[Gdal-dev] problems with average

[Thekla Wirkus]

Hi,

the problem is undissolved. With
gdaladdo -r nearest bild_8bit.tif 2 4 8 16
the result-TIF has mistakes at page 2-5 too.

Best regards
Thekla Wirkus



Frank Warmerdam schrieb:
> Thekla Wirkus wrote:
>> Hi,
>>
>> I have problems with creating a multipage-TIF with:
>> gdaladdo -r average bild_8bit.tif 2 4 8 16
>> the result-TIF has mistakes at page 2-5, page 1 is OK. The hatches are 
>> normally single colors but after using gdaladdo -r average ...
>> they are shown with multicolors and they are blurred.
>>
>> See the result at:
>> http://wms1.ccgis.de/mapbender_dev/tmp/ergebnis_bild_8bit.tif
> 
> Thekla,
> 
> Average downsampling is inappropriate for discontinuous images.  That
> is images where nearby pixel values are not necessarily nearby colors.
> Your image has a colormap (and not just a continuous color ramp) and so
> fall into this category.
> 
> You should use the default nearest neighbour downsampling instead of
> using "-r average".
> 
> Best regards,


-- 
Mit freundlichen Grüßen
Thekla Wirkus




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