[mkgmap-dev] problems at map intersections?

Sat Jul 18 00:02:10 BST 2009

Hi Mark,

Mark Burton schreef:
> I believe (because the ML is not showered with emails complaining about
> it failing) that inter-tile routing is generally working OK.

It really does work great. In fact, it took me quite a while to come to
the conclusion that the map edge seemed to be involved and that there
might be a routing problem after all. At first I thought it was the
tagging of tunnel, the fact that I tried to send a bike through a
tunnel, the fact that I chose a bicycle for routing at all (Garmin
doesn't do a really good job there - or maybe they like biking so much
that they send you for 30 kilometer trips when 11 could do). But a few
days ago I noticed that the map dissapeared at the same spot where the
routing went wrong when I biked around with my Garmin Nuvi.

Oh, and yes: I really think there aren't enough people riding around on
their bicycles at OSM/splitter map edges, while looking at their Garmin
Nuvis loaded with Openstreetmap-data in "Driving Direction Up" (i.e.
non-3D), "Highest Detail", "Highest zoom" mode. I really should start a
support group ;-)

> Please provide an example of it failing so we can study it.

memory=1700m
maxn=500000
wget 'http://download.geofabrik.de/osm/europe/netherlands.osm.bz2'
bzcat netherlands.osm.bz2 > netherlands.osm
wget 'http://www.mkgmap.org.uk/snapshots/mkgmap-latest.tar.gz'
tar -zxf mkgmap-latest.tar.gz
wget 'http://www.mkgmap.org.uk/splitter/splitter.jar'
java -Xmx$memory -jar ./splitter.jar --max-nodes=$maxn netherlands.osm
java -enableassertions -Xmx$memory -jar mkgmap*/mkgmap.jar \
  --country-name=Nederland --country-abbr=NL --latin1 \
  --remove-short-arcs --lower-case --route --preserve-element-order \
  --location-autofill-1 --gmapsupp --net 63240008.osm.gz 63240010.osm.gz

Then load the resulting map in MapSource; to be sure, select
Edit-Preferences-Routing, Bicycle, shortest distance. (Set detail to
Highest if you want to see the biking path).

Then route from N52.42701 E4.82707 to N52.42625 E4.82736, they are on
the same biking path, some 80 metres apart. You'll see the route deviate
3 kilometers.

Also, if you try to zoom on one of the points above, you'll see a blank
map. (This is Mapsource 6.11.5 running under Wine, but as said before:
my Garmin Nuvi does the same - only on highest zooming level though, and
only around the edges on the OSM map - it does not do that on the Garmin
native map - I did check that).

I hope you can reproduce my findings - that would be a help.

Thanks so far, best regards,

Valentijn
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