[Qgis-user] Trouble with overlay in 1.8.0

[Roxette]

I am having a similar problem having upgraded from 1.7.4 to 1.8 -
specifically, using fTools to do an intersection between two point datasets
(where the points in each dataset are exactly co-located) creates an empty
shapefile with all the attributes of the two datasets, but no entries. The
SEXTANTE tools, however, seem to work fine?

I have tried the operations on both Mac OSX 10.6.8 and Scientific Linux 6.2
and both are giving exactly the same error for the same data.

Cheers,
Roxette


Havard Tveite wrote
> 
> I have done some more testing and searching.
> 
> For very simple datasets, it seems that most overlay
> operations work.  The exception is for point datasets.
> I found Bug #5861 (Vector menu and Sextante -> ftools
> behaving inconsistently) that seems related.
> 
> However, with some more complex datasets, I get problems
> with some line-polygon intersects and polygon-polygon
> unions.
> 
> Håvard
> 
> On 8/29/2012 10:39 AM, Havard Tveite wrote:
>> After moving to QGIS version 1.8.0 (from 1.7.4), I am having
>> trouble with overlay (intersection, union).
>> The intersect function (Vector-> Geoprocessing Tools-> Intersect)
>> gives the following warning:
>>
>> * Warnings:
>> * Feature geometry error: One or more output features ignored due to
>> invalid geometry.
>> * Some output geometries may be missing or invalid.
>>
>> The resulting dataset contains no elements (but has all
>> the attributes from the datasets used in the operation).
>> I have tested with some "normal" and some very simple datasets
>> (point dataset with one point and a polygon dataset with one
>> polygon), and observe the same behaviour for all the cases.
>> I have only tested with Shapefile datasets.
>>
>> I have done most of the testing on Windows XP, but also some
>> testing on Ubuntu 12.04.
>>
>> union seems to have the same problems as intersection.
>>
>> I had no problems with intersection in 1.7.4.
>>
>>
>> Håvard Tveite
> 
> -- 
> Håvard Tveite
> Department of Mathematical Sciences and Technology, UMB
> Drøbakveien 31, POBox 5003, N-1432 Ås, NORWAY
> Phone: +47 64965483 Fax: +47 64965401 http://www.umb.no/imt/
> _______________________________________________
> Qgis-user mailing list
> Qgis-user at .osgeo
> http://lists.osgeo.org/mailman/listinfo/qgis-user
> 




--
View this message in context: http://osgeo-org.1560.n6.nabble.com/Trouble-with-overlay-in-1-8-0-tp4998524p4998847.html
Sent from the Quantum GIS - User mailing list archive at Nabble.com.