Color edges according to edge attribute in visNetwork

Question

I'm trying to color edges in a graph according to an edge attribute using visNetwork, but they keep coming out the same color as the nodes. What am I doing wrong?

Code:

edges$color <- edges$agreement_num

visNetwork(nodes, edges) %>%
  visEdges(arrows = 'from', smooth =T)  %>%
  visOptions(selectedBy= "com") %>%
  visNodes(label = TRUE,scaling = list(label = list(min = 30, max = 50))) %>%
  visIgraphLayout(layout = "layout_nicely") %>%

Reproducible example:

nodes <- structure(list(id = c("United States of America", "Canada", "Mexico", 
"Peru", "Colombia", "Honduras", "Guatemala", "Nicaragua", "Nigeria", 
"Belize"), com = c("5", "5", "5", "5", "5", "5", "5", "5", "5", 
"5"), label = c("United States of America", "Canada", "Mexico", 
"Peru", "Colombia", "Honduras", "Guatemala", "Nicaragua", "Nigeria", 
"Belize"), font.size = c(30, 30, 30, 30, 30, 30, 30, 30, 30, 
30), group = c("5", "5", "5", "5", "5", "5", "5", "5", "5", "5"
)), row.names = c("United States of America", "Canada", "Mexico", 
"Peru", "Colombia", "Honduras", "Guatemala", "Nicaragua", "Nigeria", 
"Belize"), class = "data.frame")

edges <- structure(list(from = c("Canada", "Canada", "United States of America", 
"Mexico", "United States of America", "Mexico", "United States of America", 
"Canada", "Mexico", "United States of America"), to = c("Antigua and Barbuda", 
"Barbados", "Barbados", "Belize", "Belize", "Canada", "Canada", 
"China, Taiwan Province of", "China, Taiwan Province of", "China, Taiwan Province of"
), weight = c(171966510.34557, 3894809879.52684, 190168793161.723, 
229417909.693992, 56692662824.8982, 713710750.313289, 6240520849382.04, 
286476683134.553, 928907970.889569, 14741754565243.3), agreement_num = c(1, 
3, 45, 32, 2, 185L, NA, 3, 6, 45), value = c(171966510.34557, 
3894809879.52684, 190168793161.723, 229417909.693992, 56692662824.8982, 
713710750.313289, 6240520849382.04, 286476683134.553, 928907970.889569, 
14741754565243.3)), row.names = c(NA, 10L), class = "data.frame")

Answer 1

You need to assign R colour names, hex values, or a combination of both to your color column. You can do this manually, or by using the palette() function. Here's how to do it manually:

library(visNetwork)

# Determine number of colours required and check for NAs
unique(edges$agreement_num)
# [1]   1   3  45  32   2 185  NA   6

# Create df of colours assigned to unique agreement_num values
colourdf <- data.frame(agreement_num = unique(edges$agreement_num),
                       color = c("#004949", "#009292", "#ff6db6", "#ffb6db",
                                 "#490092", "#006ddb", NA, "#6db6ff"))

# Join dfs
edges <- merge(edges, colourdf, by = "agreement_num", all.x = TRUE)

visNetwork(nodes, edges) %>%
  visEdges(arrows = 'from', smooth = T)  %>%
  visOptions(selectedBy = "com") %>%
  visNodes(label = TRUE,scaling = list(label = list(min = 30, max = 50))) %>%
  visIgraphLayout(layout = "layout_nicely")

Screencap of result: