[Qgis-user] Extrange behaviour of clipping polygons in a shapefile

[Daniel Arribas-Bel]

Dear list,

I have found the following behaviour working with a polygon shapefile in
both qGIS 1.7-MacOS10.6.8 and 1.9master under Ubuntu12.04-64bit. It
originally happened with the 'Merge shapefiles into one' feature in vector
tools, but I've been able to recreate it by simply selecting a polygon and
use 'save selection as'. It does the clip just fine, but some of the fields
in the dbf are modified. As an example (which will illustrate is much
better than my words), I have uploaded an example shapefile 'ex.shp' on
this link <https://docs.google.com/open?id=0B9GhaNrWEIadUkFmREVxSnJRRW8>which
contains two polygons. If you select one of them and 'save selection
as', it creates a new shapefile (I'm attaching in the zip 'ex_cl.shp' for
one of the two). The field 'ALAND10' is modified and gives a negative
number when in origin it was positive.

Any clue about what is going on here? Am I missing something?

Thank you very much in advance,

]d[

-- 
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Daniel Arribas-Bel, PhD.
Url: darribas.org
Mail: darribas at asu.edu

GeoDa Center for Geospatial Analysis and Computation (geodacenter.asu.edu)
Arizona State University (USA)
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