Examples pulled from **Network Visualization with R**, [Polnet 2016](http://www.kateto.net/polnet2016) by Katya Ognyanova. ```{r} suppressPackageStartupMessages({ library(RColorBrewer) library(readr) library(dplyr) library(igraph) }) ``` ```{r} data_dir <- "Data files" ``` For igraph plotting parameters, node options start with `vertex.` and edge options start with `edge.`. Get options with ```{r eval=FALSE} ?igraph.plotting ``` Set node & edge options in two ways: 1. specify them in `plot()` function 2. add them to the `igraph` object ### igraph with Dataset 2 ```{r} nodes2 <- read_csv(file.path(data_dir, "Dataset2-Media-User-Example-NODES.csv")) ## First row is names, so need to use read.csv. links2 <- read.csv(file.path(data_dir, "Dataset2-Media-User-Example-EDGES.csv"), header = TRUE, row.names = 1) ``` Create a igraph network object from the two-mode matrix: ```{r} net2 <- graph_from_incidence_matrix(links2) ``` Built-in vertex attribute 'type' shows which mode vertices belong to. ```{r} table(V(net2)$type) ``` ```{r} plot(net2,vertex.label=NA) ``` To transform a one-mode network matrix into an igraph object, use `graph_from_adjacency_matrix()`. ### Identify Media Outlets and Users Modify network object visual properties -- color, size and shape. Media outlets are squares; users are circles. ```{r} # Media outlets are blue squares, audience nodes are orange circles: V(net2)$color <- c("steel blue", "orange")[V(net2)$type+1] V(net2)$shape <- c("square", "circle")[V(net2)$type+1] # Media outlets will have name labels, audience members will not: V(net2)$label <- "" V(net2)$label[V(net2)$type==F] <- nodes2$media[V(net2)$type==F] V(net2)$label.cex=.6 V(net2)$label.font=2 plot(net2, vertex.label.color="white", vertex.size=(2-V(net2)$type)*8) ``` Text only for nodes. ```{r} plot(net2, vertex.shape = "none", vertex.label = nodes2$media, vertex.label.color = V(net2)$color, vertex.label.font = 2, vertex.label.cex = .6, edge.color = "gray70", edge.width = 2) ``` ### Generate bipartite projections Calculate co-memberships by multiplying the network matrix by its transpose, or using `bipartite.projection()`. ```{r} (net2.bp <- bipartite.projection(net2)) ``` ```{r} par(mfrow=c(1,2)) vtype <- c("media","users")[1 + is.na(nodes2$media.type)] plot(net2.bp$proj1, vertex.label.color = "black", vertex.label.dist = 1, vertex.label = nodes2$media[vtype == "media"]) plot(net2.bp$proj2, vertex.label.color = "black", vertex.label.dist = 1, vertex.label = nodes2$media[vtype == "users"]) ``` Now force layout to be the same and drop shapes. ```{r} par(mfrow=c(1,2)) lay <- layout_with_fr(net2) plot(net2.bp$proj1, vertex.shape = "none", vertex.label.color = "black", vertex.label.dist = 1, vertex.label = nodes2$media[vtype == "media"], layout = lay[vtype == "media",]) plot(net2.bp$proj2, vertex.shape = "none", vertex.label.color = "red", vertex.label.dist = 1, vertex.label = nodes2$media[vtype == "users"], layout = lay[vtype == "users",]) ```