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04-26-2010 09:05 AM
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New Contributor III
If I want to create a service area around a hospital based on travel time, what data would I need?  Where can I get speed limits for roads (if I need that data) for Pennsylvania?  I'm using 9.3.1.  Is the Census Bureau's TIGER files for Pennsylvania counties useful for the analysis?  Thanks.

Jim
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Esri Regular Contributor
Jim,
You can use the free nationwide streetmap data that comes on the Data and Maps DVD with ArcGIS.
It has then network dataset already built with travel time attributes. It will be better than the TIGER
data that you can get. Regards,
Jay Sandhu
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New Contributor III
Jim,
You can use the free nationwide streetmap data that comes on the Data and Maps DVD with ArcGIS.
It has then network dataset already built with travel time attributes. It will be better than the TIGER
data that you can get. Regards,
Jay Sandhu


Thanks, Jay.  Much appreciated.

J
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New Contributor
Hi.  I am also new at ArcGIS and have been struggling to figure out a similar problem.  I have ArcInfo with the Network Analyst extension and I am trying to create service areas around hospitals in order to evaluate drive time.  I also have North American StreetMap.  I am able to cut the data to the areas I want to study.  When I try to create a network database it asks for attributes, but I am not able to find miles (a distance attribute) or minutes ( a time attribute).  When I look in the streetmap_na folder and at the data elements in the StreetMap North America.mxd file, I do not see a distance date element or a time data element.  So overall, the main question is how do I create a network database for developing service areas from the files included in StreetMap of North America?  Thanks.
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Esri Regular Contributor
Why can you not use the streetmap network directly with Network Analyst to create the service areas? There is no need to "cut" the data into smaller areas and then try to create network datasets on it. Simply add the streetmap network to ArcMap, create a service area layer, bring up it's properties and on the Analysis tab switch to Length in miles instead of the time in minutes, add your location and solve.

If you have extracted the data and want to add a length field, then you can use the field calculator. See more on this at:
http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?TopicName=Making_field_calculations

Jay Sandhu
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Thanks for your advice  and again please excuse if I am a newbie on all this.  When I have tried creating a network data set, the suffix is "NDS".  However, in looking through all the files from StreetMap, I do not see any files with this suffix.  Additionally, when I open up the file: "StreetMap North America.mxd", I do not get any choices (except Options) when I look at the Network Analyst drop down menu. Please advise how to proceed.

Thanks,

Jon Mark
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Esri Regular Contributor
You can open the streetmap mxd and then click on the + or ADD button. Browse to where the streetmap data is stored, scroll to the bottom and you will see a Streets network. Add that to ArcMap. Now the network analyst toolbar will be active. If you go into the streetmap folder with explorer, you will see a Streets.RS file that contains the definations of the network dataset based on SDC data and the streets.rsx folder contains the binary files for the network. So there is no "NDS" file for SDC data. Hope this will be enough to get you started.
Regards,
Jay Sandhu
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New Contributor
Bingo!!  Thanks.
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