[pgrouting-users] PgRouting-Problems with own OSM-data
Stephen Woodbridge
woodbri at swoodbridge.com
Tue May 5 11:49:45 EDT 2009
Anton,
I added a detailed descriptions under the tools quick link:
http://pgrouting.postlbs.org/wiki/tools
-Steve
Anton Patrushev wrote:
> 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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