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

[Paul Ramsey]

Not the first to notice this, though apparently it's rare enough to
only be found spottily.

http://lists.osgeo.org/pipermail/postgis-devel/2011-February/011759.html

The fact that the postgis form is in other places (openlayers) makes
things harder yet.

And the root cause raises his voice here,
http://lists.osgeo.org/pipermail/postgis-users/2003-September/003168.html

P


On Wed, Dec 4, 2013 at 7:44 AM, Paul Ramsey <pramsey at cleverelephant.ca> wrote:
> 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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