[Qgis-user] split point cloud into X randomly selected (equally sized) parts

[Victor Olaya]

Olav,

You've probably solved your problem already, but you might like to
have a look at this post I wrote about how to do that in several ways
using SEXTANTE for QGIS

http://qgissextante.blogspot.fr/2012/11/spliting-vector-layer.html

Thanks for the idea for the post :-)

Victor


2012/11/20 Paulo van Breugel <p.vanbreugel at gmail.com>:
> Have a look at the v.kcv function in GRASS GIS
> (http://wgbis.ces.iisc.ernet.in/grass/gdp/html_grass64/v.kcv.html). This
> function randomly partition points into test/train sets.
>
>
>
> On 11/19/2012 12:40 PM, Olav Peeters wrote:
>
> Hi everyone,
> for the purpose of speeding up a complex interpolation (written in single
> core Fortran-code) we would want to split a cloud of points (ca. 3 million
> irregular points) into X number of parts (eg 20 parts of more or less 150
> 000 points). Does anyone know of some QGIS-extension that could do this kind
> of a job?
>
> I was looking at a Saga-gis module ("Shapes - Tools > Split Shapes Layer
> Randomly") in the SEXTANTE toolbox. This is perfect if you want to split
> shapes into two parts with varying proportions between the two parts. I can
> perform this sequentially to arrive at the desired number of parts, but is
> very time consuming if you want to compare the impact on the system of
> splitting everything in eg 20 parts versus 15 or 12 or..
>
> Preferably, a solution should be executable from the command-line.
>
> Cheers,
> Olav
>
>
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