[GRASSLIST:9078] Re: Global interpolation: trend

[Roger Bivand]

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