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I have a polygon shapefile (with 4000 records in it) that I want to group into different regions by doing a "select by attribute". I need to do this about 164 times because of the different selection ranges I use in the expression (eg nr >= 1000 AND nr <= 1119).

For each new selection I need to calculate the Fieldname(Region) to the name of the new region (again 164 times)

How can I achieve this in ModelBuilder?

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  • btw Im totally new ni using modelbuilder and programming
    – user6014
    Commented Feb 20, 2012 at 9:20
  • So you have 164 unique expressions to calculate against?
    – artwork21
    Commented Feb 20, 2012 at 15:04
  • the 4000 records range from 1000 to 4026. I have to select values >=1000 and <=1119 and if this is true, then all these records goes into Region 1. Same calculation for Region 2 but values >=1120 and <=1159. and so on for region3 up to region 164. I also want to make sure that the Region field gets calculated at teh same time eg. if value >=1000 and <=1119, the "calculate field('Region')= 'Region1'. etc etc
    – user6014
    Commented Feb 20, 2012 at 15:40

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You state you already know that you have 164 expressions to run, which would give you 164 regions, but each expression varies slightly. So you must have knowledge or a list of the ranges each region will be?

You could use Excel to create a column where each row contains the sql expression you intend to run in the select by attribute tool and save this off as a dbase file where the region number is implied by the row number.

If you are using ArcGIS 10 then you could use a for iterator to step through your dbase and using the field (which would be a string field) to be the expression for the select by attribute and the value to be the region number to assign to the selected fields

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    If you're going to use Excel, you might just as well reclassify the [nr] field right then and there! You can do it by setting up a sorted array of breakpoints and indexing into it using VLOOKUP (with the range option set to TRUE).
    – whuber
    Commented Feb 20, 2012 at 19:01
  • Thank you for the advise. Also thought to rather do it in Excel.
    – user6014
    Commented Feb 20, 2012 at 22:28

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