Tom,
so far as I am aware, neither GDAL/OGR nor ArcGIS update a shapefile in situ
- I believe that ArcGIS creates a temporary dataset, performs the update as it
copies the input data over, then deletes and renames to get the replacement. I
have used a similar method with Shapelib over the years and have done so with
OGR more recently. I think it likely that attempting to update a shapefile
structure in situ is going always to carry the risk of corruption ...
Best wishes,
Peter
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
Tom,
The -skipfailures flag skips only failures to create new features. Null
geometries in non-null shapetype shapefile are not handled.
The only way I can think of to clean such a file is by checking the geometry
in each feature.
On Thu, Aug 5, 2010 at 1:01 AM, Tom Jeffery <[email protected]> wrote:
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
--
--------------------------------------------------------------------------------
Peter J Halls, GIS Advisor, University of York
Telephone: 01904 433806 Fax: 01904 433740
Snail mail: IT Services, University of York, Heslington, York YO10 5DD
This message has the status of a private and personal communication
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