Hi Milton thanks for your help I want to compute a lot of things.. :) for instance, I want to look at the large scale (regional, non-local) behavior of slope and aspect, but since aspect is a circular variable, I can't just go around with mean/median/etc, which are the tools I have on GIS, so I was hoping I could find some way to define the moving-window and the apply some function (from a package or user-defined) to the values within the window (like circular statistics). best regards Carlos (Brazil / UK)
On 7/1/07, Milton Cezar Ribeiro <milton_ruser at yahoo.com.br> wrote:
Hi Carlos,
What are really you looking for? What you want to compute for the central
pixel?
I use FRAGSTATS to compute some landscape metrics using moving windows.
There you can define circular and rectangular shaped search windows, sized
as you want.
Kind regards,
Miltinho
Brazil
----- Mensagem original ----
De: "Carlos "Gu?no" Grohmann" <carlos.grohmann at gmail.com>
Para: r-help at stat.math.ethz.ch
Enviadas: Quarta-feira, 27 de Junho de 2007 12:27:28
Assunto: [R] moving-window (neighborhood) analysis
Hello all
I was wondering what would be the best way to do a moving-window
analysis of a matrix? By moving-window I mean that kind of analysis
common in GIS, where each pixel (matrix element) of the resulting map
is a function of it neighbors, and the neighborhood is a square
matrix.
I was hoping there was some function in R that could do that, where I
could define the size of the neighborhood, and then apply some
function to the values, some function I don't have in GIS packages
(like circular statistics).
thanks all.
Carlos
--
+-----------------------------------------------------------+
Carlos Henrique Grohmann - Guano
Visiting Researcher at Kingston University London - UK
Geologist M.Sc - Doctorate Student at IGc-USP - Brazil
Linux User #89721 - carlos dot grohmann at gmail dot com
+-----------------------------------------------------------+
_________________ "Good morning, doctors. I have taken the liberty of removing Windows 95 from my hard drive." --The winning entry in a "What were HAL's first words" contest judged by 2001: A SPACE ODYSSEY creator Arthur C. Clarke ______________________________________________ R-help at stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. ________________________________ Novo Yahoo! Cad?? - Experimente uma nova busca.
+-----------------------------------------------------------+
Carlos Henrique Grohmann - Guano
Visiting Researcher at Kingston University London - UK
Geologist M.Sc - Doctorate Student at IGc-USP - Brazil
Linux User #89721 - carlos dot grohmann at gmail dot com
+-----------------------------------------------------------+
_________________
"Good morning, doctors. I have taken the liberty of removing Windows
95 from my hard drive."
--The winning entry in a "What were HAL's first words" contest judged
by 2001: A SPACE ODYSSEY creator Arthur C. Clarke