3 Replies Latest reply on Apr 19, 2012 4:59 AM by jamesh

    keep null values with data exclusion


      I'm classifying point symbols based on a numeric field [result]. I want to exclude and display differently any data that has a "U" in a separate field [qualifier], this can be done with the 'data exclusion' feature, but all null values will be discarded. A null [qualifier] means the [result] is valid, and shall be displayed based on the quantity classification. Is there a way to include null values without editing the field or copying the layer & reclassifying? It makes no sense to me why null values must be eliminated.


        • Re: keep null values with data exclusion
          I confirm this strange behavior in AG10 sp4.
          Moreover, this same happens when Definition Query is set (eg. "A_strings" <> '1A' ) - besides the excluded value, all records with NULLs are excluded.

          In your case, when you want to preserve NULLs, you can try:
          "qualifier" IS NOT NULL
          • Re: keep null values with data exclusion
            Thanks m.gasior :-)

            That works with a definition query, but not with quantity symbol classification using exclusions. For now, I populated all <null> values in [qualifier] with a "-" but in a table that looks like it means something. <null> indicates that the [result] is valid, so if there's anything in the [qualifier] field, that is a flag that alerts the user to a potential problem with the result.

            Is there an environment setting to handle null values this way? If not, can ESRI make this available soon? There are many other instances where this has been a problem for me.
            • Re: keep null values with data exclusion
              ... a thought: I could change the "-" to a " " (space) so it looks blank to the user & not get tossed out as <null>...