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One way to do this would be to replace all values between 4 and 7 by
NULL (e.g., r.null map=yourRaster setnull=4-7). Then use r.neighbors
to calculate the mean of the nearest neighbors (e.g., r.neighbors
input=yourRaster output=intermediateResult size=3. Have a look at
the help file of r.neighbors and the part about the size of the
neighborhood and option to use a circular neighborhood). Last step,
patch the two layers together (e.g, r.patch
input=yourRaster,intermediateResult output=yourOutput).<br>
<br>
As for your second question, r.stats is indeed what you are looking
for I think, it calculates the surface for each categories of the
input raster layer. <br>
<br>
Rgds<br>
<br>
Paulo<br>
<br>
<br>
<div class="moz-cite-prefix">On 05/04/2013 08:17 PM, BLANDENIER
Lucien wrote:<br>
</div>
<blockquote
cite="mid:84F1DDBD03D55944AA4E63A2FE5EADE53BF282B6@MAIL-MBX-05.UNINE.CH"
type="cite">
<pre wrap="">Dear Grass users,
I'm working with rasters maps of large area and I want to calculate surface related to specific colours. Before this, I have to replace the surfaces of the rivers by the surrounding value (or the mean of the surrounding value).
I looked at the manual of r.mapcalc but I didn't found how to do this...
For instance, I want to replace all value between 4 and 7 by the mean of the value of the 4 nearest pixels.
Is there any way of doing this?
Which command shall I use then for calculating the surface for each color? r.stats? or is there a command that directly computes the surface?
Best regards
Lucien
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