I'm using gdalwarp for resampling a GeoTiff from its original resolution (5m, 5m) to a target resolution (10m, 10m):
gdalwarp -tr 10 -10 input.tif output.tif
I'm using a negative yres because when I open the file on QGIS, or if I use gdalinfo, I get a pixel size equal to 5, -5 for the source raster.
My question is: is it correct to use a negative yres with gdalwarp? I also tried -tr 10 10, but the results seems to be the same of the case in which I use -tr 10 -10. In both cases gdalinfo and QGIS display (10,-10) as the pixel size.