I have a network that is connected like the following:
library(igraph)
network <- graph_from_literal(1--2,2--3,3--4,4--5,3--6,6--7,3--8,8--9)
and have the distance between each segment
> data=data.frame(Origin=c(1,2,3,4,3,6,3,8), Destination=c(2,3,4,5,6,7,8,9), km=c(0.3,0.5,0.2,0.1,1,2,0.6,0.4))
> data
Origin Destination km
1 2 0.3
2 3 0.5
3 4 0.2
4 5 0.1
3 6 1.0
6 7 2.0
3 8 0.6
8 9 0.4
I would like to find the distance matrix between all points and I tried using
distMatrix <- shortest.paths(data, v=Origin(data), to=Destination(data))
but cannot make it work.
Thanks!
The distances() function will give you a distance matrix. By setting the edge weights, the distance matrix will include these weights in the calculation. In the code below, I create the graph from your dataset data, such that the edges are correctly ordered:
library("igraph")
data = data.frame(Origin=c(1,2,3,4,3,6,3,8), Destination=c(2,3,4,5,6,7,8,9),
km=c(0.3,0.5,0.2,0.1,1,2,0.6,0.4))
g = graph_from_edgelist(cbind(data$Origin, data$Destination))
E(g)
#> + 8/8 edges from 7ad6d28:
#> [1] 1->2 2->3 3->4 4->5 3->6 6->7 3->8 8->9
E(g)$weight = data$km
distances(g)
#> [,1] [,2] [,3] [,4] [,5] [,6] [,7] [,8] [,9]
#> [1,] 0.0 0.3 0.8 1.0 1.1 1.8 3.8 1.4 1.8
#> [2,] 0.3 0.0 0.5 0.7 0.8 1.5 3.5 1.1 1.5
#> [3,] 0.8 0.5 0.0 0.2 0.3 1.0 3.0 0.6 1.0
#> [4,] 1.0 0.7 0.2 0.0 0.1 1.2 3.2 0.8 1.2
#> [5,] 1.1 0.8 0.3 0.1 0.0 1.3 3.3 0.9 1.3
#> [6,] 1.8 1.5 1.0 1.2 1.3 0.0 2.0 1.6 2.0
#> [7,] 3.8 3.5 3.0 3.2 3.3 2.0 0.0 3.6 4.0
#> [8,] 1.4 1.1 0.6 0.8 0.9 1.6 3.6 0.0 0.4
#> [9,] 1.8 1.5 1.0 1.2 1.3 2.0 4.0 0.4 0.0
Created on 2021-09-06 by the reprex package (v2.0.1)