[R-sig-Geo] R: gstat cross validation for accuracy ordinary kriging vs IDW

2014-05-22 Thread Michele Fiori
Hi Moshood, I think you can do this way Ordinary kriging to create kriging prediction orkrig - krige(yield ~ 1, canmod.sp, newdata = grid, model=exp.mod,nmax=20) OrdKrigecv - Krige.cv(yield ~ 1, canmod.sp, model=exp.mod,nmax=20) RMSE.ok -

Re: [R-sig-Geo] Create a simple spatial grid

2014-05-22 Thread Barry Rowlingson
On Wed, May 21, 2014 at 5:14 PM, Remi Genevest rgenev...@free.fr wrote: Thanks a lot Barry. Your post perfectly matches what I was looking for. Well now if I want to do a coarser grid covering Europe, what I should do is doing more or less the same thing, just to change the resolution, right?

Re: [R-sig-Geo] gstat cross validation for accuracy ordinary kriging vs IDW

2014-05-22 Thread Moshood Agba Bakare
Hi Michele, I tried the script as advised but get the error message ordkrigcv- krige.cv(yield ~ 1, canmod.sp, newdata = grid, model=exp.mod,nmax=20)Error in gstat(g = NULL, id = var1, formula = formula, data = locations, : unused argument(s) (newdata = S4 object of class SpatialPixels)

Re: [R-sig-Geo] gstat cross validation for accuracy ordinary kriging vs IDW

2014-05-22 Thread Alaba Boluwade
Hi Moshood, You did not follow what Michele sent to you: ordkrigcv- krige.cv(yield ~ 1, canmod.sp, model=exp.mod, nmax=20) try: ?krige.cv from the gstat library to see what you need to supply for the function. I would also advise you try reading Bivand et al (2008). Some of these

Re: [R-sig-Geo] Create a simple spatial grid

2014-05-22 Thread Remi Genevest
Alright ! You pointed out my goal indeed... but 100meters by 100meters is still a bit too high for a map over Europe. So, this is what I have done : ### create a grid raster ll = CRS(+init=epsg:4326) origin = SpatialPoints(cbind(7,40),ll) grid = raster() ## make resolution ie 0.008 min par

Re: [R-sig-Geo] Create a simple spatial grid

2014-05-22 Thread Barry Rowlingson
On Thu, May 22, 2014 at 7:44 PM, Remi Genevest rgenev...@free.fr wrote: Alright ! You pointed out my goal indeed... but 100meters by 100meters is still a bit too high for a map over Europe. So, this is what I have done : ### create a grid raster ll = CRS(+init=epsg:4326) origin =