Getting started with RGraphSpace

In RGraphSpace: A Lightweight Interface Between 'igraph' and 'ggplot2' Graphics

knitr::opts_chunk$set(
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Package: RGraphSpace r packageVersion('RGraphSpace')

Overview

RGraphSpace is an R package that generates ggplot2 graphics for igraph objects [@Nepusz2006], scaling nodes and edges to a unit space. The package implements new ggplot2 geometric prototypes [@Wickham2016], optimized for representing large networks. This enables extensive customization of aesthetics and visual style, including colors, shapes, and line types. For extended documentation and use cases, see the online tutorials.

Quick start

This section will create a toy igraph object to demonstrate the basic RGraphSpace workflow. The input data is configured manually to ensure that users can easily view the basic graph attributes. We will use the igraph's make_star() function to create a simple star-like graph and then the V() and E() functions to set attributes for vertices and edges, respectively. RGraphSpace will require that all vertices have x, y, and name attributes.

#--- Load required packages
library("igraph")
library("ggplot2")
library("RGraphSpace")

# Make a 'toy' igraph with 5 nodes and 4 edges;
# ..either a directed or undirected graph
gtoy1 <- make_star(5, mode="out")

# Check whether the graph is directed or not
is_directed(gtoy1)
## [1] TRUE

# Check graph size
vcount(gtoy1)
## [1] 5
ecount(gtoy1)
## [1] 4

# Assign 'x' and 'y' coordinates to each vertex;
# ..this can be an arbitrary unit in (-Inf, +Inf)
V(gtoy1)$x <- c(0, 2, -2, -4, -8)
V(gtoy1)$y <- c(0, 0,  2, -4,  0)

# Assign a name to each vertex
V(gtoy1)$name <- paste0("n", 1:5)

# Plot the 'gtoy1' using standard R graphics
plot(gtoy1)

# Plot the 'gtoy1' using RGraphSpace
plotGraphSpace(gtoy1, add.labels = TRUE)

RGraphSpace attributes

Next, we list all vertex and edge attributes that can be passed to RGraphSpace methods.

Vertex attributes

# Node size (numeric in [0, 100], as '%' of the plot space)
V(gtoy1)$nodeSize <- c(8, 5, 5, 10, 5)

# Node shape (integer code between 0 and 25; see 'help(points)')
V(gtoy1)$nodeShape <- c(21, 22, 23, 24, 25)

# Node color (Hexadecimal or color name)
V(gtoy1)$nodeColor <- c("red", "#00ad39", "grey80", "lightblue", "cyan")

# Node line width (as in 'lwd' standard graphics; see 'help(gpar)')
V(gtoy1)$nodeLineWidth <- 1

# Node line color (Hexadecimal or color name)
V(gtoy1)$nodeLineColor <- "grey20"

# Node labels ('NA' will omit the label)
V(gtoy1)$nodeLabel <- c("V1", "V2", "V3", "V4", "V5")

# Node label size (in pts)
V(gtoy1)$nodeLabelSize <- 8

# Node label color (Hexadecimal or color name)
V(gtoy1)$nodeLabelColor <- "black"

# Node transparency (in [0,1])
V(gtoy1)$nodeAlpha <- 1

Edge attributes

Given a list of edges, RGraphSpace represents only one edge for each pair of connected vertices. If there are multiple edges connecting the same node pair, it will display the attributes of the first occurrence in the data.

# Edge width (as in 'lwd' standard graphics; see 'help(gpar)')
E(gtoy1)$edgeLineWidth <- 0.8

# Edge color (Hexadecimal or color name)
E(gtoy1)$edgeLineColor <- c("red","green","blue","black")

# Edge type (as in 'lty' standard graphics; see 'help(gpar)')
E(gtoy1)$edgeLineType <- c("solid", "11", "dashed", "2124")

# Edge transparency (in [0,1])
E(gtoy1)$edgeAlpha <- 1

Arrowhead attributes

Arrowhead in directed graphs: By default, an arrow will be drawn for each edge according to its left-to-right orientation in the edge list (e.g. A -> B). If there are mutual connections, the package will recode the mutual edges to represent a bidirectional flow.

# Arrowhead types in directed graphs
## Integer or character code:
## 0 = "---", 1 = "-->", -1 = "--|"
E(gtoy1)$arrowType <- 1

Arrowhead in undirected graphs: By default, no arrow will be drawn for undirected graphs. However, arrowheads may be assigned according to the coding below.

# Arrowhead types in undirected graphs
## Integer or character code:
##  0 = "---"
##  1 = "-->",  2 = "<--",  3 = "<->",  4 = "|->",
## -1 = "--|", -2 = "|--", -3 = "|-|", -4 = "<-|", 
E(gtoy1)$arrowType <- 1
# Note: in undirected graphs, this attribute overrides 
# the edge's orientation in the edge list

... and plot the updated igraph object. The most straightforward call simply passes an igraph directly to the wrapper plotGraphSpace() function.

# Plot the updated 'gtoy1' using RGraphSpace
plotGraphSpace(gtoy1, add.labels = TRUE)

# p <- plotGraphSpace(gtoy1, add.labels = TRUE)
# ggsave(filename = "./vignettes/cards/building_gspace.png", height=4, width=4,
#   units="in", device="png", dpi=200, plot = p)

Passing graphs to geoms

Alternatively, the igraph object can be transformed into a GraphSpace container and passed to the underlying geoms:

data('gtoy1', package = 'RGraphSpace')
gs <- GraphSpace(gtoy1)
gs <- normalizeGraphSpace(gs)
ggplot(gs) + 
  geom_edgespace() + 
  geom_nodespace() + 
  geom_text(aes(x = x, y = y, label = nodeLabel), size = 2) + 
  theme_gspace_coords(is_norm = TRUE)

Online tutorials

For detailed integration with the ggplot2 ecosystem, see the online documentation available at:

• https://sysbiolab.github.io/RGraphSpace/

Other examples

Vignettes illustrating how RGraphSpace can be used in combination with PathwaySpace to project network signals.

• https://sysbiolab.github.io/PathwaySpace/

Citation

If you use RGraphSpace, please cite:

• Sysbiolab Team. "RGraphSpace: A lightweight interface between igraph and ggplot2 graphics." R package, 2023. Doi: 10.32614/CRAN.package.RGraphSpace

Session information

sessionInfo()

References

RGraphSpace documentation built on June 13, 2026, 9:06 a.m.