Physical Danger
The good news: Unless you're really bad at walking up and down stairs, you're probably not going to break a leg or displace a joint while being a cartographer. Actually, you're probably not in much physical danger at all. Even field work isn't very dangerous; you'll basically just be standing in one place and taking pictures of the landscape.
The worst case scenario is that you step in an ant pile or get your foot caught in a hole. You might get a sprain or break from the latter...but you'll probably avoid those issues by just, you know, looking where you're walking.
There is bad news, though. We hope you're not one of those people who are mortally afraid of paper cuts, because you'll probably be collecting a plethora of them. That, and back issues, since you'll be sitting in front of a computer for long hours at a time. Invest in a good desk chair—or, better yet, one of those giant exercise balls. Then you can bounce while you work.