[R] Z aware interpolation

David Richard John Pleydell D.R.J.Pleydell at pgr.salford.ac.uk
Mon Sep 22 15:03:54 CEST 2003

Hi Monica

geoR enables you to do universal kriging, kriging where the mean is 
modelled on one or more Z variables, you can do this by specifying the 
trend component (your Z variable) with the likfit function (if you are 
using maximum liklihood based methods), or with variog function which is 
used with variofit for least squares based methods.

As Edzer pointed out there is also gstat, you may like to look at 
co-kriging which enables spatial information in your Z variable to be 
included in you interpolation. With co-kriging you end up using 3 variogram 
models compared to 1 used in universal kriging, but it may (or may not) 
give a more meaningful prediction depending on your problem.

Then with some cunning wizardry and a little luck you can then export to 
your GIS package.

Hope this helps

>Hello again,
>There is any package which does Z aware (real 3D) interpolations?
>It can be any method (IDW, kriging or spline) but it should take into
>consideration not only x and y coordinates for interpolation, but
>also z coordinate. I looked into different packages but it seems i
>didn't find the right one.
>The ultimate goal is to import the output into a GIS (Geographical
>Information System) for further analysis.

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