GSTAT: Optimize power value for IDW
Zev Ross wrote:
Hi All, ArcGIS has a nice little button that calculates the optimal power value to use for inverse distance weighting based on cross-validation and RMSPE. Just wondering if anyone had written something similar in R -- I'm using GSTAT and I'd like to avoid back and forth with ArcGIS (and obviously I'd like to avoid writing it myself as well!). Zev
Hi Zev, It seems to me that you want to perform some kind of optimal automatic interpolation. As an alternative to the methods presented by Alessandro, Edzer and myself you could try the automap package I wrote for my PhD. It provides a means of automatically performing kriging (in my view superior to IDW, for example it takes clustering of observations into account; it provides an estimate of prediction uncertainty). The package is not yet available from CRAN, but the latest version can be downloaded from my website: http://intamap.geo.uu.nl/~paul/Downloads.html There is a .zip binary file for Windows and a .tar.gz file for Linux. After loading the package, the command demo(automap) will give you a good impression of the package. Any feedback on the documentation and structure of the package is most welcome. cheers, Paul
Drs. Paul Hiemstra Department of Physical Geography Faculty of Geosciences University of Utrecht Heidelberglaan 2 P.O. Box 80.115 3508 TC Utrecht Phone: +31302535773 Fax: +31302531145 http://intamap.geo.uu.nl/~paul