[Thuban-list] visual classifier

[Moritz Lennert]

Frank Koormann said:
> * Moritz Lennert <mlennert at club.worldonline.be> [031204 19:41]:
>> Daniel Calvelo said:
>>
>> >
>> > I also explored natural breaks. I found very scarce literature on the
>> > subject.
>> >>From what I gathered, natural breaks are based on a kernel
>> approximation
>> >> to
>> > the data distribution. From previous experience, programming these
>> things
>> > needs tuning and lots of special casing. If you have ideas on the
>> subject,
>> > they are most welcome.
>> >
>>
>> We have a fortran program here which was written ages ago and which uses
>> a
>> geometrical approach, exploring the slope between data points. If you
>> are
>> interested I can send it to you (I will have to check with the authors,
>> but I would be very surprised if they weren't willing to release the
>> code
>> freely).
>
> Just for completeness or if some problems arise from using the fortran
> code: The original paper on natural breaks ("Jenks
> optimization") is "Error on Choroplethic Maps: Definitions,
> Measurement, Reduction", G. F. Jenks & F. C. Caspall, Annals of the
> Association of American Geographers 61 (2), pp. 217-244 (1971)
>
> Should be available via JSTOR
> (http://www.jstor.org/journals/00045608.html)
> if somebody has an account there.
>

I do and I downloaded the article if anyone is interested.

Moritz