Doc: Add table of contents for pipeline steps and document missing steps

doc/source/gdal_rtd/static/css/gdal.css

@@ -357,3 +357,7 @@ table.top-aligned-table td p {
     line-height: 140% !important;
 }
 
+/** two-column TOC used for pipeline steps */
+.steps-toc ul {
+    columns: 2;
+}

doc/source/programs/gdal_pipeline.rst

@@ -44,50 +44,93 @@ all other steps can potentially be used several times in a pipeline.
 
         $ gdal pipeline ! read in.tif ! footprint ! buffer 20 ! write out.gpkg --overwrite
 
+Steps
+-----
+
 For steps that have both *raster* data type as input and output, consult :ref:`gdal_raster_pipeline`.
 For steps that have both *vector* data type as input and output, consult :ref:`gdal_vector_pipeline`.
 
-The following steps accept raster input and generate vector output:
-
-* contour
+The table below lists steps that convert between raster and vector data.
+
+.. list-table::
+   :header-rows: 1
+   :widths: 40 60
+
+   * - Step
+     - Direction
+   * - :ref:`contour <pipeline-contour>`
+     - Raster → Vector
+   * - :ref:`footprint <pipeline-footprint>`
+     - Raster → Vector
+   * - :ref:`pixel-info <pipeline-pixel-info>`
+     - Raster → Vector
+   * - :ref:`polygonize <pipeline-polygonize>`
+     - Raster → Vector
+   * - :ref:`grid <pipeline-grid>`
+     - Vector → Raster
+   * - :ref:`rasterize <pipeline-rasterize>`
+     - Vector → Raster
+   * - :ref:`tee <pipeline-tee>`
+     - Vector → Raster
+
+.. _pipeline-contour:
+
+contour
+*******
 
 .. program-output:: gdal pipeline --help-doc=contour
 
 Details for options can be found in :ref:`gdal_raster_contour`.
 
-* footprint
+.. _pipeline-footprint:
+
+footprint
+*********
 
 .. program-output:: gdal pipeline --help-doc=footprint
 
 Details for options can be found in :ref:`gdal_raster_footprint`.
 
-* pixel-info
+.. _pipeline-grid:
+
+grid
+****
+
+.. program-output:: gdal pipeline --help-doc=grid
+
+Details for options can be found in :ref:`gdal_vector_grid`.
+
+.. _pipeline-pixel-info:
+
+pixel-info
+**********
 
 .. program-output:: gdal pipeline --help-doc=pixel-info
 
 Details for options can be found in :ref:`gdal_raster_pixel_info`.
 
-* polygonize
+.. _pipeline-polygonize:
+
+polygonize
+**********
 
 .. program-output:: gdal pipeline --help-doc=polygonize
 
 Details for options can be found in :ref:`gdal_raster_polygonize`.
 
-The following steps accept raster vector and generate raster output:
-
-* grid
-
-.. program-output:: gdal pipeline --help-doc=grid
-
-Details for options can be found in :ref:`gdal_vector_grid`.
+.. _pipeline-rasterize:
 
-* rasterize
+rasterize
+*********
 
 .. program-output:: gdal pipeline --help-doc=rasterize
 
 Details for options can be found in :ref:`gdal_vector_rasterize`.
 
-* tee
+.. _pipeline-tee:
+
+tee
+***
 
 .. program-output:: gdal pipeline --help-doc=tee-raster