Plotting texts as graphs with R and igraph

I’ve plotted several word association graphs for this New York Times article (1st paragraph) using R and the igraph library.

#1, random method

#2, circle method

#3, sphere method

#4, spring method

#5, fruchterman-reingold method

# 6, kamada-kawai method

#7, graphopt method

The red vertices mark cliques. Here’s the (rough) R code for plotting such graphs:

rm(list=ls()); library("igraph"); library("Cairo"); # read parameters print("Text-as-Graph for R 0.1"); print("------------------------------------"); print("Path (no trailing slash): "); datafolder <- scan(file="", what="char"); print("Text file: "); datafile <- scan(file="", what="char"); txt <- scan(paste(datafolder, datafile, sep="/"), what="char", sep="\n", encoding="UTF-8"); print("Width/Height (e.g. 1024x768): "); res <- scan(file="", what="char"); rwidth <- unlist(strsplit(res, "x"))[1] rheight <- unlist(strsplit(res, "x"))[2] words <- unlist(strsplit(gsub("[[:punct:]]", " ", tolower(txt)), "[[:space:]]+")); g.start <- 1; g.end <- length(words) - 1; assocs <- matrix(nrow=g.end, ncol=2) for (i in g.start:g.end) { assocs[i,1] <- words[i]; assocs[i,2] <- words[i+1]; print(paste("Pass #", i, " of ", g.end, ". ", "Node word is ", toupper(words[i]), ".", sep="")); } print("Build graph from data frame..."); g.assocs <- graph.data.frame(assocs, directed=F); print("Label vertices..."); V(g.assocs)$label <- V(g.assocs)$name; print("Associate colors..."); V(g.assocs)$color <- "Gray"; print("Find cliques..."); V(g.assocs)[unlist(largest.cliques(g.assocs))]$color <- "Red"; print("Plotting random graph..."); CairoPNG(paste(datafolder, "/", "text-igraph-random.png", sep=""), width=as.numeric(rwidth), height=as.numeric(rheight)); plot(g.assocs, layout=layout.random, vertex.size=4, vertex.label.dist=0); dev.off(); print("Plotting circle graph..."); CairoPNG(paste(datafolder, "/", "text-igraph-circle.png", sep=""), width=as.numeric(rwidth), height=as.numeric(rheight)); plot(g.assocs, layout=layout.circle, vertex.size=4, vertex.label.dist=0); dev.off(); print("Plotting sphere graph..."); CairoPNG(paste(datafolder, "/", "text-igraph-sphere.png", sep=""), width=as.numeric(rwidth), height=as.numeric(rheight)); plot(g.assocs, layout=layout.sphere, vertex.size=4, vertex.label.dist=0); dev.off(); print("Plotting spring graph..."); CairoPNG(paste(datafolder, "/", "text-igraph-spring.png", sep=""), width=as.numeric(rwidth), height=as.numeric(rheight)); plot(g.assocs, layout=layout.spring, vertex.size=4, vertex.label.dist=0); dev.off(); print("Plotting fruchterman-reingold graph..."); CairoPNG(paste(datafolder, "/", "text-igraph-fruchterman-reingold.png", sep=""), width=as.numeric(rwidth), height=as.numeric(rheight)); plot(g.assocs, layout=layout.fruchterman.reingold, vertex.size=4, vertex.label.dist=0); dev.off(); print("Plotting kamada-kawai graph..."); CairoPNG(paste(datafolder, "/", "text-igraph-kamada-kawai.png", sep=""), width=as.numeric(rwidth), height=as.numeric(rheight)); plot(g.assocs, layout=layout.kamada.kawai, vertex.size=4, vertex.label.dist=0); dev.off(); #CairoPNG(paste(datafolder, "/", "text-igraph-reingold-tilford.png", sep=""), width=as.numeric(rwidth), height=as.numeric(rheight)); #plot(g.assocs, layout=layout.reingold.tilford, vertex.size=4, vertex.label.dist=0); #dev.off(); print("Plotting graphopt graph..."); CairoPNG(paste(datafolder, "/", "text-igraph-graphopt.png", sep=""), width=as.numeric(rwidth), height=as.numeric(rheight)); plot(g.assocs, layout=layout.graphopt, vertex.size=4, vertex.label.dist=0); dev.off(); print("Done!");