ArcMap vs ArcGIS Pro Network Analyst results

[ChristinaLindsay]

When I create a Network Dataset in both ArcMap and ArcPro with the same data and same settings (I think), i get slightly different results.  Specifically for Drive Times.  The polygons results for the drive times will be slightly different in Pro than what I got in ArcMap.  It can be different by 700 feet.  There's a possibility the settings I'm setting up aren't exactly the same from the two programs, but if they are are exactly the same, should they produce the same results?  If so, I need to really look into my setting on Pro to find out which settings I'm not matching to ArcMap.

Since the process to create a Network Dataset is a little different from ArcMap and ArcPro, is there something I need to really catch that I'm missing?  It's a slightly vague question, but I'm hoping there might be a simple answer.

[DavidPike]

I think there's been numerous under the hood changes, even to the routing algorithms.  Certainly I remember seeing something about the polygon generation being improved.
I wouldn't be surprised to see differences in the outputs at all but I'd just check for any hierarchy differences, time-of-day/traffic settings etc.

Would be good to get the Esri-take on the differences though. 

[ChristinaLindsay]

I appreciate your take on this.  That does make a lot of sense.  Pro might just have improved results over ArcMap.  

I have asked Esri about this in the past, and I was given a similar answer to yours.  Basically the two programs have different results for reasons that can't really be explained.  Kind of like getting different routing results based on Google and Bing maps.

[RachelApplebaum · Accepted solution]

Hi @ChristinaLindsay ,

(And @DavidPike , too!)

You're both correct in that the algorithms for routing and service area polygon generation are different (and better) in Pro. With service area polygons, keep in mind that the polygons are a secondary output, even if they're what you care about more. A service area travels out from a facility along the network edges/streets until it reaches whatever cost cutoff you've designated. From those streets it generates the polygon. So the polygon is more of an art than a science.

If you want to compare service areas between Pro and ArcMap, generate the service area lines in both and compare those. They should be the same.

Regards,

Rachel

[ChristinaLindsay]

Thank you for that Rachel.  I do remember when I spoke to someone at the UC Conference last year, they offered this explanation as well.  The line feature works best.

Good news is that I did find out the reason for the different outputs.  It had to do with the settings I had in place.  For the Length cost, the value was defaulting to the "Shape" field.  I changed it to the "Miles" field and that helped out a lot.  Pro showed the same results as ArcMap.  I'm happy that it was just that!