Hi @http3w,
If you need to get the altitude from longitude and latitude, then your best bet is probably Stick to the ground, as you mentioned. It’s not good for performance but you can add another camera in that area and make it render to a render texture. Having the other camera should keep the tiles from unloading.
Otherwise, I don’t have any other suggestions - but if you find a method that works for you, please post it here!