On 03/20/2011 03:30 AM, JIN HUR wrote: > Hi All, > > I'm working on prediction analysis using Universal Kriging (UK). > I have two questions. > > 1) Formula in UK > My input data are latitude and longitude and wind speed to predict wind > speed at unmeasured points. > In this case, how do I make the formula in krige function of UK? For > example, in meuse case, usually, formula is "log(zinc)~sqrt(dist)".
Wind.speed ~ Longitude+Latitude > > 2) Distance in km > In semivariance, how do I calculate the distance (h) in km in > semivariogram using longitude (degree) and latitude (degree)? If you set the CRS such that is.projected reports FALSE, great distances will be computed assuming long/lat values. For instance: > library(rgdal) > proj4string(meuse) <- CRS("+init=epsg:28992") > meuse.ll = spTransform(meuse, CRS("+init=epsg:4326")) > is.projected(meuse.ll) [1] FALSE > variogram(log(zinc)~dist+x+y,meuse)[1:3,] np dist gamma dir.hor dir.ver id 1 57 79.29244 0.0945474 0 0 var1 2 299 163.97367 0.1576838 0 0 var1 3 419 267.36483 0.1837920 0 0 var1 Distances reported are in m. > > My data are as follows: > > Longitude Latitude Wind.Speed > 1 -87.545 41.757 2.387500 > 2 -87.669 41.979 2.925000 > 3 -87.568 41.708 2.137500 > 4 -87.726 41.739 2.87500 > 5 -87.558 41.616 3.025000 > 6 -87.792 41.984 3.242857 > 7 -87.990 41.668 3.950000 > 8 -87.753 41.855 1.687500 > 9 -87.898 42.039 3.687500 > 10 -87.676 42.062 3.700000 > > > Thanks, > > Best Regards, > Jin > > [[alternative HTML version deleted]] > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo -- Edzer Pebesma Institute for Geoinformatics (ifgi), University of Münster Weseler Straße 253, 48151 Münster, Germany. Phone: +49 251 8333081, Fax: +49 251 8339763 http://ifgi.uni-muenster.de http://www.52north.org/geostatistics e.pebe...@wwu.de _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo