Order of treechart entries not correct in R igraph package

Question

This is a follow-up question from : Creating treechart from tabbed text in R

I am using following function:

treechart = function(){
library(psych)
fiel         


        

Answer 1

It's not that the layout is incorrect, it's just that you asked for the layout.reingold.tilford layout and that's what you got. As you can see, it likes to move more complex branches to one side. It does not consider the order that the vertices were specified. I tried writing a new layout function that would preserve order

layout.tree.order <- function(g, vseq=V(g)$name, root=vseq[1]) {
    leaves <- vseq[sapply(V(g)[vseq], function(x) 
        length(unique(neighbors(g, x, mode="out"))))==0]
    ypos <- rep(NA, vcount(g))
    ypos[match(leaves, V(g)$name)]<-rev(seq(0,1,length.out=length(leaves)))

    calcypos<-function(g, vx) {
        if (!is.na(ypos[vx])) {
            p <- ypos[vx]
        } else {
            nb <- unique(neighbors(g, V(g)[vx]))
            p <- mean(sapply(nb, function(x) calcypos(g,x)))
        }
        ypos[vx] <<- p
        return(invisible(p))
    }
    calcypos(g, which(V(g)$name == root))
    xpos <- c(shortest.paths(g, V(g)[which(vseq == root)], V(g), mode="out"))

    cbind(xpos, ypos)
}

Then you just want to change the plot line in your treemap function to add one additional line and change the layout

vseq <- apply(dat, 1, function(x) na.omit(rev(x))[1])
plot.igraph(g, vertex.size=0, edge.arrow.size=0, 
    layout=layout.tree.order(g, vseq))

So the vseq here is what specifies the top-down ordering. Here we use the values in the order that they appear in your dat data frame. This will produce the following plot