Re: [R-sig-Geo] FW: Interpolation option: IDW or OK?

2009-02-11 Thread Edzer Pebesma
I can think of two reasons, without having looked at anything else than your message: 1. Range=162 may mean a different thing for the exponential model; for gstat it means the range parameter as in c1(1-exp(h/a)). This is all documented. In ArcGIS it might mean something like c1(1-exp(h/(3a)); f

[R-sig-Geo] FW: Interpolation option: IDW or OK?

2009-02-11 Thread Yong Li
Hi Edzer, I found a problem with gstat "krige" prediction if I am correct this time. For example, with OLSENP variable in my dataset, I developed a theoretical model for log(OLSENP) variogram: model=exp, c0=0.2019, c1=0.2218 and Range=162 meters. By using this model, I predicted the OLSENP surface