# Computes kriging weights Computes the weights assign for each data point in simple and ordinary krigring ```r krweights(coords, locations, krige) ``` ## Arguments - `coords`: matrix with data coordinates - `locations`: matrix with coordinates of the prediciton points - `krige`: kriging parameters. See krige.control in krige.conv ## Returns A matrix of weights ## Examples ```r ## Figure 8.4 in Webster and Oliver (2001), see help(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)) ## ## SK vs OK ## plot(c(-10,130), c(-10,130), ty="n", asp=1) points(rbind(coords, x1)) KC5 <- krige.control(cov.pars=c(0.382,50)) w5 <- krweights(wo$coords, loc=x1, krige=KC5) KC6 <- krige.control(type="sk", beta=2, cov.pars=c(0.382,50)) w6 <- krweights(wo$coords, loc=x1, krige=KC6) text(coords[,1], 5+coords[,2], round(w5, dig=3)) text(coords[,1], -5+coords[,2], round(w6, dig=3)) ## plot(c(-10,130), c(-10,130), ty="n", asp=1) points(rbind(coords, x1)) KC7 <- krige.control(cov.pars=c(0.382,0)) w7 <- krweights(wo$coords, loc=x1, krige=KC7) KC8 <- krige.control(type="sk", beta=2, cov.pars=c(0.382,0)) w8 <- krweights(wo$coords, loc=x1, krige=KC8) text(coords[,1], 5+coords[,2], round(w7, dig=3)) text(coords[,1], -5+coords[,2], round(w8, dig=3)) ```

krweights function