[pgrouting-users] Working with Driving Distance

Daniel Kastl daniel at georepublic.de
Tue Dec 21 23:43:26 EST 2010 

Hi Roger,

What OS do you use?
I haven't run Driving Distance function for a while and recently upgraded to
a newer version of Ubuntu.
In my case it says: ERROR:  function alphashape(unknown) does not exist

Might be that something has changed there with the dependent library (CGAL),
which is used to calculate the polygon.
I can't remember there was a problem in the past.

Daniel



2010/12/22 Roger André <randre at gmail.com>

> Ok, so using what I think is the correct SQL syntax, I get a different sort
> of error:
>
> eligibility=# SELECT the_geom FROM driving_distance('edges', 2512140,
> 7040129, 2000, 'length', 'length', false, false);
> NOTICE:  SRID: 2276
> NOTICE:  Query: SELECT gid, the_geom FROM points_as_polygon('SELECT
> a.vertex_id::integer AS id, b.x1::double precision AS x, b.y1::double
> precision AS y FROM driving_distance(''''SELECT gid AS
> id,source::integer,target::integer, length::double precision AS cost,
> length::double precision as reverse_cost FROM edges WHERE
> setsrid(''''''''BOX3D(2510140 7038129, 2514140 7042129)''''''''::BOX3D,
> 2276) && the_geom  '''', (SELECT id FROM
> find_node_by_nearest_link_within_distance(''''POINT(2512140
> 7040129)'''',200,''''edges'''')),2000,true,true) a, (SELECT * FROM edges
> WHERE setsrid(''''BOX3D(2510140 7038129, 2514140 7042129)''''::BOX3D,
> 2276)&&the_geom) b WHERE a.vertex_id = b.source')
> ERROR:  function find_node_by_nearest_link_within_distance(unknown,
> integer, unknown) does not exist
> LINE 1: ...)''::BOX3D, 2276) && the_geom  ', (SELECT id FROM find_node_...
>                                                              ^
> HINT:  No function matches the given name and argument types. You might
> need to add explicit type casts.
> QUERY:  SELECT a.vertex_id::integer AS id, b.x1::double precision AS x,
> b.y1::double precision AS y FROM driving_distance('SELECT gid AS
> id,source::integer,target::integer, length::double precision AS cost,
> length::double precision as reverse_cost FROM edges WHERE
> setsrid(''BOX3D(2510140 7038129, 2514140 7042129)''::BOX3D, 2276) &&
> the_geom  ', (SELECT id FROM
> find_node_by_nearest_link_within_distance('POINT(2512140
> 7040129)',200,'edges')),2000,true,true) a, (SELECT * FROM edges WHERE
> setsrid('BOX3D(2510140 7038129, 2514140 7042129)'::BOX3D, 2276)&&the_geom) b
> WHERE a.vertex_id = b.source
> CONTEXT:  PL/pgSQL function "points_as_polygon" line 17 at FOR over EXECUTE
> statement
> PL/pgSQL function "driving_distance" line 25 at FOR over EXECUTE statement
>
> Still puzzling this one out.
> --
>
>
> On Tue, Dec 21, 2010 at 7:55 PM, Roger André <randre at gmail.com> wrote:
>
>> Hi Daniel,
>>
>> Thanks for your reply.  I checked, and it appears that I have that wrapper
>> function installed.  Here is what my pgrouting install dir looks like:
>>
>> $ pwd
>> /usr/local/pgrouting-1.05/extra/driving_distance/sql
>>
>> $ ll
>> total 36
>> drwxr-xr-x 3 15036 users 4096 2010-12-21 15:58 ./
>> drwxr-xr-x 5 15036 users 4096 2010-12-21 15:58 ../
>> drwxr-xr-x 2 root  root  4096 2010-12-21 15:58 CMakeFiles/
>> -rw-r--r-- 1 root  root  1811 2010-12-21 15:58 cmake_install.cmake
>> -rw-r--r-- 1 15036 users  134 2010-11-16 18:42 CMakeLists.txt
>> -rw-r--r-- 1 root  root  5540 2010-12-21 15:58 Makefile
>> -rw-r--r-- 1 15036 users 1757 2010-11-16 18:42 routing_dd.sql
>> -rw-r--r-- 1 15036 users 3790 2010-11-16 18:42 routing_dd_wrappers.sql
>>
>> And I did make sure to run both SQL files against the database my roads
>> are stored in.
>>
>>   482  psql -d eligibility -f routing_dd.sql
>>   483  psql -d eligibility -f routing_dd_wrappers.sql
>>   490  psql -d eligibility -f routing_tsp.sql
>>   491  psql -d eligibility -f routing_tsp_wrappers.sql
>>
>> I will review your usage instructions and see if I'm missing anything.
>>
>> Roger
>> --
>>
>> On Tue, Dec 21, 2010 at 5:51 PM, Daniel Kastl <daniel at georepublic.de>wrote:
>>
>>> Hi Roger,
>>>
>>> You're using the "core" function, I think.
>>> You could use the driving_distance wrapper function, which will return
>>> you a polyogon.
>>> For that you need to load this SQL:
>>> https://github.com/pgRouting/pgrouting/blob/master/extra/driving_distance/sql/routing_dd_wrappers.sql
>>> You can also find it in the directory where the other pgRouting SQL files
>>> are.
>>>
>>> The function will take these parameters then:
>>>
>>> driving_distance(table_name varchar, x double precision, y double
>>> precision,
>>>         distance double precision, cost varchar, reverse_cost varchar,
>>> directed boolean, has_reverse_cost boolean)
>>>
>>> X,Y are the coordinates you take as a center point.
>>> You can take the returned polygon then and do other spatial queries.
>>>
>>> Best regards,
>>> Daniel
>>>
>>>
>>>
>>> 2010/12/22 Roger André <randre at gmail.com>
>>>
>>>> Hi All,
>>>>
>>>> I need to generate some maps that show all of the road segments that are
>>>> within a certain distance of specific points.  I have been able to generate
>>>> some answers using the driving_distance function, but am not sure what to do
>>>> with them.  Here's what I get:
>>>>
>>>> # SELECT * FROM driving_distance('SELECT gid AS id, source, target,
>>>> length::double precision AS cost FROM edges',49,2000,false,false);
>>>>  vertex_id | edge_id |       cost
>>>> -----------+---------+------------------
>>>>         15 |       9 | 1854.34547361565
>>>>         20 |     104 | 1549.85630678904
>>>>         22 |      68 | 858.367668935802
>>>>         23 |     125 | 1466.02479201359
>>>>         24 |      75 | 801.137871846872
>>>>         25 |     125 | 1169.02817170106
>>>>         26 |     106 | 1296.98197602289
>>>>         48 |      71 | 902.595810873304
>>>>         49 |     106 |                0
>>>>         51 |      74 | 1948.07551810288
>>>>         52 |      75 | 1620.93404864578
>>>> (11 rows)
>>>>
>>>> These answers seem legit, but I'm not sure what to do with them.
>>>> Ultimately, I need to show both the minimum enclosing polygon that
>>>> "surrounds" all of the road segments, as well as the road segments
>>>> themselves.  Can someone please give me some pointers as to what I can do to
>>>> accomplish this?
>>>>
>>>> Thanks,
>>>>
>>>> Roger
>>>> --
>>>>
>>>> _______________________________________________
>>>> Pgrouting-users mailing list
>>>> Pgrouting-users at lists.osgeo.org
>>>> http://lists.osgeo.org/mailman/listinfo/pgrouting-users
>>>>
>>>>
>>>
>>>
>>> --
>>> Georepublic UG & Georepublic Japan
>>> eMail: daniel.kastl at georepublic.de
>>> Web: http://georepublic.de
>>>
>>> _______________________________________________
>>> Pgrouting-users mailing list
>>> Pgrouting-users at lists.osgeo.org
>>> http://lists.osgeo.org/mailman/listinfo/pgrouting-users
>>>
>>>
>>
>
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-- 
Georepublic UG & Georepublic Japan
eMail: daniel.kastl at georepublic.de
Web: http://georepublic.de
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