Hello all.
I need to do some statistical analysis of some morphological map I produced,
so I installed R and GRASS-R interface.
What I need should be simple: for each map (about six maps), I want general
stats (mean, quartiles, variance...), histogram, and them compare maps two
at a time with scatter plots and linear regression.
the problem is that I'm lost with R.
Does anyone know a simple tutorial, a step-by-step kind of thing, explanning
how to get the data from grass and them use it into R?
thanks in advance
+-------------------------------------------------+
Carlos Henrique Grohmann de Carvalho - Guano
Geologist - MSc Student at IGc-USP - Brazil
Linux User #89721 PGP key: www.keyserver.net
+-------------------------------------------------+
On Tue, 25 Feb 2003, Carlos Henrique Grohmann de Carvalho wrote:
Hello all.
I need to do some statistical analysis of some morphological map I produced,
so I installed R and GRASS-R interface.
What I need should be simple: for each map (about six maps), I want general
stats (mean, quartiles, variance...), histogram, and them compare maps two
at a time with scatter plots and linear regression.
the problem is that I'm lost with R.
Does anyone know a simple tutorial, a step-by-step kind of thing, explanning
how to get the data from grass and them use it into R?
A gentle guide for R itself from http://cran.r-project.org/other-docs.html
is: "A Guide for the Unwilling S User" by Patrick Burns, where S is a
general name for R or S-PLUS. There are plenty of others there. For
getting the raster layers from GRASS to R, please see the help page of the
interface function rast.get() - type help(rast.get) at the R prompt after
loading the library with library(GRASS). There are plenty of examples on:
http://grass.itc.it/statsgrass/grass_r_interface.html, and on its link to
"Learning R".
Good luck!
Roger
--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: Roger.Bivand@nhh.no
On Tuesday 25 February 2003 07:17, Carlos Henrique Grohmann de Carvalho wrote:
Hello all.
I need to do some statistical analysis of some morphological map I
produced, so I installed R and GRASS-R interface.
What I need should be simple: for each map (about six maps), I want general
stats (mean, quartiles, variance...), histogram, and them compare maps two
at a time with scatter plots and linear regression.
the problem is that I'm lost with R.
Does anyone know a simple tutorial, a step-by-step kind of thing,
explanning how to get the data from grass and them use it into R?
There are several sources for information on R. Most information on S+ for
instance will be pertinent. Two published sources respecting R are An
Introduction to R by Venables, Smith and the R Development Team. Another is
Introductory Statistics with R by Dalgaard. There is also some extensive
discussion in Open Source GIS: A GRASS GIS Approach by Marcus Neteler and
Helena Mitasova.
John Dougherty