See here for an example in UgCS:

Graph the mission plan, with elevation on the Y axis. One line shows the estimated path of the drone (requires knowing climb/descent angle of the UAV and how it will get between each waypoint). The bottom graph shows the terrain.
Next, add bands for the minimum and maximum allowable AGL, and any MSL restrictions from fences.
Finally, highlight any conflicting areas and show what is wrong along the route. Consider highlighting mission segments in violation of constraints in red.
Consider how to extend the validators to custom restrictions such a LOS plugins or similar.