[postgis-devel] WKT Raster: Back from RT_ to ST_

[Paragon Corporation]

Strk,
Your code wouldn't just work anyway.  There is enough variant between the
IBM, MS, Oracle, PostGIS, ArcSDE (dear I mention MySQL here) versions that
the "just work" idea doesn't "just work".  At best you are talking about
portability of knowledge.  It would just "sort of work".  

For example MS uses camel case so its STIntersects not ST_Intersects.
Oracle based on my understanding if you use ST_GeomFromText you get a
generic geometry object, but if you use ST_PolygonFromText you get a
qualified Polygon object with completely different structure. Then Oracle
has this whole ordinate array thing going on. I think IBM comes closest to
being cross compatible with PostGIS but they allow mixed SRIDs I think and
silently convert. Oracle ST_Distance takes unit type as an arg. So that's
why I'm not too too bothered that we use ST_ a little more than we should.
  
The reason I like the overloading idea for RASTER is that if you had written
code to work with PostGIS geometries and later decided you want it to work
with RASTER, I think its an easier exercise if RASTER uses the same names.
Otherwise you'd have to macro replace the code everywhere.  You'd probably
still need to test and depending on the language rewrite since the outputs
are different, but my feeling is that it's a bit of an easier task if the
names are the same.

Thanks,
Regina



 

-----Original Message-----
From: postgis-devel-bounces at postgis.refractions.net
[mailto:postgis-devel-bounces at postgis.refractions.net] On Behalf Of strk
Sent: Friday, April 03, 2009 4:39 AM
To: PostGIS Development Discussion
Subject: Re: [postgis-devel] WKT Raster: Back from RT_ to ST_

On Thu, Apr 02, 2009 at 08:26:38PM -0400, Paragon Corporation wrote:
> Yap ST_ thingy should have been left for only ISO stuff.  Right now I 
> feel sort of torn since the damage has already been done; seems like a 
> lot of effort to correct the wrong.  Maybe we can revisit in 2.0.
> 
> I do like the idea of overloading ST for raster though, but I think 
> Paul was dead set against the idea because it would break OGC
compatibility.

Actually, I think anyone using postgis-specific things should use the
version with no ST_ prefix. When you use ST_ it's because you're hoping your
code will "just work" with any ISO-compliant thingy.

If you're using rasters, and they are not ISO-standard, you should use
Intersect() for both rasters and vectors. You know you're talking to postgis
and not a generic ISO standard SF dbms.

--strk; 

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