[postgis-users] Is GeomUnion() now ST_Union()?

Andy Anderson aanderson at amherst.edu
Fri May 16 07:51:23 PDT 2008


>  select a.gid, geomunion(b.the_geom)

Being new to PostGIS, I've been looking at other people's code  
snippets and trying to figure out what they do. I'm a bit mystified  
by "geomunion()", though, as it's not in the PostGIS docs, though  
there are many references to it in the mailing list archives. Is this  
the same as "ST_Union()" <http://postgis.refractions.net/docs/ 
ch06.html#id2595344>?

I see a statement at the beginning of Chapter 6 that "PostGIS has  
begun a transition from the existing naming convention to an SQL-MM- 
centric convention. As a result, most of the functions that you know  
and love have been renamed using the standard spatial type (ST) prefix."

 From this I can conclude that ST_Union() used to be Union(), and in  
that section it says "NOTE: this is renamed from "union" because  
union is an SQL reserved word" which implies that even from very  
early on it was different than Union(), perhaps GeomUnion(). But if  
this is the case, this name change should also be explicitly documented.

If there was a general renaming from Geom* to ST_*, that is also not  
documented that I can find.

Confirmation requested, and if necessary documentation for all such  
unusual name changes.

Thanks,

-- Andy




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