Possible Duplicate:
Raster generalization - buffers in rasters, expand pixels?

I have a 1m LIDAR DEM which I'm manipulating in QGIS.

I'd like to smooth the DEM, such as by having each pixel become the average of its 3x3 neighbourhood (a low-pass filter?).

Is there a way to do this in QGIS?

marked as duplicate by whuber Aug 7 '12 at 22:20

This question has been asked before and already has an answer. If those answers do not fully address your question, please ask a new question.

  • You will find your answer by searching this site. Including "neighborhood" as a keyword turns up a direct answer to a near-duplicate question. – whuber Aug 7 '12 at 22:20
  • The question you indicated as being a duplicate of mine is certainly not a duplicate. The answer is helpful, but I doubt someone with my question would find it. – Richard Aug 8 '12 at 1:39
  • Richard, could you please explain how your question is different? Note that the solutions r.mfilter and r.neighbors directly solve your question as asked. I found this answer (among many others) through the search linked in my comment and offered it as one of many possible duplicates because it provides a broad range of solutions to your question. – whuber Aug 8 '12 at 13:04
  • But, @whuber, you've predisposed yourself to rejecting that explanation. The answers may lead to the same place, but the questions themselves are dissimilar. I would never have thought that "Raster generalization - buffers in rasters, expand pixels" was asking the same question as "QGIS Smooth Raster DEM". I'm glad you think the two mean the same thing; I don't. I asked my question after searching and, in searching, learned a lot about smoothing, but nothing I found addressed smoothing within QGIS - which is what I wanted to do. – Richard Aug 8 '12 at 15:45
  • Richard, I wasn't suggesting that you should have found an answer directly by searching. However, on this site a "duplicate" does not have to be exactly the same question: it suffices that it cover the same ground and have substantially the same answer. By closing one version and providing links to the other, we thereby create a better resource for future users and enhance the meaningfulness of our threads by means of these semantic connections. If you still have any remaining questions, then by all means ask them! But at least you will have made progress in the meantime. – whuber Aug 8 '12 at 17:49

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