That last especially is good Treetop64. Historically speaking of the modding of SH4, and probably 3 at the time, it was discovered that the crewmembers of your submarine (and probably other vessels), can see "through" the horizon and call out "Ship spotted, bearing..." So "flattening" the curve of the earth allows the player to "see" what the AI "sees". CapnScurvy speaks to this in his
Optical Targeting Correction (OTC) mod's documentation.