postgis geometrycollection in mapserver

Akio Takubo takubo at SARUGA-TONDARA.NET
Mon Dec 4 09:42:54 EST 2006


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 <ale.pas at TISCALI.IT> 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
> 



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