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Is it possible, to correct a raster DEM by changeing the raster-cell-values manually, like by "painting"?
My DEM (ASTER) have one small error where the elevation is about 300m below the actual elevation. It should be a hill, and not a hole...
SRTM 4.1 is good, but has other errors (the hill is very steep and small, so SRTM "ignores" it (<90m).
Yes, in GRASS you can edit raster cells graphically with d.rast.edit.
I hesitate to mention this because markusN's answer is so good. But if you don't get on with GRASS and if your DEM is not too large you could try the following.
Firstly, note the coordinates for the pixels that you wish to edit. Then explode the DEM to xyz triplets using gdal2xyz:
gdal2xyz.py input_dem.tif output.csv
'output.csv' will be a space delimited text file containing the xyz triplets.
Next, load 'output.csv' into a plain text editor, search to find the coordinates and change their z-values as required. Save the file, then convert it to a DEM TIF using gdal_translate:
gdal_translate output.csv new_dem.tif
Nick.
There is another Qgis plugin designed for that: ThRasE
Disclosure: I developed this plugin, and I don't want to promote it, I just want to share another option
Although this is an old question, I stumbled upon it in search for the same thing. I later found that the Serval QGIS plugin does exactly what you asked.
You can also use the Raster calculator to change certain values on the raster. For example, if you want to transform all values between 300 and 310 to 305, raster calculator can do that. The QGIS manual has some examples on this. The last 5 minutes of this YT video also has an example on this.
