I've had this out here before, but here is a map of 3-point hitch draft on a ripper.   The agronomist at this farm says it matches well with tough spots (more visible on fields that I don't have pictures of).   I would think that you could do a productivity map and have something similar from just ground speed.   There are also interesting pictures from wheel-slip maps, but like draft, you need to be working with a datalogger that will give you access to the required info.