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.
data(nztrees)"ppp"
representing the point pattern of tree locations.
The Cartesian coordinates are in feet. See ppp.object for details of the format of a
point pattern object.
nzsub <- nztrees[ , owin(c(0,148),c(0,95)) ]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.