[postgis-devel] Canonical Text Rep for empty Geometry Collections

[strk at refractions.net]

Added support for GEOMETRYCOLLECTION(EMPTY):

--- wktparse.y  10 Jan 2005 09:47:14 -0000      1.5
+++ wktparse.y  17 Jan 2005 12:15:13 -0000
@@ -119,5 +119,5 @@
 point_4d : VALUE VALUE VALUE VALUE {alloc_point_4d($1,$2,$3,$4); };

-empty : EMPTY  {alloc_empty(); } ;
+empty : EMPTY  {alloc_empty(); } | LPAREN EMPTY RPAREN {alloc_empty(); } ;
 %%

--strk;

On Mon, Jan 17, 2005 at 12:55:30PM +0100, strk at refractions.net wrote:
> On Mon, Jan 17, 2005 at 12:49:36PM +0100, Markus Schaber wrote:
> > Hi,
> > 
> > What is the correct Canonical Text Representation for empty Geometry
> > Collections?
> 
> 'GEOMETRYCOLLECTION EMPTY'
> 
> (actually '<anytype> EMPTY' works)
> 
> 
> > With old PostGIS 0.8, the following worked:
> > 
> > logigis=#  select 'GEOMETRYCOLLECTION(EMPTY)'::geometry;
> >              geometry
> > -----------------------------------
> >  SRID=-1;GEOMETRYCOLLECTION(EMPTY)
> > (1 Zeile)
> > 
> > But with new PostGIS 1.0 CVS, it does not work any more:
> > 
> > lwgeom=# select 'GEOMETRYCOLLECTION(EMPTY)'::geometry;
> > ERROR:  parse error - invalid geometry
> > lwgeom=# select 'SRID=-1;GEOMETRYCOLLECTION(EMPTY)'::geometry;
> > ERROR:  parse error - invalid geometry
> > 
> > This makes me believe that we currently cannot restore old dumps that
> > contain empty collections.
> 
> Yes, this is an issue. I'll try at making the new parser
> accept that as well.
> 
> --strk;
> 
> > 
> > HTH,
> > Markus
> 
> 
> 
> > _______________________________________________
> > postgis-devel mailing list
> > postgis-devel at postgis.refractions.net
> > http://postgis.refractions.net/mailman/listinfo/postgis-devel
> 
> 
> -- 
> 
> For standing up against patentability of software,
> 
>   Thank You, Poland!
> 
> Read the intervention:    http://kwiki.ffii.org/ConsPolon041221En
> Send your thanks:         thankyoupoland.info
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-- 

For standing up against patentability of software,

  Thank You, Poland!

Read the intervention:    http://kwiki.ffii.org/ConsPolon041221En
Send your thanks:         thankyoupoland.info
Read/do more:		  http://www.noepatents.org/