9 replies to this topic

[Esther Mandeno]

Hello,

Not sure where to ask this, so thought I'd try here (also trying at the ESRI forums):

Here's the question:

I would like to perform a small evacuation 'analysis' for a subdivision. The idea is to figure out how long it would take to clear out the subdivision and what road intersections would be potential 'choke' points.

I thought I could do this with Network Analyst (ArcView license level). But I installed a trail version (thank goodness I didn't buy it) and it appears that I can not do the sort of analysis that I want. I can find a route, service area, etc., but not specify 11k+ points (homes) with one car each that would drive to two points at the edge of the road network.

So, what do I need to do the job? Do I need an ArcINFO license and use geometric networks?

Thanks in advance,

[jrat]

It doesn't matter what licence level you have while using network analyst; it still will not do what you want. There are other extensions that might. Try arc Logistics. I don't know if they have a trial version. As far a I know this type of work is normally done with TransCAD. I never thought of using the geometric network. If that works let us know.

[Esther Mandeno]

Thanks for the reply, jrat. I'll check out ArcLogistics. Never heard of TransCAD, but will check that out too. I'll let you all know what ends up working.

[jrat]

I just looked into the ArcLogistics module and I don't think that it will work for your problem. It appears to the same network analyst tools just expanded for fleet management.

[Esther Mandeno]

Hey, that's what I figured too. I've asked around at ESRI and a couple of professors, and it appears that I have to cobble something together between Network Analyst and ArcHydro Tools. I'll try something of the sort today and let ya all know what works (or not).

Thanks again.

[Matthew Hampton]

I just saw a poster at a local GIS conference that achieved a very similar analysis of pedestrian evacuation due to Tsunami warnings in a coastal Oregon town. You might check with Professor Geoffrey Duh at Portland State University. I forgot the student involved with the project - but they used Network Analyst...

[Esther Mandeno]

I'll check him out, too. I have an email query in to Dr. Thomas Cova with the University of Utah - he's done a lot of this sort of stuff as well, but using (I think) different software.

Thanks for the tip!

[Esther Mandeno]

For those who may be interested, I ended up using the Network Analyst Closest Facility function and solved for each and every home to a point of egress. Everything indexed properly before solving. Then stack each solved route for each segment and count the number of times a route was utilitied. Still haven't figured out the intersection overload problem, but will hopefully get that tomorrow. I think it's just a matter of saying so many cars can get through this intersection per minute given the number of lanes, then once that number is reached, that's a potential choke point. Tips on all this garnered from the most excellent Mike Price! Thanks Mike!

[Matthew Hampton]

That's great you were able to solve this. That sounds a lot like how Professor Geoffrey Duh and Lesley Bross solved their Tsunami Evacuation Simulation for Seaside. I happened to snap the attached picture with my phone at the poster session.

 IMG_0894.jpg   687.01K   32 downloads

I'm wondering if the Utility Analyst toolbar might help with your next task. Prof. G.Duh has a website that has some other information regarding evacuation information and data, but I think you're on the right path! <-- very poor network humor

[Esther Mandeno]

Cool! Thank you, sensei Matthew. I'll have to take a look at that next week.