[postgis-users] multiline to linestring

Gustavo Ces g.ces at pettra.es
Wed Feb 6 02:58:23 PST 2008

Hi all,

       i´ve got a problem with ST_Dump() ( well, actually this one doesn´t exist )
and dump() function. I´m working with

"PostgreSQL 8.2.3 on i686-pc-mingw32, compiled by GCC gcc.exe (GCC) 3.4.2 (mingw-special)"
"POSTGIS="1.2.1" GEOS="2.2.3-CAPI-1.1.1" PROJ="Rel. 4.5.0, 22 Oct 2006" USE_STATS"

I want to convert linestrings from multilinestrings, with linemerge, to obtain united linestrings in overlapping points
with this sentence:

select dump(linemerge(collect(the_geom))) from lines

but i obtain:

ERROR: set-valued function called in context that cannot accept a set
Estado SQL:0A000

The result of:

select astext(LineMerge(Collect(the_geom))) from lines


"MULTILINESTRING((4.8938679245283 46.3443396226415,33.313679245283 73.7028301886792,49.5872641509434 80.0707547169811,90.9583136792453 89.2813679245283,54.3363797169811 103.03608490566,29.0620872641509 103.293985849057,12.2125589622641 107.1625,11.1624233831055 106.590266209164,10.4214805264064 107.529010012923,11.2220067193803 108.417488521584,12.2326314413493 107.778056025276),(37.506947728971 97.6302534161404,12.1756482134062 82.9892270906306))"

with numgeometries=2, the logic result with my original data.
How can i extract those linestrings separately?

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/postgis-users/attachments/20080206/f4ebbf34/attachment.html>

More information about the postgis-users mailing list