[pgrouting-users] PgRouting-Problems with own OSM-data

[Kai Behncke]

Dear users,

maybe the following screenshot helps fo find out what is wrong with my geodata:


http://www.selbstverwaltung-bundesweit.de/weird_numbers.png



The three numbers (blcak on grey backround) show the gid of the geometry,the source-id and the target-id.

The blue figure shows the id of the vertices (no dead end) and the red number is the number of the dead-end-vertices.

As you cann see some are correct and some are not.
This should happen at SELECT assign_vertex_id('my_table', 0.001, 'the_geom', 'gid');


....but why? I cant`t see the system of that failure?

Best regards, Kai
-------- Original-Nachricht --------
> Datum: Sat, 18 Apr 2009 00:57:30 +0200
> Von: "Kai Behncke" <Kai-Behncke at gmx.de>
> An: Stephen Woodbridge <woodbri at swoodbridge.com>, pgrouting-users at lists.postlbs.org
> Betreff: Re: [pgrouting-users] PgRouting-Problems with own OSM-data

> Hi Stephen, Hi mailinglist,
> 
> thank you very much for that hint. With that way I was able to find out
> that there are far too many "dead ends" in my data, so I think this is the
> proof that it`s really a data problem?
> 
> http://www.selbstverwaltung-bundesweit.de/too_many_dead_ends.png
> 
> I made this test also with the victoria-data, there everything is correct.
> 
> To get a step further I work now with a very small dataset (just 35
> geometries) (as you can see in the screenshot above) but without success
> so far.
> 
> >If you have a lot of red dots between segments
> >that should be joined, you probably need to rebuild your vertices tmp
> >table with a larger tolerance.
> 
> I did that, I changed 0.001 in
> 
> SELECT assign_vertex_id('auswahl_os', 0.001, 'the_geom', 'gid');
> 
> with the values 0.005, 0.01, 0.05, 0.5, 5, 50 and so on
> 
> The values <50 still show very many "dead ends". If I have higher values
> then
> the amount of vertices in general decreases, so a routing is also not
> possible anymore, you can see it here:
> 
> 
> http://www.selbstverwaltung-bundesweit.de/not_enough_vertices.png
> 
> 
> Maybe the following is a hint:
> 
> If I use
> SELECT assign_vertex_id('auswahl_os', 0.001, 'the_geom', 'gid');
> 
> with my data I get 54 entries in the vertices_tmp-table.
> (an extract of the victorie-data (50 geometries) just gives 42 entries in
> vertices_tmp).
> 
> What could be the reason that I get so many entries mith my data?
> 
> What exactly stands the value 0.001 for?
> 
> I really don`t understand what could be wrong with my geodata :-(
> 
> Might it be possible that someone would have a look to these 54 geometries
> (4 eyes see more than two) ??
> 
> Puh....if I get it I will really write a huge tutorial in the
> pgrouting-wiki.
> 
> Best regards, Kai
> 
> 
> 
> -------- Original-Nachricht --------
> > Datum: Wed, 15 Apr 2009 13:24:21 -0500
> > Von: Stephen Woodbridge <woodbri at swoodbridge.com>
> > An: Kai Behncke <Kai-Behncke at gmx.de>
> > CC: pgrouting-users at lists.postlbs.org
> > Betreff: Re: [pgrouting-users] PgRouting-Problems with own OSM-data
> 
> > Kai,
> > 
> > First off you probably need to build some diagnostic tools to help you 
> > understand the problem better, especially to help you determine if it is
> > a data problem. I find two tools that are easy to build and help a lot. 
> > You can see them in action here:
> > http://imaptools.com/leaddog/routing/dd.html
> > Zoom into a city, open the layerswitcher and select "Just the Streets" 
> > and "Dead Ends"
> > 
> > 1) create a mapfile that displays the street segments from the routing 
> > database and add this as an optional base layer. You might want to add 
> > color oneway streets a different color, but in general keep the display 
> > simple and probably single pixel lines. You might label the segments 
> > with their UID so you can go back to the database and query them in
> > detail.
> > 
> > 2) add a column cnt integer to the vertices_tmp table and update it with
> > the count of segments that reference that node. Maybe something like
> this:
> > 
> > alter table vertices_tmp add column cnt integer;
> > update vertices_tmp set cnt=0;
> > update vertices_tmp set cnt=cnt+1 where streets.source=id;
> > update vertices_tmp set cnt=cnt+1 where streets.target=id;
> > 
> > Now create a mapfile layer for points and display the vertices_tmp
> > 
> > LAYER
> >    NAME "deadends"
> >    TYPE POINT
> >    CONNECTIONTYPE "postgis"
> >    CONNECTION ...
> >    DATA ...
> >    CLASSEXPRESSION "cnt"
> >    CLASS
> >      EXPRESSION "cnt=1"
> >      STYLE
> >        SYMBOL "circle"
> >        SIZE 5
> >        COLOR 255 0 0
> >      END
> >    END
> >    CLASS
> >      EXPRESSION "cnt>2"
> >      STYLE
> >        SYMBOL "circle"
> >        SIZE 3
> >        COLOR 0 255 0
> >      END
> >    END
> > END
> > 
> > This will display red dots at dead ends and green dots as good 
> > connections be segments. If you have a lot of red dots between segments 
> > that should be joined, you probably need to rebuild your vertices tmp 
> > table with a larger tolerance.
> > 
> > It is very hard to debug a large black box like a router without having 
> > some tools that can give you some better insight as to what is going on.
> > 
> > -Steve
> > 
> 
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