set_points_from_raster: Simulate points using input raster as weights

In NINAnor/oneimpact: Tools for the assessment of the cumulative impacts of anthropogenic features in ecological studies

Simulate points using input raster as weights

Description

This function simulates point patterns in space using the values of an input raster as weights or probabilities for selecting a point in a given location. It was designed to simulate points based on neutral landscape models but it works with other input rasters as well.

Usage

set_points_from_raster(base_raster, n_features = 1000)

Arguments

base_raster	⁠[RasterLayer]⁠ Input raster used for defining the weights.
n_features	⁠[integer(1)=1000]⁠ Total number of features to spread in space.

Details

The function works by first selecting random pixels in the landscape and finding their centers, then adding random variation within each pixel to define the final point locations. It was based on this StackExchange very useful answer from "Spacedman": https://gis.stackexchange.com/questions/224321/randomly-generate-points-using-weights-from-raster

TO IMPROVE: implement with terra package

Value

A data.frame with the (x,y) coordinates of the simulated points.

Examples

#-----
# minimal example

# example based on
# https://gis.stackexchange.com/questions/224321/randomly-generate-points-using-weights-from-raster
library(raster)

# raster
set.seed(12)
r <- raster::raster(matrix(runif(12),3,4))

# points
pts <- set_points_from_raster(r, n_features = 300)

# plot
raster::plot(r)
points(pts)

# with terra
r <- terra::rast(r)
# points
pts <- set_points_from_raster(r, n_features = 300)

NINAnor/oneimpact documentation built on June 14, 2025, 12:27 a.m.