[GRASS-dev] proj -l

[Glynn Clements]

Hamish wrote:

> I just learned of the "proj -l" command from PROJ.4. (post on Proj.4 ml)
> 
>        -l[p|P|=|e|u|d]id
>               List projection identifiers with -l,  -lp
>               or  -lP  (expanded)  that can be selected
>               with   +proj.    -l=id   gives   expanded
>               description   of   projection  id.   List
>               ellipsoid identifiers with -le, that  can
>               be  selected  with  +ellps,  -lu  list of
>               cartesian  to  meter  conversion  factors
>               that  can  be selected with +units or -ld
>               list of datums that can be selected  with
>               +datum.
> 
> 
> Maybe it would be useful in a future auto-gen g.setproj GUI wizard [if
> GRASS moves to "full" use of proj.4].

It doesn't really help. -l alone only lists the projections, not which
parameters they accept/require. -lP lists the parameters, but the
format isn't quite machine-readable (it's not far off, but a miss is
as good as mile in this context). No option lists the default values.

Also, there's no guarantee that whichever "proj" executable comes
first in the path uses the same libproj library as GRASS.

For the foreseeable future, we'll need to maintain our own metadata.

-- 
Glynn Clements <glynn at gclements.plus.com>