[postgis-devel] text(lwgeom)

strk at refractions.net strk at refractions.net
Tue Dec 14 03:01:04 PST 2004


Hi Carl.
I've added a geometry::text implicit cast in CVS.
Thanks for pointing that out.
--strk;

On Mon, Dec 13, 2004 at 09:24:48PM -0500, Carl Anderson wrote:
> 
> I believe that text(lwgeom) is necessary if we want a WKB-ish CSTRING 
> format to be the default
> representation for a geometry in scripting.
> 
> Inside PLPGSQL I have found that I need to
> 
> FOR a in EXECUTE \'select mytab.the_geom
>          from mytab,
>                 (select geometry(\'||quote_literal(text(GEOM))||\') as 
> the_geom ) as e
>              where
>                   mytab.the_geom && e.the_geom and
>                   intersects(mytab.the_geom, e.the_geom)\'  LOOP
>       blah;
>       blah;
> END LOOP; 
>      
> in this instance I expect that text(GEOM) ==  the CSTRING rep of a LWGEOM
> but in a TEXT wrapper. 
> 
> This would cause
>       text(LWGEOM)          text rep of CSTRING representation
>       astext(LWGEOM)       OGIS WKT rep
>       asbinary(LWGEOM)   OGIS WKB rep
> 
> I can't
>   setsrid(geometry(asbinary(\'||asbinary(GEOM)||\')),\'||mysrid||\')\'
> because there does not exist a clear path from BYTEA to TEXT or BPCHAR;
> And the precision issues with WKT vs WKB need to be quickly eliminiated when
> trakicg down a problem.
> 
> Such a text(geometry) would simply be
> 
> text-izing LWGEOM_out as the attached patch exhibits.
> 
> C.
> 
> 
> ps.
> 
> postgis-devel seems dead-ush.  Should this discussion occur in 
> postgis-users??
> 
> 


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