Label the edges of a network.

All arguments to both geom_edgetext and geom_edgelabel are identical to those of geom_label, with the only difference that the label.size argument defaults to 0 in order to avoid drawing a border around the edge labels. The labels will be drawn at mid-edges. geom_text and geom_label produce strictly identical results.

geom_edgetext(
  mapping = NULL,
  data = NULL,
  position = "identity",
  parse = FALSE,
  ...,
  nudge_x = 0,
  nudge_y = 0,
  label.padding = unit(0.25, "lines"),
  label.r = unit(0.15, "lines"),
  label.size = 0,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

geom_edgelabel(
  mapping = NULL,
  data = NULL,
  position = "identity",
  parse = FALSE,
  ...,
  nudge_x = 0,
  nudge_y = 0,
  label.padding = unit(0.25, "lines"),
  label.r = unit(0.15, "lines"),
  label.size = 0,
  na.rm = FALSE,
  show.legend = NA,
  inherit.aes = TRUE
)

Arguments

mapping

Set of aesthetic mappings created by aes(). If specified and inherit.aes = TRUE (the default), it is combined with the default mapping at the top level of the plot. You must supply mapping if there is no plot mapping.

data

The data to be displayed in this layer. There are three options:

If NULL, the default, the data is inherited from the plot data as specified in the call to ggplot().

A data.frame, or other object, will override the plot data. All objects will be fortified to produce a data frame. See fortify() for which variables will be created.

A function will be called with a single argument, the plot data. The return value must be a data.frame, and will be used as the layer data. A function can be created from a formula (e.g. ~ head(.x, 10)).

position

Position adjustment, either as a string, or the result of a call to a position adjustment function. Cannot be jointly specified with nudge_x or nudge_y.

parse

If TRUE, the labels will be parsed into expressions and displayed as described in ?plotmath.

...

Other arguments passed on to layer(). These are often aesthetics, used to set an aesthetic to a fixed value, like colour = "red" or size = 3. They may also be parameters to the paired geom/stat.

nudge_x, nudge_y

Horizontal and vertical adjustment to nudge labels by. Useful for offsetting text from points, particularly on discrete scales. Cannot be jointly specified with position.

label.padding

Amount of padding around label. Defaults to 0.25 lines.

label.r

Radius of rounded corners. Defaults to 0.15 lines.

label.size

Size of label border, in mm.

na.rm

If FALSE, the default, missing values are removed with a warning. If TRUE, missing values are silently removed.

show.legend

logical. Should this layer be included in the legends? NA, the default, includes if any aesthetics are mapped. FALSE never includes, and TRUE always includes. It can also be a named logical vector to finely select the aesthetics to display.

inherit.aes

If FALSE, overrides the default aesthetics, rather than combining with them. This is most useful for helper functions that define both data and aesthetics and shouldn't inherit behaviour from the default plot specification, e.g. borders().

Examples

if (require(network) && require(sna)) {
  data(flo, package = "network")
  n <- network(flo, directed = FALSE)

  # arbitrary categorical edge attribute
  e <- sample(letters[ 1:4 ], network.edgecount(n), replace = TRUE)
  set.edge.attribute(n, "type", e)

  # with labelled edges
  ggplot(n, aes(x, y, xend = xend, yend = yend)) +
    geom_edges(aes(colour = type)) +
    geom_edgetext(aes(label = type, colour = type)) +
    geom_nodes(size = 4, colour = "grey50") +
    theme_blank()

  # label only a subset of all edges with arbitrary symbol
  edge_type <- function(x) {
    x[ x$type == "a", ]
  }
  ggplot(n, aes(x, y, xend = xend, yend = yend)) +
    geom_edges() +
    geom_edgetext(label = "=", data = edge_type) +
    geom_nodes(size = 4, colour = "grey50") +
    theme_blank()
}