[PROJ] idea: projection metadata

[Nyall Dawson]

On Wed, 26 Feb 2020 at 07:30, Even Rouault <even.rouault at spatialys.com> wrote:
>
> Nyall,
>
> > Just wanted to bounce an idea I had recently. I'd love to see proj
> > gain an API for querying projection metadata, specifically:
> >
> > - retrieve a list of all available projection methods
> > - given a a projection, retrieve the description, classification,
> > available forms, defined area, etc metadata listed at the top of
> > projection documentation page
>
> "defined area" wouldn't be directly possible on a projection method, as this
> depends on the value of the projection parameters.
> And it is tricky to define. There is the conventional/typical area of use (as
> typically found in the EPSG database in the 'area_of_use_code' column of the
> 'epsg_coordoperation' table), but sometimes the implementation is accurate
> enough so that you can use it on whole Earth with excellent numeric accuracy
> (like tmerc now).

I'm referring to the "defined area" described at the top of pages like
https://proj.org/operations/projections/ccon.html


> > Does this sound like a desirable inclusion in the proj API?
>
> I think that would be a nice addition.
>
> If we push the idea to its limits, we could even consider generating the
> documentation pages entirely, or substantially, from that (but would require
> to embed substantial prose & formulas sometimes)
>
> > I'm willing to chip away at this in spare time, but would love some
> > pointers on a recommended approach to take to implement it...
>
> I don't have a ready-made design for this, but some thoughts to consider to
> design one:
>

*snip* thanks! I'll digest this ...

Nyall