Graphics Reference
In-Depth Information
in the specified range. As in
Plotting a Function
,
we can improve the approximation by increas-
ing the number of interpolated values with
stat_function(n=200)
.
Creating a Network Graph
Problem
You want to create a network graph.
Solution
Use the igraph package. To create a graph, pass a vector containing pairs of items to
graph()
,
then plot the resulting object (
Figure 13-7
):
# May need to install first, with install.packages("igraph")
library(igraph)
# Specify edges for a directed graph
gd
<-
graph(c(
1
,
2
,
2
,
3
,
2
,
4
,
1
,
4
,
5
,
5
,
3
,
6
))
plot(gd)
# For an undirected graph
gu
<-
graph(c(
1
,
2
,
2
,
3
,
2
,
4
,
1
,
4
,
5
,
5
,
3
,
6
), directed
=
FALSE
FALSE
)
# No labels
plot(gu, vertex.label
=
NNA
)
