[R-sig-Geo] Linear interp irregular samples to irregular points

[Roger Bivand]

On Tue, 5 Jun 2007, Tim Keitt wrote:

> Anyone know of code that will do bilinear interpolation from irregular
> samples to another set of irregular locations (including points
> possibly outside the convex hull of the original points)? Akima
> interpolates to a regular grid AFAICT. I did find one package on CRAN
> that does this will splines, but I want something simpler. (The
> particular application requires many repeated calls.)

Would Tps() and predict() for Tps objects in fields meet your needs? I've 
used it for "faking" LOO CV to match spline interpolation to gstat.cv() in 
gstat, and it doesn't complain on many calls.

Roger

> 
> THK
> 
> 

-- 
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