Description Usage Arguments Value References See Also Examples

This function provides the basic quantities which are used in
forming a variety of diagnostics for checking the quality of
regression fits for trend surfaces calculated by `surf.ls`

.

1 2 3 4 |

`object, x` |
Fitted trend surface model from |

`div` |
scaling factor for influence circle radii in |

`add` |
add influence plot to existing graphics if |

`border, col, pch, cex, ...` |
additional graphical parameters |

`trls.influence`

returns a list with components:

`r` |
raw residuals as given by |

`hii` |
diagonal elements of the Hat matrix |

`stresid` |
standardised residuals |

`Di` |
Cook's statistic |

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.

Venables, W. N. and Ripley, B. D. (2002)
*Modern Applied Statistics with S.* Fourth edition. Springer.

`surf.ls`

, `influence.measures`

, `plot.lm`

1 2 3 4 5 6 7 8 9 10 11 12 | ```
library(MASS) # for eqscplot
data(topo, package = "MASS")
topo2 <- surf.ls(2, topo)
infl.topo2 <- trls.influence(topo2)
(cand <- as.data.frame(infl.topo2)[abs(infl.topo2$stresid) > 1.5, ])
cand.xy <- topo[as.integer(rownames(cand)), c("x", "y")]
trsurf <- trmat(topo2, 0, 6.5, 0, 6.5, 50)
eqscplot(trsurf, type = "n")
contour(trsurf, add = TRUE, col = "grey")
plot(topo2, add = TRUE, div = 3)
points(cand.xy, pch = 16, col = "orange")
text(cand.xy, labels = rownames(cand.xy), pos = 4, offset = 0.5)
``` |

spatial documentation built on May 29, 2017, 8 p.m.

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