I have a shapefile that has an ID field(type=double, precision=15, scale=0). I am trying to add a new field(ID_2) that has the same field attributes as ID(Double,15,0). However, when I add the ID_2 field it seems like the new ID_2 field is being rounded to a precision=12.enter image description here

I've tried adding the new field both manually within ArcMap Desktop 10.5 and also using the Add Field tool in a Python script; both methods result in the ID_2 field being rounded and the last 3 digits replaced with zero's. I also imported the same streets shapefile into a file geodatabase, added the ID_2 field, and calculated from the ID field, and that worked exactly as I would expect.

Also strange is if I right-click on the new ID_2 field and go to Properties, it shows the Precision=0.enter image description here

Does anyone have any idea why my Double field isn't being added with a precision of 15, and is instead seemingly being rounded, chopping off the last 3 digits of the ID?

  • 2
    How did you calculate ID_2 to be the "same" as ID? – PolyGeo Feb 1 '17 at 23:01
  • 1
    There's more than one numeric type in a dBase file. ArcGIS only uses one of them for write, and I don't think that format supports a 15 width. Floating-point values make unreliable identifiers for this reason. – Vince Feb 2 '17 at 1:56
  • With numbers that large I'd convert to text, for one of the reasons mentioned by @Vince above, create a text field for ID_2 and use field calculator to cast the numerals to string str([ !ID! ]) with Python. These are unique IDs that do not need to be numeric as the values will not be used in any analysis. Thay are simply an identifier. – Clubdebambos Feb 2 '17 at 7:44
  • @PolyGeo I right-clicked on the ID_2 field header and used Field Calculator (ID_2 = !ID!). – mtbnski Feb 2 '17 at 14:03
  • I am using TomTom shapefile street data which comes with the ID field as (Double, 15,0) which is displayed properly as shown in my screenshot above, so ArcMap can display a double field with 15 digits. I tried the exact same steps (adding ID_2 field and populating from ID) with the same data on a different computer running ArcMap 10.3 and ID_2 was calculated correctly with 15 digits. Either there is a bug in 10.5 or my ArcMap needs to be reinstalled. – mtbnski Feb 2 '17 at 14:14

This is a known ESRI bug, which has existed since 10.4. The original bug (BUG-000095512) was determined to be "by design" and was closed. It still exists in 10.5 and enough people have complained that ESRI has reopened the case under BUG-000099718. The links may require you to have an ESRI account, so here is a screenshot of BUG-000099718. enter image description here

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