[PROJ] Finding not implemented projections

[Javier Jimenez Shaw]

Thank you Even.
Doing it only once per projectionMethodName is very fast.

Just as information, those are the 6 "invalid" projection methods in PROJ
9.7.1 (with the first code catching them)

code: 2218 projection: Lambert Conic Conformal (West Orientated) ** invalid
**
code: 2963 projection: Bonne (South Orientated) ** invalid **
code: 2985 projection: Polar Stereographic (variant C) ** invalid **
code: 22300 projection: Tunisia Mining Grid ** invalid **
code: 22700 projection: Lambert Conic Near-Conformal ** invalid **
code: 32600 projection: Transverse Mercator Zoned Grid System ** invalid **


On Thu, 26 Feb 2026 at 15:34, Even Rouault <even.rouault at spatialys.com>
wrote:

> Javier,
>
> nothing comes to mind but trying proj_as_proj_string() on them, but that
> will be quite slow if you want to filter the whole list of CRS and do
> that on every CRS. That said, you could pick up one CRS for each of the
> value of projection_method_name to limit the number of CRS instantiation.
>
> Or add a new C function based on using one of
> osgeo::proj::operation::getMapping()  from
> src/iso19111/operation/parammappings.hpp
>
> Even
>
> Le 26/02/2026 à 11:29, Javier Jimenez Shaw via PROJ a écrit :
> > Hi
> >
> > Today I met "by accident" EPSG:3053
> > https://spatialreference.org/ref/epsg/3053/
> > looking for a westing-northing system.
> >
> > I realized that the projection "Lambert Conic Conformal (West
> > Orientated)" is not implemented (all fine, I don't want it to be
> > implemented).
> >
> > What I want to know is which CRSs from the catalog do not have an
> > implemented projection, to avoid using them.
> > We are using "proj_get_crs_info_list_from_database" to get the list of
> > all the systems (13722). It includes the field
> > "projection_method_name" (a string).
> > Is there any function in C or C++ API to know if such a method is
> > implemented? Doing a quick search in spatialreference I see there are
> > 53 methods in total nowadays.
> > I don't want to hardcode that list in my code, in case anything
> > changes in the future.
> >
> > Thank you.
> >
> > Cheers
> > Javier.
> >
> > _______________________________________________
> > PROJ mailing list
> > PROJ at lists.osgeo.org
> > https://lists.osgeo.org/mailman/listinfo/proj
>
> --
> http://www.spatialys.com
> My software is free, but my time generally not.
>
>
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