[postgis-users] projection management

[Frank Warmerdam]

Brent Wood wrote:
>> Thanks for the reply, that clarifies matters nicely.  I think I'm
>> understanding also that setsrid(the_geom, the_srid) rolls that srid
>> right into the binary representation of the geometry.  I wonder if it
>> might be desirable/possible in a future version, then, to have
>> astext(the_geom) output the srid along with the text representation of
>> the geometry.  
> 
> I believe WKT is defined by the OGC, as part of the SFS spec that PostGIS
> complies with. EWKT was created to address this limitation of the WKT format.
> It is not likely that OGC will revise the SFS/WKT spec, so it is also unlikely
> that PostGIS will modify the string returned by WKT. 
> 
> So if you require a SRID in the output, use EWKT instead of WKT.
> 
> Standards are usually a good thing :-)

Brent,

In fact, there is an OGC Simple Features Revision Working Group which will
likely be issuing updated specifications for SF-SQL and the corresponding
WKT geometry format.  Likely additions to WKT include curves, and labels
as well as "Z" and "M" vertex values.

Of course your basic point is correct.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org