focalMat: Focal weights matrix
In terra: Spatial Data Analysis

focalMat

R Documentation

Focal weights matrix

Description

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

Usage

focalMat(x, d, type=c('circle', 'Gauss', 'rectangle'), fillNA=FALSE)

Arguments

`x`	SpatRaster
`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*sigma)
`type`	character indicating the type of filter to be returned
`fillNA`	logical. If `TRUE`, zeros are set to `NA` such that they are ignored in the computations. Only applies to `type="circle"`

Value

matrix that can be used with focal

Examples

r <- rast(ncols=180, nrows=180, xmin=0)
focalMat(r, 2, "circle")

focalMat(r, c(2,3), "rect")

# Gaussian filter for square cells
gf <- focalMat(r, 1, "Gauss")

terra documentation built on Oct. 14, 2024, 5:07 p.m.