Thanks for the clear report Mauricio - very helpful. Package gstat version 0.9-80, now submitted to CRAN, should resolve this.
With best regards, On 04/01/2011 09:59 AM, Mauricio Zambrano wrote: > Dear list, > > While using the 'krige' function of gstat, I realised that -in some > cases- the spatial extent of the object obtained with the 'krige' > function is different from the spatial extent of the object provided > as 'newdata' argument to the function. > > In particular this occurred when the map passed as 'new data' argument > ('SpatialGridDataFrame' object, read with readGDAL) had some empty > rows in the upper part of the map. > > Below there is a reproducible example (R version 2.12.2 and gstat_0.9-79 ): > > > ----------------- START -------------------- > library(gstat) > > data(meuse) > coordinates(meuse) = ~x+y > > data(meuse.grid) > > # Removing unnecessary bands > meuse.grid$part.a <- NULL > meuse.grid$part.b <- NULL > meuse.grid$dist <- NULL > meuse.grid$ffreq <- NULL > gridded(meuse.grid) = ~x+y > > # Getting the class of 'meuse.grid' (SpatialPixelsDataFrame) > class(meuse.grid) > #"SpatialPixelsDataFrame" > > summary(meuse.grid) > #nrows=104 > #ncols=78 > > # B) Transforming 'meuse.grid' from 'SpatialPixelsDataFrame' to > 'SpatialGridDataFrame' > meuse.grid <- as(meuse.grid,'SpatialGridDataFrame') > > # Variogram > m <- vgm(.59, "Sph", 874, .04) > > x1 <- krige(log(zinc)~1, locations=meuse, newdata=meuse.grid, model = m) > summary(x1) > #nrows=104 > #ncols=78 > > # In this example, the resulting object 'x1' has the same amount of > rows and column of 'meuse.grid' > > ################################### > # Putting some NA's in 'meuse.grid' > meuse.grid@data[1:156,] <- NA > summary(meuse.grid) > #nrows=104 > #ncols=78 > > x2 <- krige(log(zinc)~1, locations=meuse, newdata=meuse.grid, model = m) > summary(x2) > #nrows=102 > #ncols=78 > > ----------------- END -------------------- > > In the latest example, why 'x2' has 102 rows if 'meuse.grid' has 104 ? > > > Thanks in advance for any help, > > Mauricio Zambrano B. > -- 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