[FWTools] OGR2OGR MULTIPOLYGON verses outer and inner rings

Frank Warmerdam warmerdam at pobox.com
Mon Jan 7 13:01:02 EST 2008

David R Robison wrote:
> The data has been provided to me in a Personal Geo Database. I am 
> processing it and loading it into a PostGIS database. Thanks, David


Interesting.  There was a bunch of work done for GDAL/OGR 1.5.0 in the
shapefile driver to better categorize rings in polygons and multipolygons.
The personal geodatabase driver uses essentially the same disk format
but may lack some of the logic in the shapefile driver.  I believe the
special logic in GDAL/OGR 1.5 was based on having GEOS built in.

If you can easily do so, you might want to dump the personal geodatabase
to shapefile(s) with either ArcGIS or even perhaps ogr2ogr, and then
read back from that to see if the geometries are correctly interpreted.

Best regards,

> Frank Warmerdam wrote:
>> David R Robison wrote:
>>> I am trying ti load data provided to me into PostGIS using OGR2OGR. 
>>> The layer is a MULTIPOLYGON. However, when I import it into PostGIS, 
>>> the multiple polygons are collapsed into one polygon with multiple 
>>> inner rings. Is there some way to tell OGR2OGR that there are no 
>>> inner rings and that every thing is an outer ring?
>> David,
>> What is the input format?  There is no way currently for ogr2ogr to
>> reinterprete geometries in the way you want, though something could be
>> scripted.  But I wonder if it would be better to fix the input driver.
>> Best regards,

I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | President OSGeo, http://osgeo.org

More information about the FWTools mailing list