[gdal-dev] Strange results of simple polygonising

[Casper Børgesen (CABO)]

Hi,

I have four simple rasters that I would like to polygonise:

1:
# # #
#    #
# #

2:
# #
#     #
# # #

3:
    # #
#     #
# # #

4:
# # #
#    #
   # #

It's the same shape, just rotated 90, 180, 270 degrees. The resulting polygons for 1 and 2 are simple polygons without holes, where the results for 3 and 4 are polygons with a hole intersecting the exterior ring. Thus 3 and 4 results in invalid geometries with self-intersection.

Is this the intended behavior of the polygoniser?


Regards, Casper
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