I need to define a data structure which for convenience reasons for users using my software should be related to WGS84 - if possible. So that it makes it easy for users to use my software, convert from e.g. GPS data they get from Android or iOS system calls, and convert these forth and back to "my" coordinates.
However, my mapping application uses various UTM projections, depending which part of the world is shown. Thus I want to abstract away the need for a user to deal with various projections.
Ideally I just provide WGS84 as single projection - but I need height(!) since this is a 3D application and objects are on different floors with different elevation.
I've read some article here detailing about elevation here: https://geozoneblog.wordpress.com/2015/03/27/wgs84-versus-nad83-vertical/
What is the best way to provide WGS84 with elevation info, or shouldn't I do this?