ineigh: Get neighbor indices

In ptarroso/gameR: A small useless package to play games in R with your data

Description

A fast function to get neighbor indices.

Usage

ineigh(i, n, nrow, ncol)

Arguments

i	Source pixel ID number.
n	Number of neighbors to get. For a 3x3 neighborhood, this value is set to 1 (a single neighbor to each of the eight sides of the pixel).
nrow	The number of rows in the raster.
ncol	The number of columns in the raster.

Details

This is a fast function to get the indices of the neighbors to a pixel. It does not require the matrix/raster object, only the number of rows and columns, to find the neighbors. It returns the sorted indices for the pixel, including the focal pixel. If at the edge, it returns NAs so the length is always the number of neighbors asked.

Value

A vector with integer indices.

Author(s)

Pedro Tarroso

Examples

	# the 3x3 neighbors of pixel 34, on a matrix with 200 rows and columns
	ineigh(34, 1, 200, 200)

ptarroso/gameR documentation built on Nov. 17, 2021, 12:33 a.m.