Problems 6

Problem 1

Create a CSV file for the adjacency matrix for the graph in Chapter 2, Problem 2 (Figure 2.5). Based on the adjacency matrix, produce a proximity matrix using the xGeodesicDistance() function. Visualize the data using non-metric MDS in R. How would you interpret the spatial proximity among the nodes in the resulting picture?

fn <- "C:/Users/Steve Borgatti/Documents/asnr/fig2p5.csv"

fig2p5 = as.matrix(read.csv(fn, stringsAsFactors=FALSE, row.names=1))

d = xGeodesicDistance(fig2p5)

fit <- isoMDS(d, k=2) # k is the number of dim

x <- fit$points[,1]

y <- fit$points[,2]

plot(x, y, xlab="Coordinate 1", ylab="Coordinate 2",

main="Nonmetric MDS", type="n")

text(x, y, labels = row.names(d), cex=.7)