[PvK]

It's the point where a straight line from the origin system enters the destination system, based on the quadrant map. No randomness, but how exactly it rounds to one sector or the other may be hard to predict without trying it, or trying a test game, or looking at natural warp points between systems which have the same orientation between them (though it's possible that there are rounding artifacts depending on which direction the warp line is generated from, I don't remember ever noticing that).

PvK