Produces a raster of with random polygons of varying parameters, using the
Modified Random Cluster algorithm of Saura and Martinez-Millan (2000).
Usage
randomPolygons(ras = raster(extent(0, 15, 0, 15), res = 1), p = 0.1,
A = 0.3, speedup = 1, numTypes = 1, minpatch = 2, ...)
Arguments
ras
A raster that whose extent will be used for the randomPolygons
p
Numeric vector. Parameter to control fragmentation.
If this is a vector, then there will be a polygon map produced
with length(p) unique levels.
A
Numeric vector. Parameter for expected proportion of habitat.
If this is a vector, then there will be a polygon map produced
with length(A) unique levels.
speedup
An index of how much faster than normal to generate maps.
This is achieved by aggregating then disagregating, so
that the resulting raster is the same extent as ras.
numTypes
Numeric value. The number of unique polygon types to use.
This will be overridden by p, A or
minpatch, if any of these are vectors.
minpatch
Numeric vector. Integer minimum size of patch.
If this is a vector, there will be a polygon map produced
with length(A) unique levels.
This is a wrapper for the randomHabitat function in the
secr package.
The two main additions are the speedup argument which allows for
faster map generation for large rasters and addition of multiple unique
polygon values, using code drawn from
http://www.guru-gis.net/generate-a-random-landscape/.
References
Saura, S. and Martinez-Millan, J. (2000) Landscape patterns simulation with a modified random clusters method. Landscape Ecology, 15, 661--678.