Doc: Add pipeline examples of raster clipping

[geographika]

Adds the following to the docs:

• a new pipeline example showing a mixed raster/vector pipeline with nesting (following the fix provided in Failing mixed raster vector pipeline #14637). I added in a diagram, and the resulting output image to brighten up the docs (it could be removed, but is only 26KB): preview
• also added 2 other examples of clipping a raster using vector features: preview
• linked to all 3 from the cookbook: preview

The gdal_vector_pipeline.rst page was missing one of its final step options export-schema. There are a few other steps that are missing. I can add these in manually to the pipeline pages, but maybe we want to try and automate which tools are available in pipelines?

See "potential steps" sections at https://gdal.org/en/latest/programs/gdal_vector_pipeline.html and https://gdal.org/en/latest/programs/gdal_raster_pipeline.html (and also https://gdal.org/en/latest/programs/gdal_pipeline.html#gdal-pipeline). Thoughts @dbaston @rouault ?

[dbaston]

but maybe we want to try and automate which tools are available in pipelines?

I'd probably have gdal pipeline link to gdal vector pipeline and gdal raster pipeline for a list of the available steps, rather than duplicating them.

[geographika]

Maybe also show how the same operation could be done by reading the vector as the first step and piping it into raster clip.

@dbaston - is this possible? I think it has to use _PIPE_, but I can't get it to work (seems like vector clip is used?)
My attempt below:

gdal pipeline \
  ! read natural_earth_vector.gpkg --layer "ne_50m_admin_0_countries" \
  ! filter --where "ADMIN='Romania'" \
  ! buffer --distance=1 \
  ! clip --input "NE2_50M_SR_W.tif" --like _PIPE_ \
  ! write romania.png  --overwrite

ERROR 4: `NE2_50M_SR_W.tif' not recognized as being in a supported file format

[geographika]

but maybe we want to try and automate which tools are available in pipelines?

I'd probably have gdal pipeline link to gdal vector pipeline and gdal raster pipeline for a list of the available steps, rather than duplicating them.

The pipeline page only contains descriptions of steps common to both vector and raster. I guess the steps won't change often so it might be easiest to manually update them. Or maybe use the output of gdal vector pipeline --help and gdal raster pipeline --help (and gdal pipeline --help) although that might be too verbose.

[rouault]

is this possible? I think it has to use _PIPE_, but I can't get it to work (seems like vector clip is used?)

I'm looking at that. The pipeline building logic is confused here and wrongly selects the vector clip algorithm.

[rouault]

'm looking at that

addressed in #14663

[geographika]

I have added a buffer step, and also an equivalent example using __PIPE__ as suggested by @dbaston.
I need to check the __PIPE__ example works with the latest GDAL build and the fix from @rouault in #14663, and will then mark as ready to review.

[geographika]

@rouault - did you mean to close this as well as #14663 ?

[rouault]

did you mean to close this as well as #14663 ?

ah sorry, my commit message only mentioned fixing this particular comment #14661 (comment), but github decided to close this whole PR. Re-opening it...

[geographika]

__PIPE__ example tested on latest Windows / Conda and Linux / Docker - all work fine with #14663.

PR ready from my side.