I am working on a new simulation project that requires large scale, real-world terrain and imagery (GIS). By large scale, I mean that I would like to support databases that cover something on the order of 10,000 square miles that include at least height data and satellite imagery. Using data of this size also means that the engine must be capable of managing the coordinate systems/projections such that some reasonable precision can be maintained.
To my knowledge OpenSceneGraph is the only graphics engine out there that makes this easy (via paged terrain support, osgEarth, etc.) However, it would be nice to be able to leverage many of the other great features AAA-quality game engines bring to the table. (OSG is just a graphics engine, really. I've been using it for over a decade, but I don't want to be fixed only to what I know.)
I've seen many tutorials online for importing small postage-stamp sized bits of terrain into Unreal. I haven't seen anything on this scale.
Asked here: "Very large terrains in Unreal-4" there is a link to Unreal's "World Composition" feature. This seems to shift coordinates around and also doesn't seem geared towards using real-world data.
How can I represent real-world terrain data on these scales in a mainstream game engine?