[postgis-users] polygonize line strings

Bart van den Eijnden (OSGIS) bartvde at xs4all.nl
Fri Mar 3 00:58:30 PST 2006

Hi list,

I have a dataset in the form of a linestring shapefile, it is in fact a 
cadastral map. This shapefile consists of many separate linestrings per 
polygon, and has an attribute stating the cadastral object to the left 
of the linestring (PERCEEL_LI), and another one describing the cadastral 
object right of the linestring (PERCEEL_RE). I also have available a 
points shapefile which has the cadastrale object code as well.

Can this data be polygonized with PostGIS? If so how can this be done?

I am assuming the linestrings first need to be merged somehow in order 
for the polygonize function to work properly. But the problem is 
sometimes the cadastral object code is in the PERCEEL_RE attribute, and 
sometimes in PERCEEL_LI ofcourse (which the images also illustrate), so 
there is not a single attribute that can serve for the merging.

I have put up 2 images illustrating the problem on my website:


Thanks in advance.

Best regards,

Bart van den Eijnden
OSGIS, Open Source GIS

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