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plot ggraph using supplied node coordinates

As the title says. I have a graph object created using igraph::sample_grg(), which I want to plot using ggraph, with nodes positioned according to the node attributes x and y. What I have tried:

Create graph:

set.seed(1234)

library(igraph)
library(ggraph)
library(tidygraph)

g <- sample_grg(5, 0.4, torus = FALSE, coords = TRUE)

The graph comes with x and y attributes which should be the node positions

vertex.attributes(g)
$x
[1] 0.009495756 0.113703411 0.609274733 0.666083758 0.860915384    
$y
[1] 0.6222994 0.6233794 0.6403106 0.2325505 0.5142511

Attempt 1

ggraph(g) +
  geom_edge_link() +
  geom_node_point()

Error in graph_to_tree(graph, mode = direction) : Graph must be directed

I don't have or want a directed graph.

Attempt 2

l1 = data.frame(x = V(g)$x, y = V(g)$y)

ggraph(g, layout = l1) +
  geom_edge_link() +
  geom_node_point()

Error: `data` must be uniquely named but has duplicate columns
Run `rlang::last_error()` to see where the error occurred.

Attempt 3

l2 <- create_layout(g, layout = l1) 
l2 <- l2[,-c(1:2)]

ggraph(l2, layout = l2) +
  geom_edge_link() +
  geom_node_point()

Error in .register_graph_context(attr(plot$data, "graph"), free = TRUE) : 
  is.tbl_graph(graph) is not TRUE

Attempt 4

g2 <- as_tbl_graph(g)

ggraph(g2, layout = "manual") +
  geom_edge_link() +
  geom_node_point()

Error in eval_tidy(x, .N()) : object '' not found

Attempt 5 following this question:

ggraph(g, layout = "manual", circular = FALSE, node.positions = l1) +
  geom_edge_link() + 
  geom_node_point()

Error in layout_fun(graph, circular = circular, ...) : 
  unused argument (node.positions = list(c(0.0612166156060994, 0.0649281670339406, 0.250601968728006, 0.726055516628549, 0.916498943232), c(0.979841426480561, 0.450912220636383, 0.283102283952758, 0.782102265860885, 0.663251199992374)))

I feel like I am missing something really obvious, any advice would be much appreciated.

Solution

  • Since you have enabled coords = TRUE when generating g, the layout coordinates names have been given as x and y.

    To avoid collision, you should name layout l1 with different column names, e.g., lx or ly,

    l1 <- data.frame(lx = NA, ly = NA)

ggraph(g, l1) +
  geom_edge_link() +
  geom_node_point()

    enter image description here

    If you disable coords = , i.e.,

    g <- sample_grg(5, 0.4, torus = FALSE, coords = FALSE)

    then you can provide your own coordinates with column names x and y (since no such columns will be produce if you don't specify their values), e.g.,

    l1 <- data.frame(x = 1:5, y = 5:1)

ggraph(g, l1) +
  geom_edge_link() +
  geom_node_point()

    and you will see

    enter image description here