I am in the final stages of a landcover classification and need to reclassify thematic raster values that are inside different polygon masks, while leaving the values outside as they are.

Can I do this with raster calculator? And, if so, how?

  • Apologies. I meant to add that I need to do this is in ArcGIS.
    – Simon
    Commented Aug 21, 2013 at 13:45
  • 1
    check this question: gis.stackexchange.com/questions/40474/…
    – Gago-Silva
    Commented Aug 21, 2013 at 14:08
  • Thanks, but I need to reclassify specific classes inside the polygon mask, rather than make all the cells inside the mask one value.
    – Simon
    Commented Aug 21, 2013 at 14:36
  • I'm voting to keep it open, as I feel it is sufficiently different from the candidate question. Commented Aug 21, 2013 at 15:22
  • Reclassify the entire raster, then replace the original values by the reclassified values using Con. For details, search our site for applications of Con.
    – whuber
    Commented Sep 27, 2013 at 15:48

1 Answer 1


Because the Raster Calculator is a spatial analyst tool, you can utilize the Mask environment.

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From there, you can use a variety of commands to perform the reclassification: common ones include Con, Pick, Is Null and Set Null, based on your needs.

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To check if a specific spatial analyst tool honors the Mask environment, simply scroll down to the bottom of the help page and check the available environment settings.

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  • 3
    Love the first illustration. It very clearly explains what is changed, however the answer itself doesn't address "leaving the outside values as they are", exactly. It leaves the outside values behind. Commented Dec 7, 2017 at 18:20

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