The image below shows part of a peninsula on the Australian island of Tasmania. The black pixels are 9" climate data with GDA94 (EPSG:4283) SRS, projected by QGIS on the fly to Australian Albers (EPSG:3577). The purple (pink?) and blue pixels are the same data projected to a 250 m grid in Australian Albers with gdalwarp, using "cubicspline" and "cubic" resampling methods, respectively, e.g. with:
gdalwarp -multi -tr 250 250 -s_srs "EPSG:4283" -t_srs "EPSG:3577" -r "cubicspline" -dstnodata "-9999" in.flt out.tif
I've used GDAL 1.11.1 for the above.
Why do the data resampled with "cubicspline" extend beyond the cells of the original data, and is there a way to make the behaviour consistent with that of "cubic"?
Comments on which approach is more appropriate when resampling climate data are also welcome.