Hi Steve,
I come back to you about about my query.
Do you have reproduced this problem ?
I would like to know if this problem will be resolved in next release?
thank you
Best regards
samuel
-----Message d'origine-----
De : pgrouting-users-bounces@lists.osgeo.org [mailto:pgrouting-users-bounces@lists.osgeo.org] De la part de Schembri Samuel
Envoyé : mardi 17 janvier 2012 11:27
À : pgRouting users mailing list
Objet : RE: [pgrouting-users] Different comportment between 'shortest_path_astar' and 'driving_distance' functions.
Hi Steve,
This is zip file with:
*Bug1.png You can see :
- Shortest_path function result : Green line
- Graph with digitalisation sens
- Id of vertex
- One way of 2 edges : red arrows
To go to vertex(48) since vertex (540), pgrouting is doing good choice because the edge (2: gid 51) has a big cost value . Full distance is 1159 meters.
*Bug2.png You can see :
- Driving distance result: blue labels and variant color : Distance ( meters)
- Edges used by pgrouting : blue line
- One way of 2 edges : red arrows
To go to vertex(48) since vertex(540), pgrouting takes the edge (2) with big cost value and he used reverse_cost value to calculate full distance.
Distance vertex must be egal to 1159.
*Dump with my graphe . (create a tif1104 schema before import)
Query:
select *
from shortest_path('
select
id
,source
,target
,cost
,reverse_cost,
to_cost
,rule
from
tif1104.graphe
where
statut is true
order by id',
540,
48,
false,
true )
select
*
from
driving_distance('
select
id
,source
,target
,cost
,reverse_cost
,to_cost
,rule
from
tif1104.graphe
where
statut is true
order by id',
540,
2000,
false,
true)
Best regards ...
Samuel
-----Message d'origine-----
De : pgrouting-users-bounces@lists.osgeo.org [mailto:pgrouting-users-bounces@lists.osgeo.org] De la part de Stephen Woodbridge Envoyé : lundi 16 janvier 2012 17:22 À : pgrouting-users@lists.osgeo.org Objet : Re: [pgrouting-users] Different comportment between 'shortest_path_astar' and 'driving_distance' functions.
On 1/16/2012 9:36 AM, Schembri Samuel wrote:
Hi steve,
Thank you for the response.
Why I would like to used this method. I prefer driving-distance
functions because when we must compute a lot of distances with same
departure point, this method is more fast than 'shortest_path_astar'
method. After, I can get distance with nodes directly.Example : get distance between shop and 100 customers.
Yes, this makes sense. I wrote some code a while ago that does some similar using driving distance code, but I did not check if the reverse cost were working.
I can create little graphe ,function, and snapshot.
How would you like receive these informations ?
If you want to generate a SQL dump of the above that would be great. If the results are simple enough to generate an expected results table so we can compare the actual results against the expected results that would be great, but if it is too complax than we can figure it out later.
Thanks,
-Steve
Regards
Samuel
-----Message d'origine----- De :
pgrouting-users-bounces@lists.osgeo.org
[mailto:pgrouting-users-bounces@lists.osgeo.org] De la part de Stephen
Woodbridge Envoyé : lundi 16 janvier 2012 15:14 À :
pgrouting-users@lists.osgeo.org Objet : Re: [pgrouting-users]
Different comportment between 'shortest_path_astar' and
'driving_distance' functions.Hi Samuel,
I'm not sure I can answer your question with doing some additional
research of reading through the code, but the driving directions does
not get much use and it is possible that it has a bug that noone has
reported until now.Your example seems like a really good test case. I am trying to
collect simple and clear test cases so we can develop a test suite
that can be run before we release code to validate changes in a
release have not broken anything. If you could create a ticket and
attach your test cases or just send them to me off list, I can create
a ticket for them.-Thanks, -Steve
On 1/16/2012 3:14 AM, Schembri Samuel wrote:
Hi, I am new user of this pgrouting users list. I hope used
correctly. I used pgrouting 1.02 on postgres 8.2.17. At this time, I
can't update Postgresql. There is a different comportment between
'shortest_path_astar' and 'driving_distance' functions when I use
reverse_cost column. Here are graphe conditions :* For each edge without one-way : cost=reverse_cost=length * For each
edge with one-way similar to digitalisation way : cost=length
reverse_cost=-1 (or 100000) * For each edge with one-way inverse of
digitalisation way : cost=-1 (or 100000) reverse_cost=length * All
another edges are not in graphe.*shortest_path_astar:* /has_reverse_cost = false : / Edges with
'cost=-1' are forbiden and Pgrouting don't used them.
'Reverse_cost' information is not used. /has_reverse_cost = true:/
Edges with 'cost=-1' are used if 'reserve_cost' is more than 0.
Cost used by pgrouting is 'reserve_cost' column. Edges with
'reverse_cost=-1' are used if 'cost' is more than 0. Cost used by
pgrouting is 'cost' column. T his computing is correct.
*Driving_distance:* ** /has_reverse_cost = false : / Edges with
'cost=-1' are forbiden and Pgrouting don't used them.
'Reverse_cost' information is not used. /has_reverse_cost = true:/
/Case one : Edge with 'cost=-1' and 'reverse_cost=length' Edge can
be traveled on digitalisation way ( cost =-1!!). Cost used by
pgrouting is 'Reverse_cost' column. /Case two : Edge with cost=length
and reverse_cost=-1:/ Edge can be traveled on inverse digitalisation
way. More, Cost used by pgrouting is 'cost' column.
In this two case, pgrouting don't respect restrictions. This
computing is not correct. Could you me if this result is normal or
not ? Sorry for my bad english and best regards Samuel -- Paris //_______________________________________________ Pgrouting-users
mailing list Pgrouting-users@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/pgrouting-users_______________________________________________ Pgrouting-users
mailing list Pgrouting-users@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/pgrouting-users
_______________________________________________ Pgrouting-users
mailing list Pgrouting-users@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/pgrouting-users
_______________________________________________
Pgrouting-users mailing list
Pgrouting-users@lists.osgeo.org
http://lists.osgeo.org/mailman/listinfo/pgrouting-users
pg.zip (184 KB)
ATT00001.txt (169 Bytes)