Navigation in all directions is now working, but raises a design decision: what should happen when you're at the top of the map and click North? There are several possibilities:

1. stay where you are
2. loop around to the bottom of the map at the same longitude so that subsequent hits on North will take you back where you started.
3. leap over the pole and arrive at the top of the map, 180 degrees of longitude away on the other side of the world.

3 might make the most sense in terms of navigation, but it could be confusing. Repeatedly clicking North will alternate between two tiles at the same latitude but 180 apart in longitude.

The problem arises because at the north pole it's impossible to go any further north - we don't have the pole to show so we've got no framework in which to tell the user that. Option 3 isn't really any more "accurate" as your destination is probably at exactly the same latitude as your starting point.

The same problem arises with north-east, north-west etc. I've gone for option 2, where the indicated directions are accurate for all but the north/south boundary cases and you can cycle around the whole earth by following the same direction. Will take user feedback and see what people think.

T
- posted by Tim Bruce @ 12:17 PM