Diggle's Heather Data
The spatial mosaic of vegetation of the heather plant (Calluna vulgaris) recorded in a 10 by 20 metre sampling plot in Sweden.
A list with three entries, representing the same data at
different spatial resolutions:
coarse original heather data, 100 by 200 pixels
medium current heather data, 256 by 512 pixels
fine finest resolution data, 778 by 1570 pixels
Each of these entries is an object of class
containing a binary pixel mask.
History of analysis of data
The data were recorded, presented and analysed by Diggle (1983). He proposed a Boolean model consisting of discs of random size with centres generated by of a Poisson point process. Renshaw and Ford (1983) reported that spectral analysis of the data suggested the presence of strong row and column effects. However, this may have been attributable to errors in the run-length encoding of the original data.
Hall (1985) and Hall (1988, pp 301-318) took a bootstrap approach.
Ripley (1988, pp. 121-122, 131-135] used opening and closing functions to argue that a Boolean model of discs is inappropriate.
Cressie (1991, pp. 763-770) tried a more general Boolean model.
Cressie, N.A.C. (1991) Statistics for Spatial Data. John Wiley and Sons, New York.
Diggle, P.J. (1981) Binary mosaics and the spatial pattern of heather. Biometrics 37, 531-539.
Hall, P. (1985) Resampling a coverage pattern. Stochastic Processes and their Applications 20 231-246.
Hall, P. (1988) An introduction to the theory of coverage processes. John Wiley and Sons, New York.
Renshaw, E. and Ford, E.D. (1983) The interpretation of process from pattern using two-dimensional spectral analysis: Methods and problems of interpretation. Applied Statistics 32 51-63. Ripley, B.D. (1988) Statistical Inference for Spatial Processes. Cambridge University Press.