Relative Altitude

Can someone tell me how to set up mission planner to report relative altitude as apposed to absolute altitude? I’d like ground zero to read “0” instead of my height above sea level.

In some places in MissionPlaner you already have height relative to home. Take a look at the HUD altitude for instance.

And to the “Quick” view items you can add or change to altoffsethome

If you’re worried about the altitude displayed on a OSD (like minimosd) you can set parameter DEVOPTIONS,2

On the OSD it displays normally, starting at “0”. However, in the Mavlink telemetry download it displays absolute altitude at the Home Waypoint and in the downlink to my transmitter. In other words, my height above sea level.