[GRASSLIST:9082] Re: Global interpolation: trend

[Carlos "Guâno" Grohmann]

You can also use R satistical language, to fit a trend surface up to 6th order.

check out this paper:

GROHMANN, C. H., 2005. Trend-surfaces analysis of morphometric
parameters: A case study in southeastern Brazil.
Computers & Geosciences, 30 (8):1005-1014.

grabe it here: http://www.igc.usp.br/pessoais/guano/downloads/Grohmann_CAGEO_2005.pdf


cheers

Carlos


On 11/15/05, Roger Bivand <Roger.Bivand at nhh.no> wrote:
> On Tue, 15 Nov 2005, Wolf Bergenheim wrote:
>
> > Hi!
> >
> > Is it possible to do an interpolation of points to a surface by fitting
> > the points to a first or second degree equation with GRASS or any other
> > program?
> >
>
> You can use gstat with GRASS to fit a trend surface to points and predict
> a surface, see Neteler and Mitasova (2nd edition) Open Source GIS: A
> GRASS GIS Approach, pp. 328-333 for GRASS 5, and notes on
> http://www.gstat.org/grass.html for GRASS 6. You will find that the d=
> argument sets the trend order degree.
>
> > --W
> >
>
> --
> Roger Bivand
> Economic Geography Section, Department of Economics, Norwegian School of
> Economics and Business Administration, Helleveien 30, N-5045 Bergen,
> Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
> e-mail: Roger.Bivand at nhh.no
>
>


--
+-----------------------------------------------------------+
              Carlos Henrique Grohmann - Guano
  Geologist M.Sc  - Doctorate Student at IGc-USP - Brazil
Linux User #89721  - carlos dot grohmann at gmail dot com
+-----------------------------------------------------------+
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