SpaDES.tools (version 0.2.0)

randomPolygons: randomPolygons

Description

Produces a raster of random polygons. These are built with the spread function internally.

Produces a SpatialPolygons object with 1 feature that will have approximately an area equal to hectares, and a centre at approximately x

Usage

randomPolygons(ras = raster(extent(0, 15, 0, 15), res = 1, vals = 0),
  numTypes = 2, ...)
randomPolygon(x, hectares)

Arguments

ras

A raster that whose extent will be used for the randomPolygons.

numTypes

Numeric value. The number of unique polygon types to use.

...

Other arguments passed to spread. No known uses currently.

x

Either a SpatialPoints or matrix with 2 dimensions, 1 row, with with the approximate centre of the new random polygon to create. If matrix, then longitude and latitude are assumed (epsg:4326)

hectares

A numeric, the approximate area in hectares of the random polygon.

Value

A map of extent ext with random polygons.

A SpatialPolygons object, with approximately the area request, centred approximately at the coordinates requested.

See Also

spread, raster, randomPolygons

gaussMap and randomPolygons

Examples

# NOT RUN {
library(quickPlot)

set.seed(1234)
Ras <- randomPolygons(numTypes = 5)
if (interactive()) {
  clearPlot()
  Plot(Ras, cols = c("yellow", "dark green", "blue", "dark red"))
}

library(raster)
# more complex patterning, with a range of patch sizes
a <- randomPolygons(numTypes = 400, raster(extent(0, 50, 0, 50), res = 1, vals = 0))
a[a<320] <- 0
a[a>=320] <- 1
suppressWarnings(clumped <- clump(a)) # warning sometimes occurs, but not important
aHist <- hist(table(getValues(clumped)), plot = FALSE)
if (interactive()) {
  clearPlot()
  Plot(a)
  Plot(aHist)
}

library(sp)
b <- SpatialPoints(cbind(-110, 59))
a <- randomPolygon(b, 1e4)
plot(a)
points(b, pch = 19)

# }