get_resdist {wingen}

Get a matrix of resistance distances for resist_gd

Description

Create a distance matrix based on coordinates and a connectivity layer. The output is a distance matrix where rows represent cells on the landscape and columns represent individual locations on the landscape. Each value is the resistance distance between each sample and each cell calculated using the gdistance package. This matrix is used by resist_gd. If coords_only = TRUE, the result is a distance matrix for the sample coordinates only.

Usage

get_resdist(
  coords,
  lyr,
  fact = 0,
  transitionFunction = mean,
  directions = 8,
  geoCorrection = TRUE,
  coords_only = FALSE
)

Arguments

coords

coordinates of samples as sf points, a two-column matrix, or a data.frame representing x and y coordinates (see Details for important information about projections)

lyr

conductivity layer (higher values should mean greater conductivity) for generating distances. Can be either a SpatRaster or RasterLayer.

fact

aggregation factor to apply to lyr (defaults to 0; note: increasing this value reduces computational time)

transitionFunction

function to calculate transition values from grid values (defaults to mean)

directions

directions in which cells are connected (4, 8, 16, or other), see adjacent (defaults to 8)

geoCorrection

whether to apply correction to account for local distances (defaults to TRUE). Geographic correction is necessary for all objects of the class Transition that are either: (1) based on a grid in a geographic (lonlat) projection and covering a large area; (2) made with directions > 4 (see geoCorrection for more details).

coords_only

whether to return distances only for sample coordinates

Value

a distance matrix used by resist_gd

Examples

load_mini_ex()
distmat <- get_resdist(mini_coords, mini_lyr)