[mkgmap-dev] tile size?

Fri Mar 20 12:23:49 GMT 2009

Hi Lambertus,

On Fri, Mar 20, 2009 at 09:12:01AM +0100, Lambertus wrote:
> North and South America split fine with max-nodes set to 120000. Europe  
> still gives a few errors with that setting though. See the results of a  
> complete world splitted with the 120000 setting here:  
> http://garmin.na1400.info/routable.html
>
> I plan to split the remaining failed tiles manually.

Are you planning to fine-tune the tile division by hand?  If so, I would
suggest that you avoid splitting South Finland or North Estonia in the
west-east direction.  Given that there could be some inter-tile routing
issues (suboptimal routes chosen), it would be better to have a tile border
on the Baltic sea between Finland and Estonia.

I don't care which tile the Åland islands are on; they are roughly
halfway between Sweden and Finland anyway.  Although they belong to
Finland, they are autonomous and tightly connected with Sweden.

For what it is worth, my Finnish Garmin map generated from finland.osm.bz2
at http://www.polkupyoraily.net/osm/ uses this areas.list:

63240001: 2768896,890880 to 2916352,1472512
#       : 59.414063,19.116211 to 62.578125,31.596680
63240002: 2916352,890880 to 3020800,1472512
#       : 62.578125,19.116211 to 64.819336,31.596680
63240003: 3020800,890880 to 3266560,1472512
#       : 64.819336,19.116211 to 70.092773,31.596680

The reasoning is that most of the population is located in the south,
and therefore the south must be a single tile.

Similarly for Estonia, most population should be in the mainland, near
Tallinn.  You could put the Saaremaa and Hiiumaa islands on a separate
tile without losing any routing functionality.

I hope that you consider this suggestion.  If it works out well, I'd
like to set up a mirror to your map tiles instead of generating the
tiles myself.  (I only have a 32-bit machine on a 1 Mb/s ADSL line.)

	Marko