Google Maps gets called from other apps, usually for GPS functions. So yeah, that's normal. The GPS on the Spica is high battery consumption too and unfortunately some apps tend to leave it on, although 2% usage isn't too bad.
Pantheon at the top by the way is Samsung's home screen app and ugh I've noticed it loves to drain the battery sometimes (plus I think it just generally sucks). If you're on 2.1, I recommend using LauncherPro as your home launcher, it seems to be a lot more efficient and it's fast too.