[pgrouting-users] Problem using TRSP
Christy Nieman
cnieman at dmsolutions.ca
Thu Aug 30 08:27:27 PDT 2012
I'll see if I can come up with a simple test case that demonstrates
this. I think it's taking the "wrong" route, but it may possibly be a
route of lower cost than the other two algorithms are using. I'll look
into that too.
Christy
On 08/30/2012 11:22 AM, Stephen Woodbridge wrote:
> On 8/30/2012 11:08 AM, Christy Nieman wrote:
>> All,
>>
>> I'd just like to note that I have noticed this too, and it only seems to
>> happen for me if I'm not using a directed graph (e.g. reverse_cost and
>> the two booleans to true).
>
> Tao, make sure you try your graph with a directed graph.
>
>> TRSP also seems to not calculate the same routes as A-Star or Dijkstra
>> if not using a directed graph.
>
> It is possible that there are multiple paths with the same length, in
> which case the result will vary depending on the algorithm sets up the
> queue. If you are say that it is compute the "wrong" route as in there
> is a shorter route if you are not applying restriction. then you
> should probably create a simple test case and fill it with a bug so we
> can look into it.
>
> -Steve
>
>> Christy
>>
>> On 08/30/2012 07:32 AM, Tao Romera Martinez wrote:
>>> Can you think of anything I could try to find the source of the
>>> problem?
>>>
>>> 2012/8/24 Tao Romera Martinez <taoromera at gmail.com>:
>>>> Sorry, Stephen, this did not fix the problem. I still have 0 in the
>>>> cost column.
>>>>
>>>> 2012/8/23 Stephen Woodbridge <woodbri at swoodbridge.com>:
>>>>> Try renaming column "cost" and see if the fixes it.
>>>>>
>>>>> alter table japan rename column cost to old_cost;
>>>>>
>>>>> Let us know if this fixes the problem, because it means we have a
>>>>> bug.
>>>>>
>>>>> You can rename the column back the way it was with:
>>>>>
>>>>> alter table japan rename column old_cost to cost;
>>>>>
>>>>> Thanks,
>>>>> -Steve
>>>>>
>>>>>
>>>>> On 8/23/2012 2:06 AM, Tao Romera Martinez wrote:
>>>>>> Hello Stephen,
>>>>>>
>>>>>> Thank you very much for your quick answer.
>>>>>> The query you asked to me to run gives some rows with cost_car=0,
>>>>>> but
>>>>>> none of them is in the list of edges returned by
>>>>>> turn_restrict_shortest_path.
>>>>>> Here is the query result with the cost_car for each edge:
>>>>>>
>>>>>> vertex_id | edge_id | cost | cost_car
>>>>>> -----------+---------+-------------------------------------
>>>>>> 284867 | 211472 | 0 | 0.07751676
>>>>>> 284794 | 211471 | 0 | 0.2359118
>>>>>> 134058 | 205895 | 0.15 | 0.14653888
>>>>>> 284826 | 205894 | 0 | 0.042989656
>>>>>> 131290 | 205893 | 0 | 0.074959315
>>>>>> 127938 | 201505 | 0 | 0.054259572
>>>>>> 132923 | 201504 | 0 | 0.022826955
>>>>>> <...>
>>>>>> 282198 | 425307 | 0 | 0.07132499
>>>>>> 282197 | 795399 | 0.021921627 | 0.021921627
>>>>>> 282276 | 795400 | 0.05221079 | 0.05221079
>>>>>> 282035 | 425170 | 0.15 | 0.0967519
>>>>>> 282034 | -1 | 0 | -
>>>>>>
>>>>>> I am eager to try to find the reason of this strange behaviour, so
>>>>>> tell me if there is anything I can do to figure it out.
>>>>>>
>>>>>> Best regards,
>>>>>>
>>>>>> Tao
>>>>>>
>>>>>> 2012/8/20 Stephen Woodbridge <woodbri at swoodbridge.com>:
>>>>>>> Please keep the queries on the list.
>>>>>>>
>>>>>>> No, I have no idea, I've never seen anything like that before.
>>>>>>>
>>>>>>> What does this query return?
>>>>>>>
>>>>>>> select count(*) from japan where cost_car=0;
>>>>>>>
>>>>>>> -Steve
>>>>>>>
>>>>>>>
>>>>>>> On 8/20/2012 7:26 AM, Tao Romera Martinez wrote:
>>>>>>>>
>>>>>>>> Dear Stephen,
>>>>>>>>
>>>>>>>> I have been trying to use your function for turn restricted
>>>>>>>> shortest
>>>>>>>> path routing.
>>>>>>>> I installed the postgresql functions, prepared a table with the
>>>>>>>> turn
>>>>>>>> costs, and now I am able to route through a network using turn
>>>>>>>> restrictions. Well, almost.
>>>>>>>>
>>>>>>>> When I launch a request, the column "cost" contains 0 values
>>>>>>>> except
>>>>>>>> for the rows where there is a turn (the cost is the one set for
>>>>>>>> turns).
>>>>>>>> The request is:
>>>>>>>>
>>>>>>>> SELECT * FROM turn_restrict_shortest_path(
>>>>>>>> 'SELECT id AS id, source::integer, target::integer, cost_car AS
>>>>>>>> cost
>>>>>>>> FROM japan WHERE japan.geom_way && ST_MakeEnvelope(139.675,
>>>>>>>> 35.729,
>>>>>>>> 139.705, 35.762)',
>>>>>>>> 284867, -- node_id of start
>>>>>>>> 282034, -- node_id of end
>>>>>>>> false, -- directed graph?
>>>>>>>> false, -- has_reverse_cost?
>>>>>>>> 'SELECT to_cost::double precision, teid::integer AS target_id,
>>>>>>>> feid||coalesce('',''||via,'''') AS via_path FROM turn_costs WHERE
>>>>>>>> teid
>>>>>>>> IN (select id FROM japan WHERE japan.geom_way &&
>>>>>>>> ST_MakeEnvelope(139.675, 35.729, 139.705, 35.762)) ');
>>>>>>>>
>>>>>>>> The ST_MakeEnvelope is just to create a window and limit the
>>>>>>>> otherwise
>>>>>>>> huge amount of ways.
>>>>>>>>
>>>>>>>> The table "japan" looks like:
>>>>>>>>
>>>>>>>> id | osm_id | osm_name | osm_source_id | osm_target_id |
>>>>>>>> clazz |
>>>>>>>> flags | source | target | km | kmh | cost | reverse_cost | x1 |
>>>>>>>> y1 |
>>>>>>>> x2 | y2 | geom_way | cost_car
>>>>>>>>
>>>>>>>>
>>>>>>>> ----+---------+----------+---------------+---------------+-------+-------+--------+--------+-----------+-----+-----------+--------------+----------+------------+-------------+------------+----------------------------
>>>>>>>>
>>>>>>>>
>>>>>>>> 1 | 4847506 | | 31236733 | 31236584 |
>>>>>>>> 11 |
>>>>>>>> 1 | 24690 | 24758 | 1.6335903 | 1 | 6.5343612 | 1.6335903 |
>>>>>>>> 139.7578 | 35.6437952 | 139.7688252 | 35.6349433 | <snip> |
>>>>>>>> 3.2671806
>>>>>>>>
>>>>>>>> And the table "turn_costs" looks like:
>>>>>>>>
>>>>>>>> rid | to_cost | teid | feid | via
>>>>>>>> -----+---------+--------+------+-----
>>>>>>>> 1 | 0.15 | 22 | 10 |
>>>>>>>> 2 | 0.15 | 21 | 10 |
>>>>>>>> 3 | 0.15 | 163 | 10 |
>>>>>>>> 4 | 0.15 | 27 | 10 |
>>>>>>>> 5 | 0.15 | 26 | 10 |
>>>>>>>> 6 | 0.15 | 27 | 11 |
>>>>>>>> 7 | 0.15 | 26 | 11 |
>>>>>>>> 8 | 0.15 | 229 | 11 |
>>>>>>>> 9 | 0.15 | 232698 | 11 |
>>>>>>>> 10 | 0.15 | 229 | 12 |
>>>>>>>>
>>>>>>>> The result of the query looks like:
>>>>>>>>
>>>>>>>> vertex_id | edge_id | cost
>>>>>>>> -----------+---------+-------------
>>>>>>>> 284867 | 211472 | 0
>>>>>>>> 284794 | 211471 | 0
>>>>>>>> 134058 | 205895 | 0.15
>>>>>>>> 284826 | 205894 | 0
>>>>>>>> 131290 | 205893 | 0
>>>>>>>> 127938 | 201505 | 0
>>>>>>>> 132923 | 201504 | 0
>>>>>>>> <...>
>>>>>>>> 282198 | 425307 | 0
>>>>>>>> 282197 | 795399 | 0.021921627
>>>>>>>> 282276 | 795400 | 0.05221079
>>>>>>>> 282035 | 425170 | 0.15
>>>>>>>> 282034 | -1 | 0
>>>>>>>>
>>>>>>>> Do you have an idea about why the "cost" values are 0?
>>>>>>>>
>>>>>>>> Thank you very much for your help,
>>>>>>>>
>>>>>>>> Tao
>>>>>>>>
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>>>>>>
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