[PROJ] Problems with EPSG:1236 - (AGD84 to WGS 84 (2))

[Even Rouault]

>
> EPSG:1236, AGD84 to WGS 84 (2) is missing. This has an accuracy of  5, 
> same as EPSG:15789.
>
>
>
> Question 1:
> Is this to be considered as a bug, or is it a logical explanation? I 
> have a couple of more similar examples.

You'll get it with the --show-superseded flag of projinfo:

projinfo -s AGD84 -t "WGS 84" --summary --spatial-test intersects 
--show-superseded
Candidate operations found: 5
EPSG:1669, AGD84 to WGS 84 (7), 3.0 m, Australia - Queensland, South 
Australia, Western Australia, federal areas offshore west of 129°E.
EPSG:1109, AGD84 to WGS 84 (1), 4.0 m, Australia - Queensland, South 
Australia, Western Australia, federal areas offshore west of 129°E.
EPSG:15789, AGD84 to WGS 84 (8), 5.0 m, Australia - Queensland, South 
Australia, Western Australia, federal areas offshore west of 129°E.
EPSG:1236, AGD84 to WGS 84 (2), 5.0 m, Australia - Queensland, South 
Australia, Western Australia, federal areas offshore west of 129°E.
DERIVED_FROM(EPSG):15785, AGD84 to WGS 84 (9), 2.9 m, Australia - 
Queensland, South Australia, Western Australia, federal areas offshore 
west of 129°E., at least one grid missing

EPSG:1236, AGD84 to WGS 84 (2) has been superseded per EPSG:1669, AGD84 
to WGS 84 (7)

The supersession is recorded in the supersession table of proj.db and 
also shows in the remark of EPSG:1236

     REMARK["""Higgins parameters"". Replaced by AGD84 to GDA94 (2) 
(code 1280) and AGD84 to WGS 84 (7) (code 1669). Note: AGD84 officially 
adopted only in Queensland, South Australia and Western Australia."]]

>
> Question 2:
> On the other side, I am able to get the pipeline going from 4203 to 
> 4326 (AGD84 to WGS 84 (2)). by using:
> Transformer.from_pipeline(f"urn:ogc:def:coordinateOperation:EPSG::1236")
>
> As the API I develop delivers transformation pipelines in both 
> directions, where coordinates are not always given(optional), It's 
> easy to get the pipeline in both directions using TransformerGroup.
>
> I am considering using the urn definition + Transformer.from_pipeline 
> instead, but struggle to find a way to get the reverse pipeline (from 
> EPSG:4326 to EPSG:4203 (EPSG:1236)).
> Someone who can help on how this can be done?

PROJ itself has a proj_coordoperation_create_inverse() method, but it 
doesn't seem to be used by pyproj. Something to potentially raise to 
https://github.com/pyproj4/pyproj

Even


-- 
http://www.spatialys.com
My software is free, but my time generally not.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/proj/attachments/20230310/69b870cf/attachment.htm>