[FWTools] Dumping to wkt for a .prj file - meter vs. metre

Frank Warmerdam warmerdam at pobox.com
Wed Oct 25 13:11:13 EDT 2006


David Fawcett wrote:
> Yep, I understand why it might be spelled that way, I am just curious 
> why the 9 billion pound gorilla of GIS can't seem to speak something 
> other than 'American'. 

David,

I believe the problem is partly that the OGC specifications dealing with
WKT are rather weak (underspecified), and that ESRI has taken a rather
name oriented approach to recognizing some things (most noticably units,
and datums), rather than examining the parameterized values.

I'd add that I *think* the ESRI Projection Engine implementation of WKT
predated the Simple Features specification which include WKT.  Realistically
the industry ought to have aimed for ESRI compatibility where the
specification was ambiguous but somehow that didn't happen.  Certainly I
didn't realize there was such a thing as ESRI WKT when I started work on
WKT support in OGR and so I failed to aim for early compatability.  Instead
I find myself fixing things up after the fact now.

> By the way, OpenEv seems to recognize the units just fine....

OGR and OGR based applications *try* to use the parametric values as possible.

Best regards,
-- 
---------------------------------------+--------------------------------------
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



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