[GRASS-stats] Spatial categories for risk data.
G. Allegri
giohappy at gmail.com
Thu Dec 10 11:38:46 EST 2009
Hi Arthur, this is the classical task of clustering/classification
algorithms (like SVM, k-means, etc.)
For R take a look at the Cluster task page [1] for unsupervised
classification, and Machine Learning [2] for some supervised methods.
In Grass the classification/clustering methods are mostly directed to
imagery data, and their objective is to classify spectral images [3]
[4]. Anyway you could use it with other kind of imagery...
You also could take a look to this Python/C project, quite easy to
use, for supervised clasification: https://mlpy.fbk.eu/
And LIBSVM, which has various interfaces (Python, R, etc.):
http://www.csie.ntu.edu.tw/~cjlin/libsvm/
Hope it helps,
giovanni
[1] http://cran.r-project.org/web/views/Cluster.html
[2] http://cran.r-project.org/web/views/MachineLearning.html
[3] http://grass.osgeo.org/grass64/manuals/html64_user/i.cluster.html
[4] http://grass.osgeo.org/grass64/manuals/html64_user/i.maxlik.html
Il 10 dicembre 2009 17.08, HINTERMEISTER, ARTHUR W. (Artie)
<AHINTERMEISTER at amica.com> ha scritto:
> Hello,
>
>
>
> I currently have a map that looks something like this:
>
>
>
> -----------------------------------------
>
> | x x o x o x |
>
> | x x x x a o a |
>
> | a x o o x |
>
> | x x o o o a |
>
> | x x x o a o a o|
>
> | x x o x o x a a a |
>
> | x x o o a a a |
>
> -----------------------------------------
>
>
>
> x = low risk
>
> o = moderate risk
>
> a = high risk
>
>
>
> Each letter represents a person, and the entire map represents a state. Each
> person’s “risk score” is a continuous numeric value, but I have categorized
> it into low, moderate, and high for visual simplicity. What I’m hoping to do
> is draw lines that will divide out the categories. The lines do not have to
> necessarily be straight, but I would like them to be simple enough. I figure
> that I would have to account for any overlapping or outlying persons. This
> is my initial idea of how the map would turn out:
>
>
>
> -----------------------------------------
>
> | / / |
>
> | / / |
>
> | x / o / a |
>
> | / / |
>
> | / / |
>
> | / / |
>
> | / / |
>
> -----------------------------------------
>
>
>
> I have downloaded and installed GRASS and R, but I am not sure what type of
> spatial method or analysis to use. Could someone please offer me advice on
> how to get started with this project? Thanks so much!
>
>
>
>
>
> ------------------------------------------------------
>
> Arthur Hintermeister
>
> ahintermeister at amica.com
>
>
>
>
>
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>
>
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