissions and aerial maps together, taped up underneath the lid of my veterinary box which is always in the car when I hunt the dogs.