gdalwarp 1.10.1 : downsampling with 'average' option, pixel definition makes faulty aggregation

[bmr9]

Just checked gdalwarp downsampling with '-r average' option, for SAME input and output resolution.

Input: $ gdalwarp -tr 1 1 -r average mytif.TIF mytif_lowres_1.TIF

Actual result: mytif.TIF and mytif_lowres_1.TIF present different values and a shift in values to the upper left corner of the image.

Expected result: mytif.TIF and mytif_lowres_1.TIF should present same values.

More examples: similar behaviour when changing resolution (-tr 2 2, for instance)

Additional information:

mytif.TIF array-like values are:

[[ 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.]

[ 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.]

[ 0. 0. 1. 1. 1. 1. 1. 1. 0. 0.]

[ 0. 0. 1. 1. 1. 1. 1. 1. 0. 0.]

[ 0. 0. 1. 1. 1. 1. 1. 1. 0. 0.]

[ 0. 0. 1. 1. 1. 1. 1. 1. 0. 0.]

[ 0. 0. 1. 1. 1. 1. 1. 1. 0. 0.]

[ 0. 0. 1. 1. 1. 1. 1. 1. 0. 0.]

[ 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.]

[ 0. 0. 0. 0. 0. 0. 0. 0. 0. 0.]]

mytif_lowres_1.TIF array-like values are:

[[ 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. ]

[ 0. 0.25 0.5 0.5 0.5 0.5 0.5 0.25 0. 0. ]

[ 0. 0.5 1. 1. 1. 1. 1. 0.5 0. 0. ]

[ 0. 0.5 1. 1. 1. 1. 1. 0.5 0. 0. ]

[ 0. 0.5 1. 1. 1. 1. 1. 0.5 0. 0. ]

[ 0. 0.5 1. 1. 1. 1. 1. 0.5 0. 0. ]

[ 0. 0.5 1. 1. 1. 1. 1. 0.5 0. 0. ]

[ 0. 0.25 0.5 0.5 0.5 0.5 0.5 0.25 0. 0. ]

[ 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. ]

[ 0. 0. 0. 0. 0. 0. 0. 0. 0. 0. ]]

[bmr9]

Output raster file after "gdalwarp -tr 1.0 1.0 mytif.TIF mytif_lowres_1.TIF"

[bmr9]

Original raster file (TIF): resolution 1.0 1.0

[bmr9]

Bug present in linux machines (tested red hat and ubuntu) Bug not present in windows

[Even Rouault]

I can't replicate the issue with trunk. I believe this has been fixed by #5311.