[postgis-users] PgRouting in PostGIS

[Stephen Woodbridge]

Stephen Woodbridge wrote:
> Nandorov wrote:
>> can i block some segments? for example cad gives the posibility to put 
>> a max
>> resistance value, let's say it's 100. So if the resistance of your 
>> segment
>> is 100 that segment is blocked and you cannot go thorught this way. if 
>> this
>> possible with pgrouting?
> 
> Yes you can put a high cost on a segment and then it will search for a 
> lower cost alternative soultion. In routing you can also have a reverse 
> cost that is the cost to traverse the segment from end to start as 
> opposed to the cost which is for traversing from start to end. You can 
> also just have a single cost that is good for either directions. We use 
> high costs to prevent routing the wrong way down one way streets.
> 
> Routing solutions from a single best path. There exist different network 
> analysis algorithms for doing things like water flow analysis and things 
> like that.

To clarify this should have said:

Routing solutions form a single best path. There exist different network
analysis algorithms for doing things like water flow analysis and things
like that, but pgRouting does not support these.

-Steve W.

> -Steve W
> 
>> thanks!
>>
>>
>> Stephen Woodbridge wrote:
>>> Nandorov wrote:
>>>> hi,
>>>> i've tried pgrouting algorithms and works pretty well. However, i dont
>>>> know
>>>> exactly the way they applied "the resistance" of a way (represented 
>>>> by a
>>>> multilinestring). has someone worked  with pgrouting before? and 
>>>> know if
>>>> i
>>>> can modify their algorithms to adapt them to my requirements?
>>>> thanks
>>> "the resistance" is applied as a "cost" to traverse the segment. All 
>>> cost must be positive. You can use length of the segment as cost for 
>>> shortest distance. or you can compute and assign a cost value based 
>>> on other attributes.
>>>
>>> -Steve
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>>>
>>
> 
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