Re: [igraph] How to Add Colorbar to Graph

[Matthew Walker]

Hi Lorenzo,

This might do your job.  For fine-tuning see ?legend

layout(matrix(c(1,2), 1,2), widths=c(3,1))

plot(g, layout=l,
    vertex.label.dist=0.5,   vertex.color=colbar[V(g)$time],
    vertex.frame.color="#ff000033",
edge.color="#55555533",vertex.label=NA, vertex.size=4
    )

d <- get.diameter(g,weights=NA)

V(g)$id <- seq(vcount(g))-1
g2 <- subgraph(g, d)
plot(g2, layout=l[ V(g2)$id+1, ],
vertex.color=colbar[V(g2)$time], vertex.frame.color="#ff000033",
  edge.color="#555555",vertex.label=NA, edge.width=2, vertex.size=4,
  add=TRUE, rescale=FALSE)



plot.new()

colours = unique(colbar[V(g)$time])
labels = paste("label", 1:length(colours))

legend("center",legend=labels, col=colours, pch=19,
      title="Title")


Cheers,

Matthew


Lorenzo Isella wrote:
> Dear All,
> Please consider the code snippet at the end of the email.
> It generates a network, highlights the diameter and paints each node 
> according to a discrete variable I call "time". 
> There are a few things I would like to add to the generated pdf
> (1) A colorbar, possible showing 8 discrete colors corresponding to the 
> 8 possible values of my "time" variable
> (2) I would like to be able to give a title to the colorbar
> (3) I would like to be able to write some text corresponding to each 
> color, to briefly explain what it stands for (I do not want to read 
> simply 1,2...8 for each value in "time")
> (4) I also need the possibility of fine-tuning the size of the text I 
> want to add to the plot, just to make sure it is readable in a figure 
> for a publication.
>
> Any help with (1)-(4) above is really appreciated.
> Cheers
>
> Lorenzo
>
>
>
>
> library(Cairo)
> library(igraph)
>
> set.seed(1234)
>
> g <- erdos.renyi.game(80, 1/20)
>
> n_col <- 8
>
> my_seq <- rep(seq(n_col),10)
>
> colbar <- rainbow(n_col)
>
> V(g)$time <- my_seq
>
> l <- layout.fruchterman.reingold(g)
> l <- layout.norm(l, -1,1, -1,1)
>
> CairoPDF("graph_with_colors.pdf")
>
> plot(g, layout=l,
>      vertex.label.dist=0.5,   vertex.color=colbar[V(g)$time],
>      vertex.frame.color="#ff000033", 
> edge.color="#55555533",vertex.label=NA, vertex.size=4
>      )
>
>
>
> d <- get.diameter(g,weights=NA)
>
> V(g)$id <- seq(vcount(g))-1
> g2 <- subgraph(g, d)
> plot(g2, layout=l[ V(g2)$id+1, ],
> vertex.color=colbar[V(g2)$time], vertex.frame.color="#ff000033",
>    edge.color="#555555",vertex.label=NA, edge.width=2, vertex.size=4,
>    add=TRUE, rescale=FALSE)
>
>
>
> dev.off()
>
>
>
>
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