[gdal-dev] RFC 73 (aka gdalsrsbarn) available for review

[Even Rouault]

Hi Markus,

Thanks for your feedback

> Regarding WKT2, a remark from a GRASS GIS developer being a user of
> GDAL/PROJ:
> 
> I understand that WKT2 is long overdue and thus should be pushed as much
> and as early as possible. Otherwise it would take a long time and a rather
> long and painful transition process to switch to WKT2. My suggestion is to
> try to keep the painful transition process as short as possible and switch
> to WKT2 ASAP. People like to stick to what they have and what they know, so
> if something better is available, some convincing is needed.

So you would be in favor of making OSRExportToWkt() default to WKT2 ? 
(probably WKT2:2018 while we are at it ? Not just the output of gdalinfo / 
ogrinfo utilities.
I was shy in doing so, because it will likely require updating a good deal of 
GDAL autotests, but oh well...

What annoys me a bit more is the case of XML files like GDAL VRT, OGR VRT or 
.aux.xml that contains serialized SRS and that I wanted to be backward 
compatible with older GDAL versions as much as possible.

> 
> Backwards compatibility wrt reading WKT1 needs to be maintained because
> already existing datasets must still be readable.

Yes this is of course done. Export to older WKT versions will likely still be 
needed for some formats too

> Regarding the BBOX, it should be made clear that the reported extents are a
> suggestion, not a limitation.

The semantics is a bit fuzzy. The WKT standard mentions "Extent describes the 
spatial and/or temporal applicability of a CRS, datum, datum ensemble, 
coordinate operation or Bound CRS". For a CRS, you can go beyond depending on 
the numeric stability of the implementation of the projection method (in case 
of a projected CRS). For a coordinate operation, if it involves a grid, the 
BBOX should be interpreted in a rather strict way (that's what PROJ master 
does internally when computing the most appropriate coordinate transformation 
given all the constraints it is given)

Even

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