[Qgis-developer] Re: [GRASS-user] weird dbf file in GRASS 6.4

[Maciej Sieczka]

QGIS and GRASS devs,

Below I'm forwarding you a QGIS-GRASS issue. It seems to be somewhat
related to https://trac.osgeo.org/qgis/ticket/554#comment:7.

maning sambale pisze:

> I am editing a dbf file of a GRASS vector in QGIS.  When I launch the
> open attribute table in QGIS it shows a long table of over a thousand
> records, but when I open the file in OpenOffice Calc 3.0 it only shows
> me 30 records which was the  30 classes I initially converted from
> raster to vector.
> 
> Using:
> 
> r.to.vect -v input=x output=x_vect feature=area --overwrite --verbose
> 
> My plan is to edit the class categoris of each vector polygon in
> OOCalc.  Any ideas why is it like this?  I don't have problems with my
> previous vector files when I am using 6.3

You used the '-v' switch which means: "Use raster values as categories
instead of unique sequence". Thus, it is normal that the output table
has only that many rows, as many unique cell values were there in the
input raster map. Multiple polygons are linked to the same table row (by
having the same category), so there are more polygons than rows in the
table indeed.

QGIS table editor does not present a GRASS vector map table as it really
is, but treats each vector feature separately. This has the pro that you
can access individual polygons from the table editor, no matter that
multiple polygons have the same category. The con is that it's not the
real table as it is, which confuses some users. Best if QGIS could
provide both modes, with the current behaviour as an option and
defaulting to real table layout.

Maciek

-- 
Maciej Sieczka
www.sieczka.org