Opened 11 years ago

Closed 8 years ago

#4471 closed defect (invalid)

ogr2ogr with the simplify switch does not preserve previously coincident boundaries

Reported by: bsh Owned by: warmerdam
Priority: normal Milestone:
Component: default Version: unspecified
Severity: normal Keywords:
Cc:

Description

i have been converting a shp file to oracle spatial format using ogr2ogr with the simplify switch. while simplify works nicely and self-intersections appear minimal, there are gaps/overlaps between shared boundaries which i wasn't expecting bearing in mind the documentation says it preserves topology. is the command i am using correct and should i expect it to preserve previously coincident boundaries?

the command i am using is:

ogr2ogr -f OCI OCI:uk_atlas/uk_atlas@ C:\Projects\Customer\Ess\Census\Load\Data\Geography2\GOR_APR_2001_EN_BGC.shp -simplify 1000 -nln GOR_SMP -lco SRID=81989 -lco LAUNDER=YES -lco DIM=2 -lco GEOMETRY_NAME=GEOM -lco INDEX_PARAMETERS=TABLESPACE=UK_ATLAS

Change History (3)

comment:1 by Even Rouault, 11 years ago

The simplification is done on each feature geometry, not globally on the layer, so the result you observe is expected. This should be the same results as running as "SELECT ST_SimplifyPreserveTopology(geom) FROM xxxx" in a PostGIS DB. See http://postgis.org/documentation/manual-svn/ST_SimplifyPreserveTopology.html

comment:2 by Jukka Rahkonen, 9 years ago

Behaviour is also mentioned in ogr2ogr documentation http://gdal.org/ogr2ogr.html -> Close ticket as Won't fix.

comment:3 by Jukka Rahkonen, 8 years ago

Resolution: invalid
Status: newclosed

Behaviour is expected. Closing as invalid.

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