[postgis-users] Trying to import natural earth data into

Brian Hamlin maplabs at light42.com
Thu Jan 6 22:51:53 PST 2011

regarding GRASS and PostGIS on Natural Earth vectors

   unfortunately, it seems that a v.in.ogr / v.out.ogr round trip
does *not* clean the vectors completely, as tested by st_isValid()

GRASS trunk (7)
PostGIS 1.5.3
current Natural Earth shp files,

tested table: 10m_urban_areas
12,022 polys

st_isValid() shows 31 errors
  self-intersection and ring self-intersection

PostGIS ST_Buffer(0) creates output
that is clean of these errors, according to PostGIS

GRASS 7 v.in.ogr / v.out.ogr creates output
that still has 14 polys with "ring self-intersection"
according to PostGIS

ps -
   this is true with or without benefit of the mighty "for" loop

best regards

Brian Hamlin
OSGeo California Chapter
(415) 717-4462 cell

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