[gdal-dev] Re: Editing attributes with ogr causing corrupt shapefile

[Frank Warmerdam]

Tom Jeffery wrote:
> Chaitanya,
> 
> I wrote up a method to find and delete geometries that fall outside of the
> reported Extent from the shapefile.  It seems to be doing the trick, though
> with some strange side effects.  
> 
> It finds the bad features properly, and I remove them with
> layer.DeleteFeature(feature.GetFID()), but the .shp part of the shapefile is
> never updated.  (The dbf is the only file to change.)  Everything looks fine
> in OGR and ArcGIS, but if I run repair geometry in ArcGIS on the same file,
> it deletes the "same" records, causing the file to become completely
> unreadable.
> 
> I seem to recall reading about this before, but haven't turned up anything
> in google searches.  Is there a method to properly delete a record so the
> .shp is updated as well?

Tom,

I believe OGR takes the approach of marking shapes deleted by setting the
deleted flag in the .dbf file.  As far as I knew, this is a reasonable
approach as far as ArcGIS is concerned.  I don't know why ArcGIS does
something that corrupts the file.  If you figure out the issue let us know.

In the meantime, after doing the cleanup operation you can run ogr2ogr on
the file to create a new file with all deleted records/shapes discarded.

eg.
ogr2ogr out.shp in.shp

Best regards,
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