[postgis-users] LINEMERGE 4d Geometry Bug?

[strk at refractions.net]

LineMerge is a GEOS-implemented feature, and as such discards the
M values. Having them copied to Z is a bug, altought it might sounds
a useful one, doesn't it ?

--strk;

On Fri, Jun 02, 2006 at 10:32:57AM +0100, Düster Horst wrote:
> I'm playing with the PostGIS linear referencing functions. To create a route
> system I collect all measured linestrings with respect to their ascending M
> measures. As the result I get a geometrycollection for every route. To merge
> the single linestrings of the geometrycollection to one linestring I use the
> function linemerge. At this point I'm in doubt about a bug of the function
> linemerge.
> 
> After merging the geometrycollection to my expected linestring all measures
> where copied to the Z dimension and the M dimension does no longer exist. 
> 
> I'm in doubt about if this is the intended result??
> 
> With best regards,
>  
> Dr. Horst Düster 
> GIS-Koordinator, Stv. Amtschef
> 
> Kanton Solothurn 
> Amt für Geoinformation
> Abteilung SO!GIS® Koordination
> Rötistrasse 4
> CH-4501 Solothurn 
> 
> Tel.: ++41 (0)32 627 25 32 
> Fax: ++41 (0)32 627 22 14
> 
> horst.duester at bd.so.ch 
> www.sogis.so.ch