mkgmap - routing between points at two or more maps (countries)


I’m tryging to prepare some maps of European countries (Poland, Czech, Germany, Slovakia…). I don’t need entire Europe in one map - I prefer to have maps of each country and enable/disable those which are currently needed.
My problem is routing. Rounting internally at each country map working good but when I try to route between 2 countries (same border) - for example Czech and Poland my unit (Garmin Montana 600) stop calculating route at some % (I assume - reaching the border).
Could You please give me some advice or even better - example to prepare working set of maps?
I’m using Geofabrik OSM data, splitter and mkgmap.


In mkgmap maps I have seen problems with long distance routing (> 800~900 Km)
To check for continuity try to simulate the route between two points only a few Km of each side of the border.

Here you have how this South America map is prepared.

That won’t work. You must have one map containing both countries in order for border-crossing routing to work.
It is possible to combine the Geofabrik extracts and then create the map from that combined file.

So only way is to use larger area (several countires) in one map?
This is due limitation of mkgmap or splitter?

No sure, but i supose is not mkgmap or splitter fault, just that in Garmin map format the road networks of different maps are not connected.

¿What happens with official Garmin maps?

Just saw a new post on the mkgmap mailing list addressing this issue:
Let’s wait and see if our masters of Garmin map creation can find a solution (but I doubt that it is possible at all).

They are working in a solution.

A new option --add-boundary-nodes-at-admin-boundaries was added with mkgmap version r4223.

Hi Gerd,

Your work on mkgmap is very appreciated! Thanks.

I saw the commits, and it seems that this will be the default behaviour from r4223.
Should we expect that map producers which uses that version or newer, and the map and their users should benefit without doing nothing?