使用ggplot将geom_label放置在网络外部吗? [英] Position geom_label on the outside of a network using ggplot?

问题描述

我正在使用 ggnet 和 ggplot 创建网络样式图.目前，我只是使用 geom_label 的 nudge_y 参数来放置标签.但是我想知道是否可以放置标签，使它们始终位于圆的外部(我的网络始终是圆形的).一个玩具示例如下所示.

I am creating a network style plot using ggnet and ggplot. At the moment im just using geom_label's nudge_y argument to position the labels. But I was wondering if it's possible to position the labels so they are always on the outside of the circle (my network is always circular). A toy example is shown below.

library(ggplot2)
library(igraph)
library(GGally) # contains ggnet2

nam <- c("A", "B", "C", "D", "E") # Node name

g <- sample_pa(5, m = 5)  # generate graph with x nodes
g <- igraph::as_data_frame(g) # create df
g <- rbind(g$to,g$from) # create matrix


net.bg <- make_graph(g, 5, directed = FALSE) #make graph
E(net.bg)$weight <- sample(1:3, 5,replace=T)
V(net.bg)$size   <- sample(1:5, 5,replace=T)


p <- ggnet2(net.bg, 
            mode = "circle",  
            size = V(net.bg)$size,
            node.color = "red",
            edge.size = E(net.bg)$weight,
            edge.alpha = 0.5,
            edge.color = "blue") +
  theme(legend.text = element_text(size = 10)) +
  geom_label(aes(label = nam),nudge_y = 0.05)

p

上面的代码产生如下内容:

The above code produces something like this:

可以看出，所有标签都在y方向上微移.但是我希望做这样的事情(我在PowerPoint中制作):

As can be seen, the labels are all nudged in the y direction. But I was hoping to make something like this (which I made in powerpoint):

有可能做这样的事情吗?

Is it possible to do such a thing?

推荐答案

这是可能的，尽管不是特别容易或便携.对象 p 是ggplot对象，因此包含在坐标，几何，映射，数据等方面构建图所需的所有信息.

It is possible, though not particularly easy or portable. The object p is a ggplot object, so contains all the information required to build the plot in terms of co-ordinates, geoms, mapping, data, etc.

这意味着您可以直接更改 labels 图层，以便其x，y坐标比其先前值小一倍.因此，您可以这样做:

This means you can directly change the labels layer so that its x, y co-ordinates are a small multiple above their previous values. So you could do:

geoms <- sapply(p$layers, function(x) class(x$geom)[1])
segments <-  p$layers[[which(geoms == "GeomSegment")]] 
labels <-  p$layers[[which(geoms == "GeomLabel")]] 
segments$data <- segments$data - 0.5
p$data$x <- p$data$x - 0.5
p$data$y <- p$data$y - 0.5
labels$position$y <- 0
labels$data <- p$data
labels$data$x <- labels$data$x * 1.1
labels$data$y <- labels$data$y * 1.1
p$scales$scales <- lapply(p$scales$scales, function(x) {
  if(class(x)[1] == "ScaleContinuousPosition") ScaleContinuousPosition else x })
p <- p + theme(axis.text = element_blank())

p

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