Geometry Boost List: Re: [geometry] Changes in WKB (read) behaviour proposal (WKT Part)

Subject: Re: [geometry] Changes in WKB (read) behaviour proposal (WKT Part)
From: Mateusz Loskot (mateusz_at_[hidden])
Date: 2013-11-04 17:05:04

On 4 November 2013 21:11, Barend Gehrels <barend_at_[hidden]> wrote:
> Mats Taraldsvik wrote On 4-11-2013 21:31:
>>>
>>>> The parser should support 3D as long as both the expected point
>>>> dimensions
>>>> and the wkb point dimensions match. I have tested this for 3D/Z. M is
>>>> not supported by WKT yet, apparently, so I could not test this easily.
>>>
>>> M is there too, see OGC specification in version 1.2.0.
>>
>>
>> I meant boost::geometry's WKT reading. At least, I got an error when I
>> tried POINTM(1 2 3), but that might be the wrong syntax.
>
>
> POINT  M ( 1 2)
> is OK and according to the spec.
> http://en.wikipedia.org/wiki/Well-known_text

Barend,

Are you sure this is a valid POINT M?

The BNF include in the OGC SFS spec is clear the "third value" for M
is required:

<point z>  ::= <x> <y> <z>
<point m>  ::= <x> <y> <m>
<point zm> ::= <x> <y> <z> <m>

> Not all of WKT is supported, for example: TIN/TRIANGLE are not. But the
> specs is followed quite closely.

Yes.

> We also have additions: we use WKT for the unit-test too, extensively.
> Therefore we also added BOX and SEGMENT. We also support e.g. 5D (e.g. for
> distance centroid) and therefore our wkt's can have 2,3,4,5 or more
> dimensions

Right, but IMHO those WKTs for tests are sort of Boost.Geometry Extended WKT :)

Best regards,
-- 
Mateusz  Loskot, http://mateusz.loskot.net