User reported 'N at close tiles' and 'NS mirrored, EW reversed'.
With the canvas axes swapped:
- lng=+12 (corridor front in N flight) at canvas top -> screen
top -> ahead in flight direction (correct)
- perp<0 (world east) at canvas right -> screen right (correct)
Verifies user expectation: north tiles ahead (screen top), east tiles
to the right (screen right). N label appears at the far-ahead tiles
along the top of the screen, pointing forward in flight direction.
Richard Zink
bfe0a559b5