[postgis-tickets] [PostGIS] #5006: ST_Transform: Support PROJ pipelines

[PostGIS]

#5006: ST_Transform: Support PROJ pipelines
-------------------------+-----------------------------
 Reporter:  cdestigter   |      Owner:  pramsey
     Type:  enhancement  |     Status:  new
 Priority:  medium       |  Milestone:  PostGIS Fund Me
Component:  postgis      |    Version:  master
 Keywords:               |
-------------------------+-----------------------------
 I hoped to be able to use a [https://proj.org/operations/pipeline.html
 #the-pipeline-operator PROJ pipeline string] to apply a non-default
 transform between two coordinate systems.

 Usage might look like this:

 {{{
 #!sql
 select st_asewkt(
     ST_TransformPipeline(
         'SRID=4283;POINT(143.0 -37.0)'::GEOMETRY,
         '+proj=pipeline +step +proj=axisswap +order=2,1 +step
 +proj=unitconvert +xy_in=deg +xy_out=rad +step +proj=hgridshift
 +grids=au_icsm_GDA94_GDA2020_conformal_and_distortion.tif +step
 +proj=unitconvert +xy_in=rad +xy_out=deg +step +proj=axisswap +order=2,1'
     )
 );
 }}}


 Ideally the EPSG code for the transform would be usable too, e.g.

 {{{
 #!sql
 select st_asewkt(
     ST_TransformPipeline(
         'SRID=4283;POINT(143.0 -37.0)'::GEOMETRY,
         'EPSG:8447'
     )
 );
 }}}

 I'm not sure if supporting pipelines defined by other authorities is a
 concern (maybe?), and if so I'd probably steer clear of supporting an
 integer parameter for the EPSG code, otherwise we'll need a lookup table:

 {{{
 #!sql
 -- this would probably need a lookup table, maybe best to avoid?
 select st_asewkt(
     ST_TransformPipeline(
         'SRID=4283;POINT(143.0 -37.0)'::GEOMETRY,
         8447
     )
 );
 }}}

-- 
Ticket URL: <https://trac.osgeo.org/postgis/ticket/5006>
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