[postgis-devel] WKT form(s) of MULTIPOINT

[Paul Ramsey]

Well, that's embarrassing. We don't implement either spec, we follow
SQL/MM, but it has the same BNF as the above. We got the initial
sparser representation at the dawn of time, and I guess never changed
it. I would have thought it would happen at 2.0 when the wkt emitter
was re-written, but apparently I missed it (unless the archives show I
did it on purpose)

P.

On Wed, Dec 4, 2013 at 7:31 AM, Mateusz Loskot <mateusz at loskot.net> wrote:
> Hi,
>
> Yet another curiosity from the OGC vs PostGIS ring.
> Given the WKT BNF grammars specified in the two versions of OGC SFS:
>
> 1) OGC 05-126 Version: 1.1.0
>
> <MultiPoint Tagged Text> := MULTIPOINT <Multipoint Text>
> <Multipoint Text> := EMPTY | ( <Point Text > {, <Point Text > }* )
> <Point Text> := EMPTY | ( <Point> )
> <Point> := <x> <y>
>
> 2) OGC 06-103 Version: 1.2.[0-1]
>
> <multipoint tagged text> ::= multipoint <multipoint text>
> <multipoint text> ::= <empty set>
>         | <left paren> <point text> {<comma> <point text>}* <right paren>
> <point text> ::= <empty set> | <left paren> <point> <right paren>
> <point> ::= <x> <y>
>
> Why PostGIS documentation shows MULTIPOINT(0 0,1 2)
> as example in "OpenGIS WKB and WKT"?
> (PostGIS can parse the degenerate form as well.)
>
> BTW, Wikipedia [1] also shows the same form (after PostGIS?):
> http://en.wikipedia.org/wiki/Well-known_text
>
> I sense, this is due to *incorrect* example presented in 6.2.3 section
> of the OGC 05-126 Version: 1.1.0,
> where ‘MULTIPOINT (10 10, 20 20)’ is presented.
>
> Which version of OGC SF does PostGIS implement here?
>
> Best regards,
> --
> Mateusz  Łoskot, http://mateusz.loskot.net
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