[geos-devel] WKT EMPTY

Martin Davis mbdavis at VividSolutions.com
Tue Apr 19 17:19:28 EDT 2005

Can't resist adding my 2c worth...

To my mind, it's pretty clear that the intent of the syntax spec is that
words in all UPPERCASE are intended to be literals in the WKT language.
In this case, the representation of an empty Point is


This interpretation also has the advantage of being unambiguous and
explicit.  If the representation was POINT only, there are two

- an empty Point
- an incorrect Point representation, with the actual coordinate missing

I guess the spec authors may have the final word, but until they weigh
in I'd vote for sticking with POINT EMPTY.

Martin Davis, Senior Technical Architect
Vivid Solutions Inc.      www.vividsolutions.com
Suite #1A-2328 Government Street Victoria, B.C. V8T 5G5
Phone: (250) 385 6040 - Local 308 Fax: (250) 385 6046

> -----Original Message-----
> From: geos-devel-bounces at geos.refractions.net 
> [mailto:geos-devel-bounces at geos.refractions.net] On Behalf Of 
> Frank Warmerdam
> Sent: April 19, 2005 1:58 PM
> To: GEOS Development List
> Subject: [geos-devel] WKT EMPTY
> Folks,
> David Arctur is uncertain about the WKT EMPTY issue himself, so at 
> this point we have no clear answer on what is right or wrong. 
>  He has agreed that this point should be clarified in future 
> versions of the 
> simple features spec by the revision working group. 
> But that doesn't help us here and now. 
> PS. Forgive me for changing the subject - I think the GEOS 
> Exceptions subject line was getting a little to general-purpose. 
> 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    | Geospatial 
> Programmer for Rent
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