[postgis-users] prj and SRID relation

Norman Vine nhv at cape.com
Thu Oct 14 10:50:09 PDT 2004

Frank Warmerdam writes:
> Paul Ramsey wrote:
> > Frank Warmerdam wrote:
> > 
> >> I would add that implementing WKT to PROJ.4 translation isn't
> >> terribly hard, but it is significantly harder to keep up with
> >> variations in WKT input from different sources, especially ESRI.
> >> Have to maintain multiple copies of this sort of stuff would be quite
> >> a hassle for all involved.  My maintaining one copy of it is already
> >> quite a hassle!
> > 
> > 
> > Just by way of an aside, does OGR ever use the WKT in the absence of 
> > proj4? I just find it odd that the library that needs the ability to 
> > parse the serialized form (proj4) is not the library that actually has 
> > the ability. Could you be persuaded (somehow :) to move the WKT support 
> > to proj4 and deprecate the OGR side, thereby maintaining a single point 
> > of maintenance, but having that point be proj4?
> Paul,
> There are rare circumstances where the OGRSpatialReference WKT support is
> used without any relationship to PROJ.4, including within FME to implement
> their WKT support.  Also I have had at least one client substitute in a
> different projections library in place of PROJ.4.  Also, GDAL and related
> tools can provide reasonable coordinate system descriptions now even if
> PROJ.4 is not installed.
> Based on that, I am hesitant to try and restructure everything to put the
> OGRSpatialReference WKT logic all down in PROJ.4.  Keep in mind that WKT
> is substantially more expressive than PROJ.4 format.
> There is also some interest from an influential member of the PROJ.4
> community to avoid dumping alot of extra complexity into PROJ.4.


< thinking publically >
I wonder if it would be worth the effort to refactor GDAL / OGR further
into CPL / SRS / OGR / GDAL libraries
< /done thinking >



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