[GRASS-dev] library of data partitioning algorithms

[Roger Bivand]

On Mon, 27 Nov 2006, Moritz Lennert wrote:

> Hello,
> 
> In the effort of creating a C-version of d.vect.thematic we are planning 
> on using a series of library functions for data partitioning which would 
> contain classical algorithms such as equal interval, quantiles, stdev, 
> etc, but also more sophisticated ones such as "natural breaks" or 
> kmeans. They would take a vector of data and the number of desired 
> classes and return the breakpoints.
> 
> These functions could then be used by other modules, such as d.vect.chart.
> 
> I have two questions concerning this:
> 
> 1) Where should we integrate these functions ? lib/stats is currently 
> limited to raster, should we integrate non-raster functionality in there ?
> 
> 2) Does anyone know of an existing C-library of such functions. Just so 
> that we don't reinvent the wheel.

You'll find some references in the R classInt package on CRAN, including 
the Fortran for Fisher-Jenks (not C). There is a good deal of C code in R 
itself, some from statlib.

Roger

> 
> Thanks,
> 
> Moritz
> 
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-- 
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: Roger.Bivand at nhh.no