New Zealand Trees Point Pattern
The data give the locations of trees in a forest plot.
They were collected by Mark and Esler (1970) and were extracted and analysed by Ripley (1981, pp. 169-175). They represent the positions of 86 trees in a forest plot approximately 140 by 85 feet. Ripley discarded from his analysis the eight trees at the right-hand edge of the plot (which appear to be part of a planted border) and trimmed the window by a 5-foot margin accordingly.
An object of class
representing the point pattern of tree locations.
The Cartesian coordinates are in feet.
ppp.object for details of the format of a
point pattern object.
Mark and Esler (1970), Ripley (1981).
To trim a 5-foot margin off the window, type
nzsub <- nztrees[ , owin(c(0,148),c(0,95)) ]
Ripley, B.D. (1981) Spatial statistics. John Wiley and Sons.
Mark, A.F. and Esler, A.E. (1970) An assessment of the point-centred quarter method of plotless sampling in some New Zealand forests. Proceedings of the New Zealand Ecological Society 17, 106--110.