How to change node and link colors in R googleVis sankey chart

Question

How can node and link colors be changed in R googleVis sankey chart? And link having the same color as its originating node?

library(googleVis)
datSK <- data.frame(From=c(rep("A",3), rep("B", 3)),
                To=c(rep(c("X", "Y", "Z"),2)),
                Weight=c(5,7,6,2,9,4))

Sankey <- gvisSankey(datSK, from="From", to="To", weight="Weight",
                 options=list(
                   sankey="{link: {color: { fill: '#d799ae' } },
                        node: { color: { fill: '#a61d4c' },
                        label: { color: '#871b47' } }}"))
plot(Sankey)

Answer 1

As soon as you have to color links from 2 originated nodes you'll need 2 colors for links. Also you have 5 nodes in total, so you'll need 5 colors for them.

Lets create 2 arrays in JSON format with colors for nodes and links

colors_link <- c('green', 'blue')
colors_link_array <- paste0("[", paste0("'", colors_link,"'", collapse = ','), "]")

colors_node <- c('yellow', 'lightblue', 'red', 'black', 'brown')
colors_node_array <- paste0("[", paste0("'", colors_node,"'", collapse = ','), "]")

Next, insert that array into options:

opts <- paste0("{
        link: { colorMode: 'source',
                colors: ", colors_link_array ," },
        node: { colors: ", colors_node_array ," }
      }" )

And, finally plot graph:

plot( gvisSankey(datSK, from="From", to="To", weight="Weight",
                     options=list(
                       sankey=opts)))

Note, that in options colorMode is set to 'source' which means you would like to color links from originated nodes. Alternatively, set 'target' to color links for destinated nodes

EDIT: add description for multilevel sankeys

It is a bit tricky to find how to assign colors for multilevel sankeys.

We need to create other dateframe:

datSK <- data.frame(From=c(rep("A",3), rep("B", 3), rep(c("X", "Y", "Z"), 2 )),
                To=c(rep(c("X", "Y", "Z"),2), rep("M", 3), rep("N", 3)),
                Weight=c(5,7,6,2,9,4,3,4,5,6, 4,8))

Here we have to change only arrays of colors. Command to built plot is the same Let's assume we want these colors for the nodes and links :

colors_link <- c('green', 'blue', 'yellow', 'brown', 'red')
colors_link_array <- paste0("[", paste0("'", colors_link,"'", collapse = ','), "]")

colors_node <- c('yellow', 'lightblue', 'red', 'black', 'brown', 'green', 'brown')
colors_node_array <- paste0("[", paste0("'", colors_node,"'", collapse = ','), "]")

Result would be :

The most trickiest part is to understand how these colors are assigned:

1. Links are assigned in the order they appear in dataset (row_wise)

2. For the nodes colors are assigned in the order plot is built.

   • From A to X, Y, Z - green
   • From X to M, N - blue
   • From Y to M, N - yellow
   • From Z to M, N - brown
   • From B to X, Y, Z - red

More detailed information on how to format sankey diagram : https://developers.google.com/chart/interactive/docs/gallery/sankey