[OSRM-talk] Questions on OSRM normalized file format

[Stephen Woodbridge]

Hi all,

I'm currently the lead developer for pgRouting and I'm interested in 
being able to create a local instance of OSRM that can be accessed via 
pgRouting. This all seems pretty straight forward to prototype up.

At the moment, I have a few questions on OSRM normalized file format. I 
want to be able to write a utility program for postgresql to prep and 
dump a pgRouting topology to an OSRM normalized file.

Looking at the edge section:

It appears that edges can be entered as undirected (ie: twoway with same 
costs in both directions) or directed in the case of oneway streets.

1. if I have a edge with different to-from and from-to costs am I 
correct in assuming that the way to enter this is to split the edge and 
enter it as two oneway edges with the appropriate costs?

2. oneway edges must be entered where from->to is the direction of the 
edge, ie: the direction must be to the target node?

3. Can you expound on the "rank of the speed profile"? Is this still 
used? in the Speedprofile page it says that this is now handled as LUA 
scripts.

Looking at the turn restrictions section:

Is there a graphic that explains this better. It is a little bit hard to 
follow where the various items come into play. There are references to 
via-node, from-node, to-node, from-way, and to-way.

Here is a common use case that I need to model. It is a majow road 
digitized as separated north and south bound lanes and intersected by a 
two way street digitized as a single line.

           e     h
           |     |
           |     |
           |     |
a---------b-----c---------d
           |     |
           |     |
           |     |
           f     g

Traffic is allowed:
ab-bc-cd   - east bound cross traffic
dc-cb-ba   - west bound cross traffic
eb-bf      - one way south bound traffic
gc-ch      - one way north bound traffic
ab-bc-ch   - east bound onto north bound
ab-bf      - east bound onto south bound
dc-ch      - west bound onto north bound
dc-cb-bf   - west bound onto south bound
eb-ba      - south bound onto west bound
gc-cd      - north bound onto east bound

U-Turns are not allowed:
eb-bc-ch   - south bound u-turn to north bound
gc-cb-bf   - north bound u-turn to south bound

and more obviously any turn the wrong way down a oneway edge.

Any help in understanding this would be greatly appreciated.

Thanks,
   -Steve