[postgis-users] Optimal path with alternative paths

[Anton Patrushev]

Hello,

> Now I need to get the optimal path and three other best possible alternative
> paths (next three best options) between the same origin to the destination.

This problem is called k-shortest path problem.

> What is the way to do it?

Not with pgRouting in its current state. But there is demand on such
thing and there are few solutions already exist.
For example, please refer to http://pgrouting.postlbs.org/ticket/178 -
there you'll find a link to open source k-shortest path solver. If you
like to play around with C/C++ you can make it work with pgRouting and
hopefully contribute it back to the community :)

Anton.