[mkgmap-dev] [PATCH v4] - min arc length fixes

Fri Aug 14 16:18:20 BST 2009

On Fri, Aug 14, 2009 at 2:44 PM, Greg Troxel<gdt at ir.bbn.com> wrote:

> I most recently built with all 6 NE states (conn, ri, mass, vermont, new
> hampshire, maine) all together, invoking the script 'do-mkgmap' which
> follows as something like
>
> $ do-mkgmap *.osm.bz2

In this case, routing will not work across state boundaries. You know
that though, right?

I compiled Massachusetts and experimented with routing in Mapsource (I
will try Roadtrip later). I found that routing only works for very
short distances (even without crossing tile boundaries). For example,
I tried the I95 around Boston. There, I could only route along
segments which were less than 1 km long.

It seemed, although I have not tested enough to confirm, that it was
hardest routing along the more curved sections of highway. This would
support the hypothesis that the node density is too high for proper
routing. I have not had time to download the OSM data to take a look.
I wonder if a way simplification patch could help here.

I'm surprised that you were able to create routable maps using
--max-nodes=1600000. I had to lower max nodes to 800000 in order to
compile.

Cheers.