krweights {geoR} | R Documentation |
Computes the weights assign for each data point in simple and ordinary krigring
krweights(coords, locations, krige)
coords |
matrix with data coordinates |
locations |
matrix with coordinates of the prediciton points |
krige |
kriging parameters. See krige.control in krige.conv |
A matrix of weights
## Figure 8.4 in Webster and Oliver (2001), see help(wo) data(wo) attach(wo) par(mfrow=c(2,2)) plot(c(-10,130), c(-10,130), ty="n", asp=1) points(rbind(coords, x1)) KC1 <- krige.control(cov.pars=c(0.382,90.53)) w1 <- krweights(wo$coords, loc=x1, krige=KC1) text(coords[,1], 5+coords[,2], round(w1, dig=3)) ## plot(c(-10,130), c(-10,130), ty="n", asp=1) points(rbind(coords, x1)) KC2 <- krige.control(cov.pars=c(0.282,90.53), nug=0.1) w2 <- krweights(wo$coords, loc=x1, krige=KC2) text(coords[,1], 5+coords[,2], round(w2, dig=3)) ## plot(c(-10,130), c(-10,130), ty="n", asp=1) points(rbind(coords, x1)) KC3 <- krige.control(cov.pars=c(0.082,90.53), nug=0.3) w3 <- krweights(wo$coords, loc=x1, krige=KC3) text(coords[,1], 5+coords[,2], round(w3, dig=3)) ## plot(c(-10,130), c(-10,130), ty="n", asp=1) points(rbind(coords, x1)) KC4 <- krige.control(cov.pars=c(0,90.53), nug=0.382, micro=0.382) w4 <- krweights(wo$coords, loc=x1, krige=KC4) text(coords[,1], 5+coords[,2], round(w4, dig=3))