The red arrow on the local map points to geographic north. Movement follows the visible tile edges: numpad 7/9, 4/6, 1/3. The default grid-locked camera is a pure function of where you are standing — 4 and 6 always cross a near-vertical edge, and walking a loop returns you to exactly the orientation you left with, which parallel transport cannot do. Mode cycles it against the older traveller-up and north-up cameras.