[mkgmap-dev] Commit: r1265: Added --drive-on-left, --drive-on-right and --check-roundabouts options.

Tue Oct 20 14:37:11 BST 2009

On Tue, Oct 20, 2009 at 02:17:39PM +0100, Mark Burton wrote:
> > I did not find the old discussion on a problematic roundabout, so I cannot
> > check the data.  I am just guessing that the problem could be that the
> > roundabout segments were not tagged junction=roundabout (because some
> > validator or renderer could have problems with roundabouts defined in
> > multiple segments).  That would be an error of the validator or renderer,
> > of course.
> 
> Splitting roundabouts into segments is very common in the UK because
> of route relations. i.e. a bus route uses part of a roundabout and so
> the roundabout is split into segments so that only a portion of the
> roundabout is part of the bus route.

Same here.  I did see warnings about roundabout sections.  I fixed one
set of these close to Ivalo.  There were some "forward" and "backward"
relations of these int_ref=E75 roads.  It apparently is a dual carriageway
(two oneway streets) between roundabouts.  Both oneways were running from
south to north. :-(

> You may also wish to try out the new --check-roundabout-flares option
> which checks that roundabout flare roads are sane (oneway, point in the
> right directions and don't extend further than they need to).

Thanks, I think I will try to outsource the job in the Finnish community,
possibly by posting a note or link on my map download page
http://www.polkupyoraily.net/osm/.

> For the GB data, enabling that test gives over 2000 warnings, the vast
> majority of which are real problems that either break the routing
> completely or at least give odd routes. I am (slowly) editing the
> OSM data to fix the problems. It's incredible what crap people are
> happy to put into the OSM database. I get the impression that most
> contributors don't give a toss about the map being routable or not.

Right.  I have seen the same here.  Missing bridges or tunnels, missing
junctions or bridges between railway and highways, missing junction nodes,
overlapping roads, and so on.

We can only hope that the availability of OSM-based mobile routing systems
will create some incentive to fix this.  On the Finnish OSM forum, there
has been some discussion that GpsMid and PhoneME work on dime-a-dozen
Windows CE based car navigators.  Alas, routing in GpsMid is said to be
very slow.  (I do not have any first-hand experience, I am only repeating
what I read.)  Until there is an open-source mobile routing platform, mkgmap
will remain relevant.  I believe that it could take several years.  I hope
that my Edge 705 will last so long. :-)

	Marko