利用igraph绘制网络图

igraph是一个简单易用，功能强大的网络数据处理框架，可以在R，Python, C语言中实现网络的可视化和数据挖掘，本文以R为例简单介绍其使用方法。

在Network中对应的数据结构为

1.图（graph）, 通常用大写字母G表示

2.顶点的英文为vertex, 用大写字母V表示

3.边的英文为edge, 用大写字母E表示。

下面以一个具体示例说明：

# 加载包
library(igraph)
library(RColorBrewer)

# 演示数据
links <- data.frame(
    source = c("A", "A", "A", "A", "A", "J", "B", "B", "C", "C", "D", "I"),
    target = c("B", "B", "C", "D", "J", "A", "E", "F", "G", "H", "I", "I"),
    importance = (sample(1:4, 12, replace = T))
)
nodes <- data.frame(name = LETTERS[1:10],
                    carac = c(rep("young", 3), rep("adult", 2), rep("old", 5)))

# 转换成igraph对象
network <-
    graph_from_data_frame(d = links,
                          vertices = nodes,
                          directed = F)

# 生成颜色向量
coul  <- brewer.pal(3, "Set1")
my_color <- coul[as.numeric(as.factor(V(network)$carac))]

# 绘图
plot(
    network,
    vertex.color = my_color,
    edge.width = E(network)$importance,
    vertex.size = E(network)$importance*12
)
# 添加图注
legend(
    "bottomright",
    legend = levels(as.factor(V(network)$carac)),
    col = coul ,
    bty = "n",
    pch = 20 ,
    pt.cex = 1,
    cex = 1,
    text.col = coul ,
    horiz = FALSE,
    inset = c(0.1, 0.1)
    )

如果我们希望生成可交互的图可以用tkplot

# 交互式网络图
tkplot(network,
    vertex.color = my_color,
    edge.width = E(network)$importance
)

同时我们也可以生成3D网络图：

# 3D网络图
rglplot(network,
    vertex.color = my_color,
    edge.width = E(network)$importance,
    vertex.size = c(E(network)$importance*12)
)

本次介绍就到这里了，其他更多请参考下方参考资料。

参考资料：

1.https://igraph.org/r/

2.https://www.r-graph-gallery.com/249-igraph-network-map-a-color.html