[postgis-users] quantiles, quartiles, or jenks natural
amitkulz at yahoo.com
Wed Mar 1 10:20:22 PST 2006
Sorry, I have been catching up on the past few months emails. I just
want to add that I read that quantiles and minimum boundary error are
better than jenks. Also minimum boundary error takes into account the
The two being better are mentioned in
Brewer, Cynthia A. & Pickle, Linda (2002) Evaluation of Methods for
Classifying Epidemiological Data on Choropleth Maps in Series.
Annals of the Association of American Geographers 92 (4), 662-681
And the minimum boundary algorithm is supposedly mentioned in
Cromley, E. K. , and R. G. Cromley. 1996. An analysis of alternative
classification schemes for medical atlas mapping. European Journal
of Cancer 32A (9): 1551 -- 59.
Cromley, R. G. , and R. D. Mrozinski. 1999. The classification of
ordinal data for choropleth mapping. The Cartographic Journal 36 (2):
101 -- 9.
Date: Tue, 14 Feb 2006 12:38:39 -0800
From: Paul Ramsey <pramsey at refractions.net>
I did some in PHP, but the algorithms are relatively braindead, the
quantile stuff in particular. Jenks I did some research on but never
really found a definitive description of the process. Some of the
descriptions ended up sounding like a k-means clustering idea, which
is not cheap!
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