adj_mat: Adjacency matrix.

Description

adj_mat builds an upper-triangular adjacency matrix for the set of points/areas in a chosen distance range.

Usage

adj_mat(dist.mat, dd0 = 0, dd1)

Arguments

dist.mat

An upper-triangular matrix of Euclidean distances, as returned by euclid_dist().

dd0

Numeric, minimum distance for the neighbourhood/couples/pairs, 0 by default.

dd1

Numeric, maximum distance for the neighbourhood/couples/pairs.

Value

An \(n\)x\(n\) upper-triangular adjacency matrix (where \(n\) in the data vector length) with value 1 if two units are neighbours or form a couple/pair, 0 otherwise.

Details

The adjacency matrix is a square matrix, with each row corresponding to a point/area, and with 1 values along the row marking the points/areas that are considered 'neighbours' or 'pairing/coupling'. In the context of spatial entropy, an adjacency matrix may take two roles. If Karlstrom and Ceccato's entropy is computed, the adjacency matrix identifies what areas are neighbours, i.e. what areas enter the computation of the local entropy of a specific area. If a spatial entropy based on the transformed variable \(Z\) is computed (see shannonZ for details on \(Z\)), the adjacency matrix identifies what pairs/couples of points/areas must be considered for the computation, according to the chosen distance range of interest.

Examples

Run this code

# NOT RUN {
dist.mat=euclid_dist(cbind(rep(1:5, each=5), rep(1:5,5)))
plot(cbind(rep(1:5, each=5), rep(1:5,5)))
adj_mat(dist.mat, dd1=dist.mat[1,2]) #for the contiguity matrix
adj_mat(dist.mat, 1, 3)

# }

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