See this video (4K), mentioned here. It is a zig-zag mission, in sunlight (july in Spain), over dry grass. Waypoints alternate 60/80cm high.
Terrain on the far waypoints from the camera is slightly elevated (may be around 1m).
Rangefinders are TFmini and I2CXL-MaxSonar-EZ4.
Note ROI waypoint forgotten after hitting grass.