Network Analyst: Ever computed a *DO* Cost Matrix?

[YannKACENELEN]

Hello everyone,

I need to compute the 20 nearest fire stations - out of 51 - from each of the 70,000+ streetlines' midpoints of our county road network.

Since 2007, good ol' Network Analyst for ArcView 3.2 has annually processed such a big amount of calculations thanks to an adhoc Avenue script using 'FindClosestFacilities' function. This script runs like a charm for approx 24 hours to get all done - including reformatting output results into customized tables.

Time has come to switch to up-to-date tools and languages (Python) for hopefully a more efficient processing chain, at least less time-consuming and better integrated with our ArGIS environment.

I gave some tries with ArcGIS' Closest Facility solver, but the OD Cost Matrix is definitely the tool I need, as it is much much faster than the latter and I don't need to output the precise routes feature layer but the tabular data.

The problem is that the matrix I expect requires the 20 fire stations to be set up as the destinations and the 70,000+ centroids as the origins, so that destination ranks range from 1 to 20. But fire engines start from fire stations, right?

The big question is: is it possible, by way of a Python script, to compute not a Origin-Destination Cost Matrix but a Destination-Origin Cost Matrix? with (hidden?) settings like Closest Facility solver's 'TRAVEL_TO' and 'TRAVEL_FROM'?? If not, will the use of ArcGIS' Closest Facility be as reliable and faster than its odl AV3 predecessor?..

Thanks a lot in advance for your help, answers or hints.

Best regards,

- Yann

[MelindaMorang · Accepted solution]

Hi Yann.  Actually, you should be able to solve your problem with Closest Facility.  You can just turn the output shape generation off (the No Lines option), and this will eliminate the time and memory overhead of storing the route geometries, which you don't need.  You can use the other settings to control the direction of travel and the number of facilities to find.

If you try this and don't find our latest Closest Facility solver to be "as reliable and faster than its odl AV3 predecessor", please let us know.

[YannKACENELEN]

Hi Melinda,

Thank you so much for your quick and efficient reply!

Been working on that since last Monday and it works like a charm. The Network Analyst's Find Closest Facility solver proves to be pretty fast indeed with this 'NO_LINES' parameter.

So I've dug into ArcPy to migrate my old Avenue scripts. It should be up and running in no time, thanks to your help.

Farewell AV3. These past 15 years have been great working with such a reliable tool, enriched by a not less great community of users. It's ArcGIS time, now, still with this uncomparable community.

Have a great day Melinda, and all the folks here on GeoNet.

- Yann