[postgis-devel] OGC polygon constructors (was: PostGIS 1.1.0 - call for closeup)

[strk at refractions.net]

On Fri, Dec 09, 2005 at 04:23:59PM +0100, strk at refractions.net wrote:
...
> Nonetheless, many items in the TODO list are completely missed:
...
> - OGC polygon constructors

I'm approaching this. SFSQL 1.1 contains the following information
about these:

>  As an optional feature, an implementation may also support `building' of
>  Polygon or MultiPolygon values given an arbitrary collection of possibly
>  intersecting rings or closed LineString values.  Implementations that
>  support this feature should include the following functions:
> 
>  BdPolyFromText(multiLineStringTaggedText String, SRID Integer): Polygon
> 
>    Construct a Polygon given an arbitrary
>    collection of closed linestrings as a
>    MultiLineString text representation.
> 
>  BdMPolyFromText(multiLineStringTaggedText String, SRID Integer): MultiPolygon
> 
>    Construct a MultiPolygon given an
>    arbitrary collection of closed linestrings as a
>    MultiLineString text representation.

Given these specs I think we can avoid use of GEOS for the construction,
as the only required thing is to find out what is an hole and
what is a shell. C code for this is already present in the loader.

The alternative would be using just a comple of wrappers
to the polygonize_garray() function.

Thoughts ?

--strk;

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