I am performing shortest path analysis on a public transport system in which I have many bus routes. Obviously some transfers are necessary to gain access to every part of the city. The junctions in my network are where routes cross each other. Does anyone know of a way to limit the amount of turns (in reality; bus transfers) that the route takes to, say, 2 transfers? When I run the closest facility function in network analyst I get paths that have many bus transfers, sometimes back to a bus it was on previously! I realise that this is in fact the shortest path and by limiting the amount of transfers it is lengthening the path but it just isn't realistic. Maybe there is a tool other than the closest facility function that I am overlooking that is better suited to the task? Something that allows constraints?
There are also some routes that don't overlap and involve a short walk to make the transfer. I have a layer with the road network too so is there a way of linking the two but making the bus routes a higher priority?
I think i have read anything one day about that.....
Another way is considering that in every bus stop have some delay,
Another is, considering time in route, example, the route that result is the route that takes less time to take, because every time you go down bus, and up to the other you should wait some time. every stop has a waiting time.
If the problem is only length , then i don't know. Network analist count barriers , i don't know how, maybbe a function or vba script, have seen many doc's about that but without source code
Does anyone know of a way to limit the amount of turns (in reality; bus transfers) that the route takes to, say, 2 transfers?
There is currently no way to directly enforce any hard constraints on the number of turns or "transfers" taken by a path in the Network Analyst solvers. However, as mentioned in the previous response, you can penalize such "transfers" to limit the possibility that they might be taken.
For example, you can create turns for all transitions from a road line to any adjacent bus lines (connected via a bus stop), and vice-versa. These turns would represent the "transfer" of getting on or off a bus, respectively, at a bus stop. You could then penalize these turns as you see fit, to represent an appropriate delay.