[postgis-users] Looking for single-destination (shortest path) program

[Stephen Woodbridge]

Fay,

A way you could solve this is to compute the path FROM the client 
instead of TO the client. If you do this then you will have the time to 
get to the client from all the cars in a single solution. and it is an 
easy matter to find the closest car.

-Steve W.


Fay Du wrote:
> Hi everyone:
> 
>  
> 
>    I am trying to use pgDijkstra in my project. pgDijkstra calls boost 
> library which provides single-source shortest function. My network is a 
> street network. The graph is directed. My typical scenario is, there is 
> one client calls dispatch center and there are many cars (for example, 
> 100 cars) are available all over the network. I want to find the closet 
> car and dispatch it to the client. It is a single-destination problem. 
> Does anyone know if there is an existing single-destination program 
> exists available for my project? Or the explanation of the 
> single-destination algorithm?
> 
>    I know I can call pgDijkstra multiple times to get the answer. The 
> performance of the solution is not good. Our goal is to calculate 
> shortest paths of 100 cars to the same destination in less than a 
> second. Calling pgDijkstra 100 times takes much, much more time than our 
> goal.
> 
>  
> 
> Many, many thanks.
> 
> Fay
> 
> 
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