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Question

Topologybuilder attribute merge not working as it used to

  • March 27, 2026
  • 1 reply
  • 65 views
aron
Enthusiast
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I have been using Topologybuilder to merge attributes from overlying features. This worked fine as long as empty cells where set to NULL. Now for some unknown reason this does not work any longer. 

Example of two overlying features:

Feature 1: attributeA = NULL

Feature 2: attributeA = 'valuesomething'

The output used to be one feature with the value 'valuesomething', but now I get the value NULL in stead. Has the way the Topologybuilder works been changed? Does anyone have a workaround?

      1 reply

      crystalatsafe
      Safer
      Forum|alt.badge.img+30

      Hi ​@aron 

      This may be happening because of the order those attributes are processed.

      You could try using a NullAttributeMapper upstream, or using a Sorter may also work well.

      Here are some articles you may find helpful:

      How Does FME Handle Null Attribute Values?

      Sorting Tabular or Graphical Data

      Attribute Processing Example Workspace (CSV to MapInfo)

       

      I have submitted an internal ticket to our development team (FMEENGINE-97722) and I will make sure to keep you updated on the progress.

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