On maps conflicts

Hope you can help clarify: I use splitter with option


to create pbf files with different map ids for each map I build.

I then use mkgmap to create maps with options

 --family-id="$familyid" --product-id=1

and using different family ids.

I also see mkgmap option


which seems to be necessary to avoid conflicts as per manual.

Question is, to avoid conflicts shall I alwasy create maps with different splitter’s mapid and different mkgmap’s family-id and different mapname or just one of them must be different?

Also, in case of multiple maps that overlaps the same area, I suppose I have to keep them selectively activated on my garmin device to avoid conflicts, or will they clash anyway? I tend to remember issues with address search.

I’m well aware of https://wiki.openstreetmap.org/wiki/OSM_Garmin_ID maintained by @ligfietser (thanks!) - but not sure that is the only item that needs to be unique.


Yes, AFAIK you have to make sure that each tile on your device has a unique mapname, no matter what family id is used.
The file template.args which is generated by splitter already contains the proper mapname options, so normally there is no need to set that option elsewhere.

Many thanks!

Any clue on multiple maps that overlaps the same area? Should I be safe if tile IDs are different, right?

It probably depends on the device. My Oregon for example doesn’t like transparent layers. They are displayed correctly but they slow down some POI searches drastically, e.g. the search for the nearby restaurants is unusable when I install a transparent layer of all cycle routes in Europe. Overlapping tiles can be a problem regarding routing. See mkgmap option --add-boundary-nodes-at-admin-boundaries=NUM for a possible solution.

Got it, thanks again!