surf.ls.
trls.influence(object)
plot.trls(x, border = 1, col = NA, pch = 4, cex = 0.6,
add = F, div = 8, ...)
surf.ls
plot.trls
TRUE
trls.influence returns a list with:
residuals.trls
Unwin, D. J., Wrigley, N. (1987) Towards a general-theory of control point distribution effects in trend surface models. Computers and Geosciences, 13, 351-355.
library(MASS)
topo2 <- surf.ls(2, topo)
infl.topo2 <- trls.influence(topo2)
cand <- as.data.frame(infl.topo2)[abs(infl.topo2$stresid) > 1.5,]
cand
cand.xy <- topo[as.integer(dimnames(cand)[[1]]), c("x", "y")]
trsurf <- trmat(topo2, 0, 6.5, 0, 6.5, 50)
eqscplot(trsurf, type="n")
#under S need to choose appropriate colour numbers
contour(trsurf, add=T, col="grey")
plot(topo2, add=T, div=3)
points(cand.xy, pch=16, col="orange")