[geos-devel] Polygonizer returns inner rings on their own?

[Frederik Ramm]

Hi,

    why is it that the (C++) Polygonizer, when given the following four 
geometries,

         "LINESTRING(1 1, 1 10, 10 10)"
         "LINESTRING(10 10, 10 1, 1 1)"
         "LINESTRING(20 20, 20 30, 30 30, 30 20, 20 20)"
         "LINESTRING(3 3, 3 4, 4 4, 4 3, 3 3)"

(1 and 2 together form a shell, 3 forms a disjunct shell, 4 forms an 
inner ring of 1+2)

returns a collection of three polygons:

POLYGON ((1.00 1.00, 1.00 10.00, 10.00 10.00, 10.00 1.00, 1.00 1.00), 
(3.00 3.00, 4.00 3.00, 4.00 4.00, 3.00 4.00, 3.00 3.00))
POLYGON ((20.00 20.00, 20.00 30.00, 30.00 30.00, 30.00 20.00, 20.00 20.00))
POLYGON ((3.00 3.00, 3.00 4.00, 4.00 4.00, 4.00 3.00, 3.00 3.00))

I'm ok with the first and second, but the third one has already been 
used as a "hole" inside the first and should not be returned again - or 
is there a misunderstanding on my part?

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"