[gdal-dev] gdalwarp vs gdal_translate for resizing images

Rutger kassies at gmail.com
Fri Oct 28 01:37:27 PDT 2016

While on the subject, i'm not aware of the implementation details of GDAL's
bilinear algorithm**. But normally you go from four source points/pixels to
a new one. How is this handled in extreme downsampling cases like Travis is
doing? Decreasing resolution a factor of 20, you're going from 400 input
pixels, to 1 output. If you would take four pixel into account you are
ignoring 99% of the input signal. From an algorithm perspective that could
be correct, but this is not always intuitive as a user. 

So Travis, have you considered using 'average' instead of bilinear? 

**I checked for 'nearest neighbor', and (of course) you will get the nearest
neighbor, leaving you with the value of 1 (center) out of the 400 source
pixels. It could be what someone's after, but most often its not.

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