Global Mapper v25.0

Adjusting high res DEM to match regional DEM?

tim53 Global Mapper UserTrusted User
I have Mars rover orthomosaics and DEMs that I want to merge with orbiter-derived orthomosaics and DEMs.  Is there a way to define a terrain grid with the same boundary as the [irregular] rover-based DEM so that I can subtract the difference between the rover and orbiter based dems and "lower" the rover based DEMs so that it is at the exact elevation of the orbiter DEM at the edges?