Re: [R-sig-Geo] overlay fx, consistent topology, sample a point on a 'patch edge'

2008-02-07 Thread Roger Bivand
On Thu, 7 Feb 2008, Edzer Pebesma wrote: > Ilona Naujokaitis-Lewis wrote: >> NO >> >> Dear list-serve, >> Thanks in advance to all those who help out with the inquiries, it is has >> helped me numerous times. Here go my questions... >> >> I am trying to vary existing landscapes which are composed

Re: [R-sig-Geo] cross-validation

2008-02-07 Thread Edzer Pebesma
Marta Rufino wrote: > Great! Hi Marta, I now have in the example section of gstat.cv help: # multivariable; thanks to M. Rufino: meuse.g <- gstat(id = "zn", formula = log(zinc) ~ 1, data = meuse) meuse.g <- gstat(meuse.g, "cu", log(copper) ~ 1, meuse) meuse.g <- gstat(meuse.g, model = vgm(1, "Sph

Re: [R-sig-Geo] overlay fx, consistent topology, sample a point on a 'patch edge'

2008-02-07 Thread Edzer Pebesma
Ilona Naujokaitis-Lewis wrote: > NO > > Dear list-serve, > Thanks in advance to all those who help out with the inquiries, it is has > helped me numerous times. Here go my questions... > > I am trying to vary existing landscapes which are composed of habitat > (patches) and non-habitat. My goals ar

Re: [R-sig-Geo] cross-validation

2008-02-07 Thread Marta Rufino
Great! This works wonderfully...maybe would be nice if you add it to the example in the help page :-) Further comments in /CV/... from the gstat.cv output, which cross-validation measures should be considered when establishing the performance of kriging, in relation to other methods, for examp

Re: [R-sig-Geo] cross-validation

2008-02-07 Thread Edzer Pebesma
That was not the problem, the problem was that you used meuse.g instead of meuse.fit to pass on to gstat.cv. For meuse.g, you have perfect correlation between Cu and Zn, so that collocated observations (meaning a Zn and a Cu observation at each obs location) act as a duplicate in univarite krig