[mkgmap-dev] Inter-tile routing failures - not all our fault?

Fri Aug 14 11:34:10 BST 2009

Using a recent GB tiled map on my eTrex, I have found that it performs
differently (better?) to mapsource with regard to the problem of not
routing across a boundary and back to the source tile.

An example route I tried used a road that snaked across a boundary.
Mapsource failed miserably in the manner previously described. The
eTrex faired better in that it could manage to route across the
boundary and back again for at least one crossing pair but when I tried
to cross and back again for the second time, it took a really long time
to calculate the route and the result was very silly.

On another example route, that crossed the boundary to a fork and then
crossed back to the original tile, mapsource failed but the eTrex was
quite happy.

So I remain far from convinced that the problem is due to buggy map
data generated by mkgmap. However, it may be that we have to generate
map data that is in some way "more sympathetic" to the needs of the
Garmin routing engines.

Mark