[postgis-users] More details for errors

[Nicolas Ribot]

> Yes, it is 2.0
> http://postgis.refractions.net/documentation/manual-svn/ST_CollectionHomogenize.html
>
> Well, I am turning around the problem...
> I have to do a cast, as I used
> ST_Multi(ST_LineMerge(ST_Union(wkb_geometry)))::geometry(MultiLineString,xxx)
> in the first view to prevent errors of unconnected lines.
>
> Right now the best solution I have is to let the view being unusable, and
> another view to report errors.
> This is not very satisfying as if a problem occurs, I cannot use my view
> until I fix the geometric errors.
>
> Basically, I need to compute a view with a LineMerge returning LineString
> (i.e. leaving away features leading to MultiLineString) and another view
> returning IDs of features leading to MULTI.
>
> I thought about using ST_Touches but it only uses two geometries and I can
> have more in the LineMerge. No idea what to look for...
>
> Thanks for your help. I could go deeper in the problem!
>
> Greetings
>

I would then create 3 views:
One doing the actual computation (linemerge(Union)), then one view
where st_numgeometries(the_geom) = 1, and one view where
st_numgeometries(the_geom) > 1.

nicolas