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

[Tom Jeffery]

Chaitanya,

I've found the issue with the particular shapefile I'm using.  It actually
has some null geometries in it, which are fixable using ESRI's "Repair
Geometry" tool.  I read that ogr2ogr is also suppose to remove records with
empty geometries, but it doesn't seem to be working on my file, even with
the -skipfailures flag set.

Any thoughts?  Or is there another good way to clean a shapefile that might
have null geometries?

Thanks so much for your help so far!

-Tom


Chaitanya kumar CH wrote:
> 
> Tom,
> 
> GDAL/OGR updates the shapefile along with the dbf file when a feature is
> changed. That means updating the extents according to the geometries in
> the
> changed features. My guess is that there is a problem reading a feature's
> geometry extents.
> 
> Call the OGRGeometry::getEnvelope method on each geometry and check if the
> OGREnvelope::MinX and OGREnvelope::MinY values are within the expected
> extents. You can isolate the problem this way.
> 
> Otherwise, put together a sample dataset and create a new ticket at
> http://trac.osgeo.org/gdal/newticket
> 
> On Wed, Aug 4, 2010 at 10:00 PM, Tom Jeffery <tjeffery at gmail.com> wrote:
> 
>>
>> Chaitanya,
>>
>> The updated file is read properly with ogrinfo.  The only difference
>> between
>> ogrinfo -al between the two, besides the new field that was created, is
>> the
>> extent, which looks like this:
>>
>> Original file:
>> Extent: (1528126.013001, 45899.818172) - (1542444.478012, 61468.662925)
>>
>> Updated file:
>>
>> (-179769313486231570000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.000000,
>>
>> -179769313486231570000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.000000)
>> - (1542444.478012, 61468.662925)
>>
>> That...is a really large negative number!  Any idea why it might be
>> getting
>> blown up?
>> -Tom
>>
>>
>> Chaitanya kumar CH wrote:
>> >
>> > Tom,
>> >
>> > Can you check the destination shapefile with 'ogrinfo' and see if it
>> > works?
>> > If ogrinfo gives a valid output of the new file, check with 'ogrinfo
>> -al'
>> > and compare it with the old file's output.
>> > ( http://www.gdal.org/ogrinfo.html )
>> >
>> > --
>> > Best regards,
>> > Chaitanya kumar CH.
>> > /tʃaɪθənjə/ /kʊmɑr/
>> > +91-9494447584
>> > 17.2416N 80.1426E
>> >
>> > _______________________________________________
>> > gdal-dev mailing list
>> > gdal-dev at lists.osgeo.org
>> > http://lists.osgeo.org/mailman/listinfo/gdal-dev
>> >
>>
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> 
> 
> 
> -- 
> Best regards,
> Chaitanya kumar CH.
> /tʃaɪθənjə/ /kʊmɑr/
> +91-9494447584
> 17.2416N 80.1426E
> 
> _______________________________________________
> gdal-dev mailing list
> gdal-dev at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/gdal-dev
> 

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