topic Re: OD Cost Matrix for symmetric distances in ArcGIS Network Analyst Questions

OD Cost Matrix for symmetric distances

TheophileEmmanouilidis — Tue, 01 May 2012 16:03:00 GMT

Hello all,

For research purposes, I am currently solving OD Cost Matrix to compute shortest paths distances for about 10'000 origins and destinations (origins = destinations). I am using a undirected network, so the distance from A to B equal distance from B to A (symmetric distances). Therefore, do anyone has an idea on how to customize the OD Cost Matrix tool so that it only computes A to B and not B to A ? This would halve the size of the database and the computing time.

Any idea ?
Best regards,
Theo

Re: OD Cost Matrix for symmetric distances

TheophileEmmanouilidis — Tue, 01 May 2012 16:14:29 GMT

Sorry, this question has already been asked:
http://forums.arcgis.com/threads/55350-Economizing-OD-Cost-Matrix-when-A-gt-B-B-gt-A

Theo

Hello all,

For research purposes, I am currently solving OD Cost Matrix to compute shortest paths distances for about 10'000 origins and destinations (origins = destinations). I am using a undirected network, so the distance from A to B equal distance from B to A (symmetric distances). Therefore, do anyone has an idea on how to customize the OD Cost Matrix tool so that it only computes A to B and not B to A ? This would halve the size of the database and the computing time.

Any idea ?
Best regards,
Theo

Re: OD Cost Matrix for symmetric distances

RamB — Thu, 03 May 2012 16:34:53 GMT

Hallo,

I am assuming that your O and D are same in number and same in locations. I am also assuming that OD cost matrix can be called with a python script. If above two conditions are true, then a small code "if j > i then calculate distance" will give the required result, where Ai is set of O and Bj is set of D and i is exact same quantity as j, because number of O = number of D. This will give you matrix values above the diagonal, that is one half of the matrix (diagonal being zero of course)

Regards

Hello all,

For research purposes, I am currently solving OD Cost Matrix to compute shortest paths distances for about 10'000 origins and destinations (origins = destinations). I am using a undirected network, so the distance from A to B equal distance from B to A (symmetric distances). Therefore, do anyone has an idea on how to customize the OD Cost Matrix tool so that it only computes A to B and not B to A ? This would halve the size of the database and the computing time.

Any idea ?
Best regards,
Theo