[pgrouting-users] Get the edges in correct order

[ancaag04 at alumnos.unex.es]

I found that the failure depends on the size of the imported topology.

For example, if the database has 2000 or 1800 edges (or less), the order is correct.
But if the database has 4000 or 6000 edges (or more), the order is wrong (is ordered
automatically by gid).

I do not know why this happens... I have not modified any function.

-Antonio




> Hi Antonio,
>
> I'm not sure, but I did notice that your list of segments appears to be
> ordered by gid. You might want to check if the function shootingstar_sp
> has been modified and someone who added an "order by gid" clause to it.
>
> -Steve
>
> On 9/7/2011 11:35 PM, ancaag04 at alumnos.unex.es wrote:
>> Hello Steve, I know the discussion, but the problem is different.
>> For example, this image [1] shows a part of the city. I have marked the start and
>> end edges.
>>
>> Now I have this query:
>>
>> SELECT gid, AsText(the_geom) AS the_geom
>>          FROM shootingstar_sp('ways', 552, 1096, 0.1, 'length', true, true);
>>
>>
>> This image [2] shows the results.
>>
>> [1] http://img828.imageshack.us/img828/7915/segments.png
>> [2] http://img215.imageshack.us/img215/5103/resultsi.png
>>
>>
>> I'm doing something wrong?
>> Thank you.
>>
>> --
>> Antonio
>>
>>
>>
>>> On 8/31/2011 11:28 PM, ancaag04 at alumnos.unex.es wrote:
>>>> Hello, i'm using A-star like this:
>>>>
>>>> SELECT gid, AsText(the_geom) AS the_geom
>>>> FROM astar_sp_delta('ways', 2124, 2168, 0.1);
>>>>
>>>> The path is correct but sometimes I don't get the edges in the correct order.
>>>> Is this normal?
>>>
>>> I think the edges are always in the correct order, but some times the
>>> edge is reversed from the direction that you traverse it on the route.
>>> This has been discussed in the past and I have posted an algorithm to
>>> correct that, but I do not have a link to it handy.
>>>
>>> -Steve
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>>
>>
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