[postgis-users] postgis collect() issue

[strk at refractions.net]

collect() has changed in the 1.0 branch to never collapse
structures. You can try collecting underlying multigeoms
components, which should be done with something like:

	collect(geom(dump(input)))

--strk;

On Tue, Jul 11, 2006 at 11:53:12AM -0700, Zhiqiang Zhang wrote:
> The current postgis implementation of collect()
> doesn't seem to work with mapserver. I am using
> postgis 1.1.3, but actually the same happens to all
> other 1.0 versions as well. The following is a
> scenario:
> 
> Test SQL query (the_geom field is a MULTILINESTRING,
> default type used by shp2pgsql):
> 
> select collect(the_geom) as geom from roads where
> the_geom && setSRID('BOX3D(-121.934769
> 37.355285,-121.894769 37.395285)'::BOX3D, -1) group by
> name;
> 
> This query will return a GEOMETRYCOLLECTION of
> MULTILINESTRING as follows:
> 
> GEOMETRYCOLLECTION(MULTILINESTRING((-121.909167
> 37.35634,-121.911667
> 37.354041)),MULTILINESTRING((-121.901967
> 37.36404,-121.902167 37.36374)),...)
> 
> Mapserver won't be able to draw GEOMETRYCOLLECTION of
> MULTILINESTRING but only GEOMETRYCOLLECTION of
> LINESTRING. Applying the force_collection to the
> output geometry doesn't have any effect. I had a
> really old postgis prior to 0.9 the same query will
> properly return a GEOMETRYCOLLECTION of LINESTRING,
> which mapserver can draw. 
> 
> What is the solution for this? Is Mapserver still a
> good combination to use with postgis or not?
> 
>  
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> postgis-users at postgis.refractions.net
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