Hi Greg, Just a small remark: it would not be a special treatment because I am anyway 80% of my time located in Amsterdam ;)
Edzer, thanx for fixing this problem. I did run kriging on LatLon projected data a lot actually. LatLon coordinates are especially attractive because you can then directly export the resulting maps to Google Earth. cheers, Tom Hengl http://spatial-analyst.net -----Original Message----- From: [EMAIL PROTECTED] on behalf of Greg Lee Sent: Fri 31/10/2008 9:45 AM To: Edzer Pebesma Cc: r-sig-geo@stat.math.ethz.ch Subject: Re: [R-sig-Geo] gstat::variogram - distance calculation isincorrect; kriging on sphere No sign of sp 0.9-27 at this end (Melbourne, Australia) yet. Interesting that it should take so long. I temporarily reset my repository to access the updates. Croatia already has sp 0.9-28, along with gstat 0.9-53. (Does Tomislav receive special treatment?) Your example now works perfectly. Thank you. Greg. 2008/10/31 Edzer Pebesma <[EMAIL PROTECTED]> > That's right; my fault that I sent the email and updated the sp package on > CRAN almost at the same time. The new sp (0.9-27 would suffice) should now > have propagated to your mirror, simply update your sp package again and it > should work. Let me know if it doesn't. > -- > Edzer > > Greg Lee wrote: > >> Hello Edzer, >> >> I was curious to run the example you provided (using the latest CRAN >> versions of all packages), but as written the line >> >> >> >>> idw.spdf = as(idw.out, "SpatialPolygonsDataFrame") >>> >>> >> >> produces >> >> Error in as(idw.out, "SpatialPolygonsDataFrame") : no method or default >> for >> coercing "SpatialPixelsDataFrame" to "SpatialPolygonsDataFrame" >> Regards, >> Greg. >> >> >> 2008/10/30 Edzer Pebesma <[EMAIL PROTECTED]> >> >> >> >>> Dear all, >>> >>> In continuation of this thread, I've spent some time looking at kriging >>> on >>> the sphere, corrected some bugs, and need further help. >>> >>> First of all, distances for covariances on the sphere were computed >>> incorrectly as well in gstat, so I hope not too many people have been >>> relying on this--kriging seemed to happen still in some Euclidian mode. >>> The >>> good news is that it seems to work now (gstat 0.9-53, accepted on CRAN). >>> Inverse distance interpolation for spherical data seemed to work already. >>> >>> Covariances on the sphere now work, but the models present do not include >>> those specially deviced for spherical data. Can anyone provide me with or >>> point me to useful, preferably simple covariance functions that are >>> positive >>> definite on the sphere? The example below seems to work but in certain >>> cases >>> without nugget the interpolation may go crazy. You'll need to update your >>> sp >>> to 0.9-27 to run it (also accepted on CRAN). >>> >>> Below is an example script. It also needs the new sp and gstat versions. >>> >>> library(gstat) >>> library(rgdal) >>> world = expand.grid(long=seq(-177.5,177.5,5),lat=seq(-87.5,87.5,5)) >>> world.sp = SpatialPixels(SpatialPoints(world,CRS("+proj=longlat"))) >>> plot(world.sp,axes=T) >>> >>> >>> pts=data.frame(long=runif(100,-180,180),lat=runif(100,-90,90),val=rnorm(100)) >>> coordinates(pts)=~long+lat >>> proj4string(pts)=CRS("+proj=longlat") >>> points(pts,col='red') >>> >>> # inverse distance interpolation on the sphere: >>> idw.out = idw(val~1,pts,world.sp) >>> image(idw.out, axes = TRUE, ylim = c(-90,90)) >>> points(pts, pch=3) >>> idw.spdf = as(idw.out, "SpatialPolygonsDataFrame") >>> newproj = CRS("+proj=moll") >>> idw.spdf.moll = spTransform(idw.spdf, newproj) >>> spplot(idw.spdf.moll, "var1.pred",col.regions=bpy.colors(),col=0, >>> sp.layout = list(sp.points, spTransform(pts, newproj), col = 'black')) >>> >>> # kriging on the sphere >>> kr.out = krige(val~1,pts,world.sp,vgm(1, "Exp", 3000)) >>> idw.spdf.moll$kr = kr.out[[1]] >>> spplot(idw.spdf.moll, "kr", col.regions=bpy.colors(), col=0, >>> sp.layout = list(sp.points, spTransform(pts, newproj), col = 'black')) >>> >>> -- >>> 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.springer.com/978-0-387-78170-9 [EMAIL PROTECTED] >>> >>> >>> _______________________________________________ >>> R-sig-Geo mailing list >>> R-sig-Geo@stat.math.ethz.ch >>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo >>> >>> >>> >>> >> >> [[alternative HTML version deleted]] >> >> ------------------------------------------------------------------------ >> >> _______________________________________________ >> R-sig-Geo mailing list >> R-sig-Geo@stat.math.ethz.ch >> 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.springer.com/978-0-387-78170-9 [EMAIL PROTECTED] > > -- -------------- Greg Lee Biometrician Tasmanian Institute of Agricultural Research New Town Research Laboratories University of Tasmania 13 St Johns Avenue, New Town, 7008 Australia Ph: +613 6233 6858 Fax: +613 6233 6145 [[alternative HTML version deleted]] [[alternative HTML version deleted]]
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