raster (version 3.1-5)

focalWeight: Focal weights matrix

Description

Calculate focal ("moving window") weight matrix for use in the focal function. The sum of the values adds up to one.

Usage

focalWeight(x, d, type=c('circle', 'Gauss', 'rectangle'))

Arguments

x

Raster* object

d

numeric. If type=circle, the radius of the circle (in units of the CRS). If type=rectangle the dimension of the rectangle (one or two numbers). If type=Gauss the size of sigma, and optionally another number to determine the size of the matrix returned (default is 3 times sigma)

type

character indicating the type of filter to be returned

Value

matrix that can be used in focal

Examples

# NOT RUN {
r <- raster(ncols=36, nrows=18, xmn=0)
# Gaussian filter for square cells
gf <- focalWeight(r, 2, "Gauss")
# }