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

Sun Apr 19 21:50:47 EDT 2009

Kai, Steve,

It sounds like a very good example of data validation and for sure
will be interesting for other users.
Can someone of you please put it to pgRouting wiki?

Anton.

On Sat, Apr 18, 2009 at 8:25 PM, Kai Behncke <Kai-Behncke at gmx.de> wrote:
> 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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