Service Area analysis streets layer options?

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01-12-2012 04:56 AM
MarthaSnyderwine
New Contributor
Hi!  Could use some advice here.  This is my first cut at Network Analysis (NA).  I need streets for VA, MD, DC, DE, WV, and PA states to generate service areas in increments of 30minutes.  I've been able to generate the service areas when I use the TIGER roads shapefiles for just the primary and secondary roads.  Not surprisingly I get a very coarse result, but at least it works.  I've done this for the VA, MD, and DC layers with my locations. 

To improve the accuracy and realism, I've downloaded the North America Detailed Streets available here:  http://www.arcgis.com/home/item.html?id=f38b87cc295541fb88513d1ed7cec9fd.  This layer has 40million plus records.  I exported out the states of interest and still have a pretty large set of 1.5million.  Every time I try to create a network dataset it runs for over 30 minutes and then I end up forcing it closed.  I did succeed by creating an even smaller subset of roads, less than 500,000 but this network dataset is to small, since I need to create service areas by 30minute increments. 

What am I doing wrong here?  I've tried looking at the lengths of the North America Detailed Streets and they are remarkably short, hundredths of meters.  Should I re-install this data? 

Is it possible to get a trial of StreetMap and experiment with that? Or is this the same as the layer I'm working with?  Will I still have the "slow" problems since I expect this is a very large set of records as well.  I've looked into the Open Street Map (OSM) data and that's quite a firehose of data as well at the state level. 

I am an ArcMap 10.0 user with SP3.

Thanks, Marti
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JaySandhu
Esri Regular Contributor
Building a large network dataset can take some time. You can go to the %TEMP% folder and see the contents of the BUILD.TXT file to see what progress is being made by the build.

A version of the streetmap is available free with ArcGIS. It is on the data and maps dvd. It already has the network dataset built for it. There is no need to extract the streets and create a network on the subset. It is also available online. Perhaps you have already downloaded it. You can search the forums for other posts on people setting it up, for example:
http://forums.arcgis.com/threads/15722-ESRI-StreetMap-network-dataset-error?highlight=streetmap+down...

As far as the lengths being small, the streetmap data is in decimal degrees and that is why you see small lengths. If you use the network dataset wizard to create the network, do not add any attribute and when you go "next" it should say that it will add a length attribute based on the correct length in meters.

Jay Sandhu
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MarthaSnyderwine
New Contributor
Jay,
Hello! Thanks for your response. I had not yet downloaded the Data & Maps from my companies distro site when I posted since that's about an hour plus process. I was thrilled to find the Streetmap data and Network.

Thanks again,
Martha
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