[mkgmap-dev] Testing inter-tile routing with mapsource

Sat Feb 21 18:04:36 GMT 2009

On Sat, Feb 21, 2009 at 09:05:52AM +0100, Ralf Kleineisel wrote:
> Mark Burton wrote:
> 
> > Here's a thought off the top of my head. For optimal routing over long distances,
> > could the map also contain tiles that cover a larger area but with less detail?
> > Steve, Robert any thoughts on that idea?
> 
> When zooming out to, e.g. all of Germany, a cgpsmapper map is drawn very
> fast by my eTrex. A mkgmap map takes a much longer time. Both show
> motorways only. Perhaps there is really less data in the zoomed out tiles?

This post: http://www.mail-archive.com/qlandkarte-users@lists.sourceforge.net/msg00221.html
to the qlandkarte mailing list by Oliver contains several reason why mkgmap
maps are slow to draw in QLandkarte.  Its more than likely that these same
reasons apply to the device too.

A summary and comments on the ones that are relevent here:

1. The default style is very heavyweight and has many more levels than
   other maps.  We should have a style that has fewer levels for making
   large area maps.

2. Staircase lines in the outer zoom levels.  This is where smoothing would
   be really welcome.  I think (I could be wrong) that at the high zoom
   levels you will have to join the different parts of a road up before
   smoothing them (or something that has the same effect).

3. Motoway ramps.  I guess we can leave them out at outer zoom levels if
   it doesn't affect routing.

4. Lakes, forests at outer zoom layers.  We should have a way of leaving
   out smaller polygon features at outer zoom levels, while leaving in
   the larger ones.

..Steve