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I am working on a road network and each section is assigned a certain value and increases by 1 each section until it gets to around 500 which is the end.

A change I had to make was adding two sections to the beginning of the road which now means every value on this segment is two below what it should be with the addition of these two sections.

I know there's a way to do this in field calculator, but it is definitely my weakest area of expertise in ArcMap.

What kind of function should I use to make these changes?

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    Can you not create a temporary field, then select all the sections that are incorrect using the select by attribute where "section >2" then in the field calculator [section] + 2 and then in the section field simply make it equal the temp field? without seeing the data, I cant get the field names / syntax exact, but that is what I would try first. Delete the temp field when done and then clear the selection.
    – Keagan Allan
    Commented Oct 22, 2019 at 22:53
  • If your data is in a database which you don't want to change the structure of you can export a dbf of the selected roads (the ones that need to change) with summary statistics, statistic field OID type count and case fields of OID and your field in question, from here add a new field to the dbf, calc as @KeaganAllan suggests then join by attributes (keep only matching) the exported table OID to OID_1 and calculate the field over the join, remove the join and it's all done. Note: to calculate over a join ArcMap will want you to be editing.
    – Michael Stimson
    Commented Oct 22, 2019 at 23:27

1 Answer 1

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If your values are all in a field called SECTION and you want all these values to be increased by 2:

  1. Start an Edit Session (means you can Undo after running Field Calculator if it doesn't do what you want)
  2. Select the features you want to update
  3. In the attribute table, right-click on the field you want to update and open the Field Calculator

  4. Enter the following expression:

    [SECTION] + 2

  5. Run the calculation, and check the results. If they are good then Save/Stop editing. If they're not good then Stop editing without saving.

This should increase the values in your field by 2.

enter image description here

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  • Thanks this is exactly what I was looking for! I figured it would be easy but I didn't know it would be that easy.
    – richie
    Commented Oct 23, 2019 at 13:17
  • @richie If this has answered your question please consider up-voting and marking as the Answer. See What should I do when someone answers my question?
    – Midavalo ♦
    Commented Oct 24, 2019 at 2:56

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