SHANNON INDEX AND MUCH MORE

giovanna ranci at quercia.elet.polimi.it
Tue Oct 1 08:00:00 EDT 1996

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Good day to everybody,
I am an Enviromental Engineering student and I am working with Grassland
for my thesis. My aim is to use Grassland to build Habitat

Suitability Maps and to create (using Tcl/Tk) an user-friendly interface for
people (as biologists) interested in creating Habitat

Suitability Indexes but without GIS experience.
Actually I have two problems and I would be happy if somebody can help me.

1)  I need to calculate SHANNON DIVERSITY INDEX which is defined as:
H=-summation(pi*ln pi)  ;
i=1,2,...,n  ;
n=number of categories ;
pi=number of category i cells / number of cells in the neighborhood
(ex: 9 if we  consider 3*3 neighborhood).
This index infact is not calculated by r.neighbors function. IF  at least
r.neighbors function calculates the number of cells which have

category i in the neighbohood, then Shannon diversity index could be
calculated easily with r.mapcalc. Anyway this possibility does

not exist.

2) I would need to create a raster map where each cell has the value of the
AREA of the clump which it belongs to, and another where

the value of each cell is the PERIMETER of the clump. I did not succed in
doing that.

3)  How can I import maps whose projection is Gauss-Boaga?

Did anybody develop GRASS functions which can be useful for my purposes?
How can I import them in Grassland?
ANY help is welcomed, thanks.

I am also desperately looking for Grass Tutorials about functions r.binfer
(this is the most important to me), r.mapcalc, r.cost, r.combine, r.infer,
r.neighbors.
Could you help me?

Thank you very much,
Regards

Giovanna Ranci Ortigosa
student of Enviromental Engineering
Politecnico di Milano, Italy
e-mail: ranci at quercia.elet.polimi.it

Giovanna Ranci Ortigosa
student of Enviromental Engineering
Politecnico di Milano
Italy

e_mail: ranci at quercia.elet.polimi.it

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