[pgrouting-users] Try to use pgRouting and driving_distance function to do special routing task

[Heinz Chen]

Thank you for your helpful suggestion!
I have used pgRouting algorithm to do this, and got the product I want.


2014-04-24 21:53 GMT+08:00 陳彥文 <r01622040 at ntu.edu.tw>:

> Thank you for your helpful suggestion!
> I have used pgRouting algorithm to do this, and got the product I want.
>
>
> 2014-04-18 21:22 GMT+08:00 Stephen Woodbridge <woodbri at swoodbridge.com>:
>
> On 4/18/2014 6:35 AM, Heinz Chen wrote:
>>
>>> Hello, guys, I don't know how to use pgRouting and driving_distance to
>>> do this special routing, the details I have posted in this forum,
>>>
>>> Use PostgreSQL to route in different style
>>> <http://stackoverflow.com/questions/23098554/use-postgresql-to-route-in-
>>> different-style>
>>>
>>>
>>> Can I just achieve this goal just using pgRouting and driving_distance？
>>> Or is there another way to do this？
>>> Please give me some hint to begin with and feel free to give me any
>>> suggestion, thanks!
>>>
>>
>> I looked at your question and I don't think you can do it with the
>> existing driving distance code. You might be able to modify the existing
>> code to get it to do what you want. The way the code works is this:
>>
>> 1. we build a graph from the edges
>> 2. we solve the graph using dijkstra's algorithm based on the start node
>> 3. this creates a tree off shortest paths with the start node the root of
>> the tree
>> 4. we walk the tree summing the edge lengths from the root to each node
>> and emit all the nodes.
>>
>>
>> For your case you would what to change step four generate a product of
>> the edge lengths. I looked briefly at the code but could not spot where the
>> cost summing was happening, but it should be reasonable obvious.
>>
>> If you don't need all cost to all nodes, ie the cost from the start to a
>> specific end node then you can use pgr_dijkstra and that will return all
>> edges for that shorest path and then you can generate the product from that.
>>
>> -Steve
>>
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>
>
>
>
> --
> 生工所 r01622040 陳彥文
>
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