Just wondering how you guys avoid exceeding the maximum legal altitude in your area? I'm in Australia so I have to stay under 400ft to avoid other aircraft from 500ft upwards. I have set the max height warning on my iOSD mini to 120 meters which is about 400ft so I can see when I am coming close to the max height but I've recently realised this height is in relation to my takeoff position where as other aircrafts altitude are all related to sea level. Meaning that obviously if I take off from a location that is 100ft or more above sea level I am actually entering restricted airspace. Am I correct in thinking this? I've had a search around the forum but can't find anything on the subject.