[mkgmap-dev] [PATCH v1] - Route centre tweaks

Tue Sep 22 14:08:23 BST 2009

Felix,

> After playing around a bit on my Vista HCx I did notice slightly 
> different routing too. The maximum distance that it manages without 
> "route calculation error" did not change however.

On the HCx, I just tried an 800Km route from where I live to Thurso and
it took quite a while (stuck on 100% for a minute or two) but it did
eventually calculate a sensible route.

> > Today's offering includes the table A tweak but it also increases one
> > of the limits that determine when a route centre needs to be
> > sub-divided. As far as I can tell, the limit was somewhat smaller than
> > it should have been. So with this patch, fewer routing centres should
> > be required (obviously depends on the map data).
> Routing in Mapsource is now different too. So far I have found one route 
> that does not calculate with the old version, but with the new. The 
> difference is however 2-3 more turns, so no drastical improvement. Maybe 
> some routes also degrade?

I guess that is possible but I would hope that the overall effect is
beneficial. I'm (optimistically) working on the theory that increasing
the size of the route centres makes the route calculation
easier/quicker. That could, of course, be complete rubbish.

With the current patch, my GB map is around 172 MB compared to 180
without so the space saving is worth having if not dramatic.

Cheers,

Mark