Sliding window for matrix data

This program applies a function defined by the user, using a moving window (circle area or square) and assigning the value to the focal pixel.

eco.slide.matrix(mat, r, slide, fun, window = c("square", "circle"),
  within = TRUE)

Arguments

mat	Input raster matrix.
r	Half a side for square, radius for circle, diagonal length for rhombus.
slide	Number of elements between two focal pixels, for column and row dimension
fun	Function to apply in each focal pixel.
window	Window type. Default "square".
within	Should the function be computed in focal pixels of the borders, only if the area is within the matrix? Default TRUE.

Examples

# NOT RUN {
data(eco.test)
ras <- matrix(eco[["P"]][, 1], 15, 15)
image(ras)
ras.square <- eco.slide.matrix(ras, 1, 1, mean, "square")
image(ras.square)

# or allowing more control over the function:
ras.square <- eco.slide.matrix(ras, r = 3, slide = 1, function(x) mean(x, na.rm = TRUE), "square")
image(ras.square)

# sliding a circle:
ras.circle <- eco.slide.matrix(ras, r = 3, slide = 1, mean, "circle", within = FALSE)
image(ras.circle)

# }