topic Breaking up data by county in Geoprocessing Questions

Breaking up data by county

__ — Thu, 08 Apr 2010 18:21:34 GMT

I am trying to figure out a simple automated way (by script or model building or whatever works) to break up polygons into counties. The end goal is to have all of my data (including precipitation and seismic hazard and other parameters that do not respect political boundaries---see attached image) in county format so that I can use modeling methods such as GWR on a single county shapefile with all parameters.

My issue is that I don't know how to turn variables like seismic hazard into a representative county coverage. I think I should be able to use a script to clip the seismic hazard individually for each of the 96 counties. Then I would have only a few polygons of seismic hazard inside an individual county. Next I could take compute an area weighted average of those polygons to get the value for the individual county.

I can do this process by hand for one parameter at a time and one county at a time, but that won't work for 96 counties and multiple parameters.

Thanks.

Breaking up data by county

JeffLee — Thu, 08 Apr 2010 22:01:24 GMT

What you could do is convert your surface into a raster and calculate zonal stats for all your polygons in one operation using spatial analyst.

Breaking up data by county

__ — Thu, 08 Apr 2010 22:28:04 GMT

That sounds promising. I know that I can use the Polygon to Raster conversion tool, but I'm lost about how to do the rest.

Breaking up data by county

__ — Thu, 08 Apr 2010 22:30:43 GMT

Sorry. It makes sense now. I didn't see the tool at first.

Breaking up data by county

JeffLee — Thu, 08 Apr 2010 23:43:46 GMT

Here is a screen cap of the tool location in the toolbox. you can either use the zonal statistics or zonal statistics as table to generate your summaries per counties

Breaking up data by county

ShitijMehta — Fri, 09 Apr 2010 16:13:21 GMT

If you are using 9.3 or 9.3.1 try any of the two approaches within ModelBuilder:
1)
Create a series feature class variable in ModelBuilder and insert all the values from your county table. See how series works:
http://webhelp.esri.com/arcgisdesktop/9.3/index.cfm?TopicName=Iteration_using_Series
and
http://resources.esri.com/geoprocessing/index.cfm?fa=codeGalleryDetails&scriptID=15728
Please read help for the model on how series variable is used.

Or

2)
There is a model with a script tool which reads through each of the record value for a field and makes a selection for that particular feature. So if use this script tool you will select each county based on FID (for example). You can then use copy feature tool to copy that selected county as a separate feature class or simple used that selection to clip another feature class. Pls read help for the tool.
http://resources.esri.com/geoprocessing/index.cfm?fa=codeGalleryDetails&scriptID=15710