[R-sig-Geo] Spatial interpolation possibilities
p.hiemstra at geo.uu.nl
Tue Dec 14 10:29:36 CET 2010
On 12/03/2010 03:38 PM, Arnaud Mosnier wrote:
> Dear GeoUseRs,
> > From the large number of methods that can be used to spatially interpolate
> data, we tried several of them (Inverse Distance Weighted, Natural
> Neighbour, Spline, Kriging, Co-Kriging) on our dataset. We used ArcGIS to
> apply the first three and R for kriging and test possibilities of
> We do not have external independent data to test results of interpolations.
> The solution is probably to do a kind of cross-validation but doing it into
> ArcGIS seems difficult to implement.
> I know that I can do Inverse distance weighted interpolation in R but ...
> - Is it possible to do Natural Neighbour and Spline interpolation in R ? And
> if yes how ?
Spline is possible, look at the Tps function from the fields package.
I'm not sure on Natural Neighbor, but voronoi tessalations are available
> ArcGIS tools propose to consider "barriers" when using Inverse Distance
> Weighted and Spline tools. Thus, for example, interpolation occurring North
> from an island do not consider information located South of this island ...
> a quite important thing in our case.
> - I wondering if it is possible to do the same with gstat or another package
You could split up the dataset in two regions and interpolate them
Finally, if you want to cross-validate, look at the compare.cv function
from the automap package. It provides statistics and some spatial plots
of the cross-validation residuals which I found very useful (I wrote
them myself ;)). When cross-validating non-gstat interpolations you need
to make sure that the output of the cross-validation is compatible (i.e.
a SpatialPointsDataFrame with a few specific attributes). I have an
example of how to do this with Tps, which can serve as inspiration. If
you are interested I can send the code off list.
> Thanks for your help !
> [[alternative HTML version deleted]]
> R-sig-Geo mailing list
> R-sig-Geo at r-project.org
Paul Hiemstra, MSc
Department of Physical Geography
Faculty of Geosciences
University of Utrecht
P.O. Box 80.115
3508 TC Utrecht
Phone: +3130 253 5773
currently @ KNMI
More information about the R-sig-Geo