如何理解R語言做網(wǎng)絡(luò)圖的分析

1、一個(gè)包括一列數(shù)據(jù)的數(shù)據(jù)框，每一行是各個(gè)節(jié)點(diǎn)的名稱 

2、一個(gè)包含兩列數(shù)據(jù)的數(shù)據(jù)框，每一行代表節(jié)點(diǎn)節(jié)點(diǎn)之間的連線

> nodes<-data.frame(node=c("A","B","C","D"))
> edges<-data.frame(node1=c("A","A","A","B","B","C"),
+                   node2=c("B","C","D","C","D","D"))
> nodes
  node
1    A
2    B
3    C
4    D
> edges
  node1 node2
1     A     B
2     A     C
3     A     D
4     B     C
5     B     D
6     C     D
>

library(ggraph)
library(igraph)
net<-graph_from_data_frame(d=edges,vertices = nodes,directed = F)
ggraph(net)+
  geom_edge_link()+
  geom_node_point()

 

給節(jié)點(diǎn)添加一列分組信息，給每個(gè)節(jié)點(diǎn)一個(gè)數(shù)值，用來映射節(jié)點(diǎn)大小。

nodes$Group<-c("group_1","group_1","group_2","group_2")
nodes$Size<-c(5,15,10,18)
nodes$Name<-nodes$node

給每條邊添加顏色和粗細(xì)的映射數(shù)值

edges$color<-sample(seq(0,1,by=0.01),6)
edges$width<-sample(1:100,6)

net<-graph_from_data_frame(d=edges,vertices = nodes,directed = F)
ggraph(net)+
  geom_edge_link(aes(edge_width=width,edge_color=color))+
  geom_node_point(aes(size=Size,color=Group))+
  geom_node_text(aes(label=Name))

 

邊的漸變色深藍(lán)到淺藍(lán)不太好看，換！加上語句

scale_edge_color_continuous(low = "cyan",high = "red")

ggraph(net)+
  geom_edge_link(aes(edge_width=width,edge_color=color))+
  geom_node_point(aes(size=Size,color=Group))+
  geom_node_text(aes(label=Name))+
  scale_edge_color_continuous(low = "cyan",high = "red")

每個(gè)節(jié)點(diǎn)的點(diǎn)太小了，增大！加上語句

scale_size_area(max_size = 30)

ggraph(net)+
  geom_edge_link(aes(edge_width=width,edge_color=color))+
  geom_node_point(aes(size=Size,color=Group))+
  geom_node_text(aes(label=Name))+
  scale_edge_color_continuous(low = "cyan",high = "red")+
  scale_size_area(max_size = 30)

點(diǎn)的圖例太大了，占了其他圖例的位置，不要他了！加上語句

guides(size=F)

ggraph(net)+
  geom_edge_link(aes(edge_width=width,edge_color=color))+
  geom_node_point(aes(size=Size,color=Group))+
  geom_node_text(aes(label=Name))+
  scale_edge_color_continuous(low = "cyan",high = "red")+
  scale_size_area(max_size = 30)+
  guides(size=F)

 

這里遇到一個(gè)問題是：有沒有辦法改變圖例中點(diǎn)的大小呢？

新學(xué)到的：還可以改變圖例的前后順序，添加語句

guides(color=guide_legend(order=3))

ggraph(net)+
  geom_edge_link(aes(edge_width=width,edge_color=color))+
  geom_node_point(aes(size=Size,color=Group))+
  geom_node_text(aes(label=Name))+
  scale_edge_color_continuous(low = "cyan",high = "red")+
  scale_size_area(max_size = 30)+
  guides(size=F)+
  guides(color=guide_legend(order=3))

雖然點(diǎn)大小的圖例刪掉了，但是他應(yīng)該還是站著位置呢！如果想要把顏色圖例設(shè)置為最后可能得把order設(shè)置為4。 

有的節(jié)點(diǎn)超出了繪圖邊界，可以通過修改x和y軸的范圍來調(diào)整，加上命令

theme_bw()就可以顯示出坐標(biāo)軸的范圍

ggraph(net)+
  geom_edge_link(aes(edge_width=width,edge_color=color))+
  geom_node_point(aes(size=Size,color=Group))+
  geom_node_text(aes(label=Name))+
  scale_edge_color_continuous(low = "cyan",high = "red")+
  scale_size_area(max_size = 30)+
  guides(size=F)+
  guides(color=guide_legend(order=3))+
  theme_bw()+
  xlim(-0.8,0.8)+ylim(-0.8,0.8)