Closest Facility Solver

129
4
10-14-2010 07:39 AM
Highlighted
New Contributor
I have 172,000 addresses for which I am finding 4 closest facilties (EMS Stations) by rank. If I add an ADD_PT_ID inside my address table, and add a field inside incidents, I am unable to load locations as incidents. I am field mapping Lable_Name to Name; and the newly added field to ADD_PT_ID. It loads to 100% when I am looking at the status, but gives out 0 in the end. Can I not import the ADD_PT_ID into the incidents?
My network featureclasses are inside mxd; and I have ArcInfo. Any help would be helpful!

Thanks!

S B
Tags (2)
Reply
0 Kudos
4 Replies
Highlighted
Esri Regular Contributor
Shilpa,

Not sure what is going on...let me understand the workflow, you create a CF layer, add a field to the Incidents called ADD_PT_ID and then do a load locations and map ADD_PT_ID and load fails?
Does the type of the ADD_PT_ID field agree with the contents of the ADD_PT_ID field on your data?

If you plan to re-use these addresses, perhaps you can run the GP tool call Add Locations to add the location fields once and then when you do the Load Locations, choose the "Use Network Location Fields" to make it load much faster. This will make it possible to "debug" what is going on you will not have to wait for so long each time you load the points while trying to make this process of mapping the ADD_PT_ID field work.

And I will suggest couple of other things since you are loading a large number of locations:
If you only want the shortest path distances and not the actual route geometry to the four closest, then use the OD Cost Matrix solver as it will go quicker. Here the CF facilities would mean destinations and the CF Incidents would be Origins.
Also, if the four closest locations are reasonably close, say 30 minutes, then turn off hierarchy AND put a cutoff of 45 minutes and solve. It will solve much faster as hierarchy works great for long distances and has a larger overhead for short distances (I am assuming you have a hierarchy built into your network dataset).

Regards,
Jay Sandhu
Reply
0 Kudos
Highlighted
New Contributor
Thank you so much for all the leads Jay. for some reason, ArcMap did not like my Field name (ADD_PT_ID_I) inside incidents. After I renamed it (to match ADD_PT_ID), it worked fine. And yes, I need actual time computations using my speed limit field, so I have been using closest facility; just not drawing actual routes on map.
But now my arcMap crashes after solving about 75% when I specify 4 facilities to find by rank. It must be because I have 172000 addresses to begin with. When I solve for 1, it gives me a good result. Anything more than 1, and the map crashes. Any ideas?

Thanks,
Shilpa
Reply
0 Kudos
Highlighted
Esri Regular Contributor
Shilpa,

It is likely that computing and storing the 172,000 by 4 route shapes and updating them in ArcMap is running out of memory. You can imagine that it is trying to populate an in-memory feature class with 688,000 lines. You can try "chunking" as described here:
http://resources.arcgis.com/content/kbase?fa=articleShow&d=30759

However, it looks all you need is the travel time and not the actual route shape geometry returned back, so I will again suggest that you use the OD Cost matrix solver. Make sure to set destinations to 4 and set a cut off (say 30 minutes) and turn off hierarchy and re-solve.

Jay Sandhu
Reply
0 Kudos
Highlighted
New Contributor
Thank you Jay! I was able to solve it using OD cost metrix. I was stuck on closest facility because I thought I may have to draw routes. But OD went so much faster. Thanks again.
Reply
0 Kudos