ggraph: geom_edge_density – R documentation

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geom_edge_density

Show edges as a density map

Description

This geom makes it possible to add a layer showing edge presence as a density map. Each edge is converted to n points along the line and a jitter is applied. Based on this dataset a two-dimensional kernel density estimation is applied and plotted as a raster image. The density is mapped to the alpha level, making it possible to map a variable to the fill.

Usage

geom_edge_density(
  mapping = NULL,
  data = get_edges("short"),
  position = "identity",
  show.legend = NA,
  n = 100,
  ...
)

Arguments

`mapping`	Set of aesthetic mappings created by `ggplot2::aes()` or `ggplot2::aes_()`. By default x, y, xend, yend, group and circular are mapped to x, y, xend, yend, edge.id and circular in the edge data.
`data`	The return of a call to `get_edges()` or a data.frame giving edges in correct format (see details for for guidance on the format). See `get_edges()` for more details on edge extraction.
`position`	Position adjustment, either as a string, or the result of a call to a position adjustment function.
`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.
`n`	The number of points to estimate in the x and y direction, i.e. the resolution of the raster.
`...`	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.

Aesthetics

geom_edge_density understand the following aesthetics. Bold aesthetics are automatically set, but can be overridden.

x y xend yend edge_fill filter

Computed variables

x, y: The coordinates for each pixel in the raster
density: The density associated with the pixel

Edge aesthetic name expansion

In order to avoid excessive typing edge aesthetic names are automatically expanded. Because of this it is not necessary to write edge_colour within the aes() call as colour will automatically be renamed appropriately.

Author(s)

Thomas Lin Pedersen

Examples

require(tidygraph)
gr <- create_notable('bull') %>%
  activate(edges) %>%
  mutate(class = sample(letters[1:3], n(), replace = TRUE))

ggraph(gr, 'stress') +
  geom_edge_density(aes(fill = class)) +
  geom_edge_link() + geom_node_point()

ggraph

An Implementation of Grammar of Graphics for Graphs and Networks

v2.0.5

MIT + file LICENSE

Authors

Thomas Lin Pedersen [cre, aut] (<https://orcid.org/0000-0002-5147-4711>), RStudio [cph]

Initial release