Elevation Profile with referenced to AGL.

Since Mission Planner only displays in 2D, I find the Elevation Profile essential in the steep terrain that I survey. I would like an option to display the flight profile with reference to AGL. As it is, I need to try to visually subtract the terrain line from the flight planned line and I have a difficult time determining the nearest I will be to the terrain.
I imagine 2 checkboxes that turn either the GE or SRTM data into the X axis.
Another nice touch would be a report of the lowest and highest AGL altitude in the current flight plan.

Thank you for your consideration

The payload names no files, tests, or entry points; begin by locating Mission Planner’s existing Elevation Profile implementation and its GE/SRTM terrain-data handling. Done means the profile can use terrain as the reference for AGL and reports the lowest and highest AGL altitude for the current flight plan.

Written by the indexing model from the issue text.