Naturally. it’s much more accurate when calculating distances at the same parallel.
IF the calculation is happening in unreal? I can screenshot the correction code for you. it’s a basic mathematical equation that adjusts from Linear to ellipsoid approximation.
If you are calculating on the file or in GIS, the distance usually already has an option for it to adjust, which is why error margins are so minimal. - however you should note that this distance is not equal to the Pixel distance of the flat file - unless the projection is correctly adjusted.
The whole issue is just that. A map/heightfiled is flat - and usually not in a 1:1 scale (but that’s another issue entirely since Scale can be calculated separately if need be).
This - within Unreal and with mind to a Gaming world where you do require collision - becomes very problematic because within unreal maps are also essentially “FLAT”. What we often re-create is not the reality of the solar system but a flat earth similar to what flat earthers model as gospel (the difference being we all know it is just an easier representation than having a spherical earth which rotates in relation to a sun/light source). Can it work? Yes. Is it accurate? Hell no, it’s an approximation.
Further more, unless correctly adjust it, far away tiles do not automatically “bend” as they should.
What does this mean? This means that on their own, the far tiles and objects in a game will be linearly visible no matter what at a distance. If you have a tower of 1km, at a distance of 10km you will see a tower of 1km in height instead of having over half (or whatever the actual math is) be not visible because of earth’s curvature.
If you were to create an ellipsoid of 6,371KM approx radius and selectively sculpt areas based on a correctly projected heightfield you would still get marginal errors in calculations, but were it possible memory load wise - the result would be FAR more accurate compared to a flat representation when calculating line of sight distances.
For me anyway, the issue comes with objects, not the map. You can force your impostor materials to conform to an ellipsoid with vertex calculations partially resolving the visual effect. However this won’t change the actual placement of objects on the map if they are placed with Collision.
I’m not sure what it is you are actually doing, so those are my considerations in relation to my project.
IF you are going for accuracy, modeling an ellipsoid is far more accurate from the start / Do not rely on the unreal maps/tiled world, or do the ground work to adjust their actual shape. You can totally make every tile bend somewhat correctly, it’s just an insane amount of work / It would be best to create a separate map system for it.