[mkgmap-dev] new option --add-boundary-nodes-at-admin-boundaries

Wed Aug 1 12:51:56 BST 2018

Gerd Petermann <gpetermann_muenchen at hotmail.com> writes:

> my understanding is this:
> The additional nodes (only) help when you create multiple maps. For example,
> if you have a script that creates a map for a given geofabrik extract by executing splitter and mkgmap.
> If you feed that script 1st with Maine and 2nd with New Hampshire you get two different maps
> with overlapping tiles.
> If you use osmconvert to merge the two extracts before using the script there are no overlapping tiles and
> thus there is no need for the additional nodes.

Thanks - that matches my understanding too.  What I meant is that long
long ago I was using multiple state extracts, and I think feeding them
into splitter together, and I found that I could not make cross-state
routes.  But that may work now because of geofrabrik itself being sure
to have matching nodes in adjacent extracts.

Based on that trouble, when us-northeast came out, I started using it,
since it was only 600 MB or so for the img, which was small enough not
to be a hassle.

I was thinking that it might be reasonable to process each US state to
produce an img, separately, and then to just load the ones you want.  So
people may want to try that out with
  --add-boundary-nodes-at-admin-boundaries=4
in the US.