I am planning a Flyby of a castle in Ireland for later this year using Litchi mission. I have discovered that the castle itself is 90 feet high BUT it sits on an elevated mound and I will have to start the mission from much lower ground about 200m away. I cannot visit the site in advance because I live in Canada. Any advice on how to determine the safe altitude to set for this Google Earth gives no information ( that I can see ) about ground elevation and I have no access to printed maps of the area. The only thing I can think of is to fly the bird when I get there, note the safe altitude and then modify my mission accordingly, but I would prefer to save my battery power if possible. Thanks for any suggestions.