Kedar, If you build GDAL/OGR without use of the GEOS library then I believe the spatial filtering is normally just based on bounding boxes. So you are likely getting back all the zip codes which have a bounding box including the target point.
The SetSpatialFilter() method should have documentation suggesting in some scenarios it may produce more features than strictly satisfy the spatial filter. If you rebuild with GEOS you will hopefully get an exact spatial filtering. Some caveats might apply for points on zip code boundaries. Of course it is also possible there is some overlap in your zip code polygon set. One thing I'm learning in my current job is that datasets are rarely clean. :-) Best regards, Frank On Fri, Jun 8, 2012 at 12:59 PM, Kedar Deshpande <[email protected]> wrote: >> Hi, >> >> I am creating an application that reads a shapefile having Zipcode >> Tabulation Area information (provided by US Census Bureau). >> Once I get the layer, I am setting a spatial filter on it. I am passing a >> OGRPoint object to it having some values for latitude and longitude. >> After I apply this filter, I am iterating over the Features that the layer >> returns. >> But for a given geometry point, it is returning more than one features. I >> am extracting the zipcode from the feature. >> So, it is returning me more than one zip codes for one lat/long point. >> Could someone please let me know why is this behavior observed ? >> If it returns multiple features for a filter, what is the order in which >> it returns the features (when we call layer->GetNextFeature()). >> Is this order according to how exactly the filter matches Or is it not >> definite ? The documentation in the API does not mention about the order. >> >> Thanks, >> Kedar > > > > _______________________________________________ > gdal-dev mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/gdal-dev -- ---------------------------------------+-------------------------------------- I set the clouds in motion - turn up | Frank Warmerdam, [email protected] light and sound - activate the windows | http://pobox.com/~warmerdam and watch the world go round - Rush | Geospatial Software Developer _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
