[Qgis-user] Running v.clean on a QGIS vector layer (Polygon) through Sextante

[Victor Olaya]

Considering the comments in this thread, I think the best solution
would be to add more advanced parameters to allow more fine tuning for
users like you. That would include the option to perform several
cleaning operations at once, and also the option to select output
type. Since it is an advanced option, we can add that and then let
just advanced users hack on the GRASS commands.

Would that work for you? it doesn't look difficult to implement, and I
think it would be a good improvement.

Thanks!

Victor



2013/5/2 SBL <Stefan.Blumentrath at nina.no>:
> Hi
>
> Hope I am not too bothersome with that topic...
>
> Unfortunately, Sextante 1.09 was hidden in my OSGeo4W installation behind
> the old 1.07, so it took me a while to find the "advanced parameters".
> Actually, both Sextante versions were installed in parallel, which I was not
> aware of (neither the fact that allways only the old version was loaded).
>
> Now I reinstalled QGIS and QGIS-dev with Sextante 1.1, created a polygon
> layer with overlapping and not adjacent digitised boundaries (to be
> snapped), and ran some tests:
>
> Indeed, the advanced import parameters in Sextante 1.1 do the trick.
>
> However, I can confirm Bernds findings in that sense, that the advanced
> import parameters (especially snapping) in the v.in.ogr-part worked well,
> while using the default settings for v.in.ogr combined with snapping with
> exactly the same distance as in the earlier test in v.clean did not (though
> that is maybe a GRASS issue).
>
> Furthermore, different from what I and Paolo expected overlapping areas are
> beeing preserved in the Sextante output. I guess that is because Sextante
> uses "type=auto" in the v.out.ogr-part.
> Would it be possible to have "advanced parameters" also for exporting from
> GRASS, where for example selective export of geometry-types or layers could
> be choosen?
>
> Though it may be trivial to chain several v.clean steps in a Sextante model,
> this solution has definately some drawbacks. Because, as far as I can see
> from the log, there is allways export, location creation and import
> (including building of topology along with more or less cleaning) between
> two model-steps... This affects both behavior of a chain of v.clean-tools
> and performance...
>
> Cheers
> Stefan
>
>
>
> --
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