[GRASS-dev] [PROJ] GRASS GIS + PROJ 6 + GDAL 2.5

[Even Rouault]

On vendredi 8 mars 2019 17:01:57 CET Markus Metz wrote:
> On Fri, Mar 8, 2019 at 12:41 PM Even Rouault <even.rouault at spatialys.com>
> 
> wrote:
> > On vendredi 8 mars 2019 12:27:37 CET Markus Metz wrote:
> > > On Fri, Mar 8, 2019 at 10:49 AM Roger Bivand <Roger.Bivand at nhh.no>
> 
> wrote:
> > > > Since rgdal::make_EPSG() is facing the same problems of listing
> 
> tabulated
> 
> > > > EPSG fields as g.proj -l, I was very happy to see Markus' code in
> > > > g.proj/main.c mentioned in this thread, and have used this approach in
> 
> https://r-forge.r-project.org/scm/viewvc.php/pkg/src/proj_info6.cpp?view=mar
> > > kup&root=rgdal
> > > 
> > > > However, there are plenty of messages such as: "proj_as_proj_string:
> > > > Unsupported conversion method: Lambert Conic Conformal (West
> > > 
> > > Orientated)". I
> > > 
> > > > haven't installed GRASS trunk with PROJ6, so I can't see whether
> 
> g.proj -l
> 
> > > > also sees the same messages.
> > > 
> > > I get the same messages with g.proj, but no error code from PROJ error
> > > handlers.
> > > 
> > > > If it does, maybe we could ask on the proj list
> > > 
> > > yes, we should ask. For now g.proj is ignoring those codes for which no
> > > proj string can be retrieved.
> > 
> > I'm not sure what the question is exactly :-)
> 
> My question is, what should GRASS do with a SRS without proj string? The
> best answer is probably: use WKT instead of a proj string. But most of the
> GRASS code uses (for historical reasons) some form of proj syntax, also to
> store projection info for a GRASS location. If there is no proj string,
> GRASS thinks there is no SRS and falls back to a generic xy system which is
> not always correct.

The WKT will not help here. You will be able to get here, but you won't be 
able to do coordinate transformation with it. This is just that this EPSG 
method is not implemented or mapped to a PROJ projection method


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