Bipartite network graph with ggplot2

Question

I have the following data frame:

structure(list(X1 = structure(c(1L, 1L, 1L, 1L, 1L, 1L, 1L, 1L, 
2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 2L, 3L, 3L, 3L, 3L, 4L, 4L,         


        

Answer 1

A simple ggplot2 version of your graph is possible by using geom_segment() and transforming the data much like you did for the base graphics version. I've also included an arguably more polished version, using some of the more advanced customization options in ggplot2.

# Using ggplot2 version 0.9.2.1
library(ggplot2)

dat$x1_norm = rangeTransform(as.integer(dat$X1))
dat$x2_norm = rangeTransform(as.integer(dat$X2))

dat$y1 = 0
dat$y2 = 1

# Simple version.
p1 = ggplot(dat, aes(x=x1_norm, xend=x2_norm, y=y1, yend=y2, colour=X1)) +
     geom_segment(size=1.2) +
     scale_colour_brewer(palette="Set1", name="Person")

ggsave(plot=p1, filename="plot_1.png", height=3.5, width=6)

# Fancy version.
# Create separate data.frames to manually specify axis ticks and axis text.
axis_1 = data.frame(x=rangeTransform(as.integer(unique(dat$X1))),
                    y=0, label=as.character(unique(dat$X1)))

axis_2 = data.frame(x=rangeTransform(as.integer(unique(dat$X2))),
                    y=1, label=as.character(unique(dat$X2)))

p2 = ggplot(data=dat) +
     theme_bw() +
     theme(axis.title=element_blank()) +
     theme(axis.text=element_blank()) +
     theme(axis.ticks=element_blank()) +
     theme(panel.grid=element_blank()) +
     geom_segment(aes(x=x1_norm, xend=x2_norm, y=y1, yend=y2, colour=X1),
                  size=1.2) +
     geom_segment(x=0, xend=1, y=0, yend=0, size=0.7) +
     geom_segment(x=0, xend=1, y=1, yend=1, size=0.7) +
     scale_colour_brewer(palette="Set1", name="Person") +
     scale_y_continuous(limits=c(-0.2, 1.2), expand=c(0, 0)) +
     geom_segment(data=axis_1, aes(x=x, xend=x, y=y, yend=y-0.025), size=0.7) +
     geom_segment(data=axis_2, aes(x=x, xend=x, y=y, yend=y+0.025), size=0.7) +
     geom_text(data=axis_1, aes(label=label, x=x, y=y - 0.075)) +
     geom_text(data=axis_2, aes(label=label, x=x, y=y + 0.075))

ggsave(plot=p2, filename="plot_2.png", height=3.5, width=6)