PercolationMap: Generate Random Category Landscape
In ecomodtools: Ecological Modelling Toolbox

Description Usage Arguments Value Author(s) References See Also Examples

A function to generate a multidimensional landscape with each cell randomly assigned a category number such that the total ratio of category types accross the landscape corresponds to a proportion vector input.

1	PercolationMap(DimExtents, Props, Cat.Labels = 1:length(Props))

`DimExtents`	An integer vector with the length of the desired output in each dimension. `length(DimExtents)` gives the number of dimensions in the output.
`Props`	An integer vector with a each element containing the number of cells to assign to each category type. `length(Props)` gives the number of categories to assign. Note that `prod(DimExtents)` must equal to or less than `sum(Props)` otherwise an error is displayed. If `prod(DimExtents)` is less than `sum(Props)` then all remaining cells are assigned to an `NA` category.
`Cat.Labels`	A vector of category labels to attach to each of the assigned category types. If `length(Cat.Labels)` is less than `length(Props)` then `Cat.Labels` is recycled.

A vector of length prod(DimExtents) and with a dimensional extent attribute set to DimExtents. Each element contains the corresponding category label given in Cat.Labels to the assigned category type.

Joseph Chipperfield <joechip90@googlemail.com>

Gardner, R. H., Milne, B. T., Turner, M. G. and O'Neill, R. V. (1987) Neutral models for the analysis of broad-scale landscape pattern. Landscape Ecology, 1, 19-28.

With, K. A. (1997) The application of neutral landscape models in conservation biology. Conservation Biology, 11, 1069-1080.

With, K. A. and King A. W. (1997) The use and misuse of neutral landscapes models in ecology. Oikos, 79, 219-229.

HierarchicalCurdling SpectralSynthesis

# Create a 100 x 100 landscape with 3000 "grass" cells, 2000 "sand" cells, and
# 5000 "bog" cells
dims.in <- rep(100,2)				# Dimension extent
props <- c(3000, 2000, 5000)			# Proportions of each habitat type
cat.labels <- c("grass", "sand", "bog")		# Category labels
output.map <- PercolationMap(dims.in, props, cat.labels)
# Code the outputs into values for display
coded.map <- ifelse(output.map == "grass", 1, ifelse(output.map == "sand", 2, 3))
image(coded.map, col = c("green", "yellow", "brown"))