How to sort source and/or target nodes in a sankey diagram within a shiny app?

Question

I have a simple sankey diagram, generated using networkD3 package inside a shiny app. How can source and/or target nodes be sorted?

As you can see in the MWE, by default, neither source nodes (A, B, C, D, E) nor target nodes (V, W, X, Y, Z) are sorted. At least, sorting is not comprehensible to me.

Code:

library("shiny")
library("networkD3")

ui <- fluidPage(
  column(3),
  column(6, sankeyNetworkOutput("mySankeyD")),
  column(3)
)

server <- function(input, output) {
  output$mySankeyD <- renderSankeyNetwork({
    myDf <- list(
      nodes=data.frame(name=c( "A", "B", "C", "D", "E",
                               "V", "W", "X", "Y", "Z")),
      links=data.frame(source=as.integer(c(0, 1, 2, 3, 3, 4, 4)),
                       target=as.integer(c(7, 6, 7, 8, 7, 5, 9)),
                       value =           c(1, 4, 1, 5, 1, 5, 3)
      )
    )

    sankeyNetwork(Links = myDf$links, Nodes = myDf$nodes, Source = "source",
                  Target = "target", Value = "value", NodeID = "name",
                  units = "TWh", fontSize = 25, nodeWidth = 30, fontFamily = "sans-serif", iterations = 30)
  })
}

shinyApp(ui, server)

How does sankeyNetwork() determine the order of nodes? Is it possible to sort them alphabetically?

I'd like to have sorted source nodes, if possible also sorted target nodes.

EDIT As @emilliman5 pointed out in the comment, it is no possible to sort the nodes manually.

Thus, are there other R packages out there to generate sankey diagrams that allow sorting of nodes? If yes, how to do so?

Thuja

I do not think you can manually set the vertical placement of the nodes. sankeyNetwork makes a call to D3.js and according to this post there is no way to set node position... – Pion

Ok. Thanks for the comment. Do you know of other tools/packages to produce such sankey diagrams in R? I will edit my question in this regard. – Thuja

the riverplot package lets you do this but the plot is not interactive. rCharts maybe able to do it as well with a little elbow grease. – Pion

Answer 1

Setting iterations = 0 inside sankeyNetwork() did the trick. Now nodes are plotted the same order as in the nodes dataframe.

library("networkD3")

myDf <- list(
    nodes=data.frame(name=c( "A", "B", "C", "D", "E",
                             "V", "W", "X", "Y", "Z")),
    links=data.frame(source=as.integer(c(0, 1, 2, 3, 3, 4, 4)),
                     target=as.integer(c(7, 6, 7, 8, 7, 5, 9)),
                     value =           c(1, 4, 1, 5, 1, 5, 3)
    )
)

sankeyNetwork(Links = myDf$links, Nodes = myDf$nodes, Source = "source",
              Target = "target", Value = "value", NodeID = "name",
              units = "TWh", fontSize = 25, nodeWidth = 30, 
              fontFamily = "sans-serif", iterations = 0)

Thuja