I initially thought I'd say that OT's system is closer to Infinity's, but reading it more attentively I see that theirs is a lot simpler and limiting (but it's an ancient text, here's a recent update about
Infinity's planetary engine enhancements).
So actually it would be better to take the PA's virtual texturing as the basis for explanation.
In OT the similarities are that there's something like a "resolver" that determines what LOD is needed where for terrain tiles. Technically it does the same thing: computes what texture resolution is needed for terrain chunks, based on an indirect screen-space metrics. Missing tile textures are the generated dynamically from terrain data - well, actually the terrain data are generated first, since these are procedural too. The texturizer arose from a system similar to Infinity's, taking altitude and slope into the account. Nowadays it's taking a lot more parameters into the decision process: latitude, filtered terrain curvature and slope, additional fractal channels, data from the vector overlay etc. Biomes will expand it a bit too.
