create service area based on actual time values in CF output

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05-07-2014 01:01 PM
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New Contributor
I've performed a closest facility(CF) problem, so that I have a time value representing the travel time between a selected set of block group points and their nearest facility.

Now, I'd like to create service areas around each facility point that take into account the actual time value from the field in my CF output of block groups to the same nearest facility.  I'd like my service area break points to be 30 60 90 minutes. 

How would I go about doing this? 

The concept is similar to creating discrete contour surfaces with a set of points based on their values in relation to another point (their nearest facility). I'm interested in skipping Python at this time, if we can.
Thank you.
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Esri Regular Contributor
Could you describe what you're trying to do a little more, or post a sketch of what you're looking for?  I don't understand the relationship you're trying to draw between the Closest Facility analysis and the Service Area analysis.

When you calculated the closest facility travel times, you were presumably using a network dataset with a travel time cost attribute that determines how long it takes to travel on any given street in the network.  The Service Area solver can use the same network dataset and cost attribute.  If you create service areas around your Facilities, the resulting polygons should show the area reachable within your 30, 60, and 90 minute break values.  If the block group points were within those time limits in your closest facility analysis, they should fall under the service area polygons.  However, the service area calculation is completely independent of your closest facility calculation.
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Thanks so much for your reply.
Yes, what you describe below is how I understand the SA function.  I left out some details that would have made it more clear. 

In my CF output, I have the travel time from the road network.  What I also had to do was add on several additional time estimates per types of block groups, so that there's a road network travel time and then a final, total travel time.  It is this final total travel time that I want to obtain a service area of. 

Could you describe what you're trying to do a little more, or post a sketch of what you're looking for?  I don't understand the relationship you're trying to draw between the Closest Facility analysis and the Service Area analysis.

When you calculated the closest facility travel times, you were presumably using a network dataset with a travel time cost attribute that determines how long it takes to travel on any given street in the network.  The Service Area solver can use the same network dataset and cost attribute.  If you create service areas around your Facilities, the resulting polygons should show the area reachable within your 30, 60, and 90 minute break values.  If the block group points were within those time limits in your closest facility analysis, they should fall under the service area polygons.  However, the service area calculation is completely independent of your closest facility calculation.
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Esri Regular Contributor
So each block group has an extra travel time associated with it?  If so, that will be hard to incorporate into a Service Area analysis around the Facilities, since these service areas will have no relationship to the block groups at all.  Can you, instead, generate the service areas around the block groups?  If so, you can use the Attr_[Impedance] field in the Service Area Facilities sublayer to add a customized delay time to each block group.  When you load the block groups as SA Facilities, use field mapping to map your delay time field in block groups to the Attr_[Impedance] field in SA Facilities, where [Impedance] signifies the travel time cost attribute on your network.  Read more about the Attr_[Impedance] property under Facility properties on this page: http://resources.arcgis.com/en/help/main/10.2/index.html#/Service_area_analysis/004700000048000000/

If creating service areas around the block groups isn't what you want, can you explain better how you want to incorporate your calculated extra time from the block groups into the service areas for the facilities?  Do you want to add extra travel time to the roads near each block group?
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