Even Rouault

Results 1299 comments of Even Rouault

> Gdalwarp with `-r lanczos` can cause aliased edges. you'll have to explain more the issue with some highlighting to show where you see something wrong. I can't even notice...

> It has 160GB so I will provide a description where to download it and create it. you can also try to use gdal_translate -projwin or -srcwin to create a...

> and the issue will not reproduce. actually it does, for example when comparing the cubicspline vs lanczos around coordinate 2365033.68, 6240237.04 in EPSG:3857

I've made a significant breakthrough in debugging this. The following patch disabling the Lanczos optimized code path (used since 12 years...) seems to fix the aliasing issue. ``` diff --git...

> Please post a screenshot so I could see your result Lanczos: ![image](https://github.com/user-attachments/assets/101268bc-7f6f-4b84-bc5b-d135229c9b62) vs cubic spline: ![image](https://github.com/user-attachments/assets/41276dae-a21c-4ec3-b3d5-1233249f0446)

Workaround: if just reprojecting without trying to downsample/oversample, adding ``-wo XSCALE=1 -wo YSCALE=1`` will avoid the issue

The crash also happens without Valgrind. It occurs around https://github.com/OSGeo/gdal/blob/master/frmts/exr/exrdataset.cpp#L131

> You'd better mark them as `[ci skip]` in the commit message true, but it must only be used for really trivial changes, like a typo. Anything more involved related...

nipicky=true enabled in https://github.com/OSGeo/gdal/pull/12715 but with mass suppression for all Python related warnings