you can always break up the geometry collection into individuals geometries
like so...
create or replace function breakup (geometry) returns void as $$
declare
geom geometry;
begin
for i in 1..NumGeometries($1) loop
geom := GeometryN($1, i);
// add to new table
end loop;
return;
end;
$$ language plpgsql;
you can also write a PL/PGSQL function that returns a set of geometries from
the geometrycollection, like this...
create or replace function foobar (geometry) returns setof geometry as $$
declare
geom geometry;
begin
for i in 1..NumGeometries($1) loop
return next GeometryN($1, i);
end loop;
return;
end;
$$ language plpgsql;
the call like this...
select * from foobar(Collect(GeomFromText('POINT(1
1)'),GeomFromText('POINT(1 2)')));
of course a wrapper function could be used to iterate over all geoms in a
table, all geoms in a bbox, etc.
On 12/4/06, Akio Takubo <[EMAIL PROTECTED]> wrote:
Hello Alessandro,
I'm also trying to use a geometry collection column
with PostGIS layer just now. It is a interesting topic for me.
Does anyone have a nice experience with Geometry Collection
column?
As far as I know, Mapserver and other some applications
do not support Geometry collection column perfectly.
In Mapserver, as I tested some cases and saw mappostgis.c,
each layer type works following.
* POINT shows point and all nodes of linestring and polygon
if there is no nested geometry collction.
* LINE shows all linestrings and polygons
If there are point or geometry collection, it does not work correctly
* POLYGON shows all polygons.
If three are other types of geometry, it does not work collectly.
Totally, now it is no consideration of mixed geometry types or
includes nested geometry collction in PostGIS.
Is it a bug or specification for no consideration for these geometry
at force_to_~ functions in mappostgis.c?
And Mapserver uses force_collection function for fetching geometry,
but force_collection does not extract a nested geometry collection.
I think it is better force_collection (or other new function)
works all nested geometry collection (and multi~ types).
Best regards,
Akio Takubo
On Mon, 4 Dec 2006 11:15:12 +0100
Alessandro Pasotti <[EMAIL PROTECTED]> wrote:
> Hello,
>
> I have a layer where the_geom is a geometrycollection (of linestrings),
is it
> possible to show it in mapserver 4.10?
>
> What "type" (POINT, POLYGON or whatever) should I set?
>
> --
> Alessandro Pasotti
> itOpen - "Open Solutions for the Net Age"
> w3: www.itopen.it
> Linux User# 167502
>
--
Regards,
Mark Thomas
[EMAIL PROTECTED]
205.529.9013
"Commit to the Lord whatever you do,
and your plans will succeed." - Proverbs 16:3
