[postgis-devel] force_collection()

[strk at refractions.net]

On Thu, May 19, 2005 at 11:21:36AM -0700, Paul Ramsey wrote:
> The semantics of force_collection are almost, but not quite, the same 
> between 0.9 and 1.0. The difference is causing mapserver breakage in 
> very rare cases (like the demo I am doing for MUM).
> 
> I think you will find that
> 
> asbinary(force_collection(collect(the_geom))) where the_geom is a 
> multilinestring returns a different result between 1.0 and 0.9
> 
> I do not know if we care enough to change it, but it is a backwards 
> compatibility thing for mapserver in rare cases.

I find the new behaviour more correct:
	collecting multilines produces a geometrycollection

The old behaviour was:
	collecting multilines produces a multilinestring

Old behaviour was also based on a limit of postgis: not being
able to nest geometrycollection. We can reproduce the old
behaviour by using dump() and collect() the multilines elements.

--strk;