Not really thinking of a protractor, just a coordinate display. Right now, there's not even a way (that I know of) to locate yourself on the surface. Usually the Mars missions have had several coordinate systems, but the most important are:
- Mars Body Fixed Reference: a global latitude/longitude/altitude system
- Surface Fixed Coordinate Frame: NSEW directions relative to the landing site
- Rover Coordinate Frame: XY locations relative to the main axis of the rover.
When I'm looking out of the camera of the small rover, for instance, it would be nice to have feedback that it's pointing at 180 degrees in the RCF, so I know why I have to drive the rover backwards. It would be nice to have SFCF references so that you could drive back to the lander and/or orient communications antennas toward it should that become necessary at some point. And the MBFR coords would be nice to locate your landing site on an external map or for location relative to orbiting satellites, should that become an option.