气泡图沿着它们的底部边缘对齐 [英] Bubble Chart with bubbles aligned along their bottom edges

问题描述

有这样一个简单的方法，在R中制作气泡图：

Is there a simple way to make a bubble chart in R like this:

我玩过 ggplot 数据，并已获得了这么远：

I've played around with ggplot with fake data and have gotten this far:

cat<-c("A", "A", "B", "B", "C", "C")
chara<-c("1", "0", "1", "0", "1", "0")
percent<-c(80, 20, 60, 40, 90,10)
xcoord<-c(10,10,11,11,12,12)
ycoord<-c(10,10,10,10,10,10)

DF<-data.frame(cat,chara, percent, xcoord, ycoord)

NewBubbleChart <- ggplot(DF, aes(x = cat, y = "", size = percent, label = NULL, fill = chara), legend = FALSE) +
                    geom_point(color = "grey50", shape = 21, alpha = 0.99) +  
                   #geom_text(size=4) +
                    theme_bw() +
                    scale_size(range = c(5, 20))

NewBubbleChart <- NewBubbleChart +
                    scale_fill_manual(name = "Type",
                                      values = c("darkblue", "lightblue"),
                                      labels = c("0" = "Type 0", "1" = "Type 1"))

我最终不使用xcoord和ycoord部分，条形图也会工作，但是想要一个气泡图。

I ended up not using the xcoord and ycoord part, but I left it in. I know that a bar chart would work too, but a bubble chart is wanted instead.

推荐答案

这似乎很接近。

library(ggplot2)
# function to calculate coords of a circle
circle <- function(center,radius) {
  th <- seq(0,2*pi,len=200)
  data.frame(x=center[1]+radius*cos(th),y=center[2]+radius*sin(th))
}
# example dataset, similar to graphic
df <- data.frame(bank=paste("Bank",LETTERS[1:5]),start=1000*(5:1),end=500*(5:1))    
max <- max(df$start)
n.bubbles <- nrow(df)
scale <- 0.4/sum(sqrt(df$start))
# calculate scaled centers and radii of bubbles
radii <- scale*sqrt(df$start)
ctr.x <- cumsum(c(radii[1],head(radii,-1)+tail(radii,-1)+.01))
# starting (larger) bubbles
gg.1  <- do.call(rbind,lapply(1:n.bubbles,function(i)cbind(group=i,circle(c(ctr.x[i],radii[i]),radii[i]))))
text.1 <- data.frame(x=ctr.x,y=-0.05,label=paste(df$bank,df$start,sep="\n"))
# ending (smaller) bubbles
radii <- scale*sqrt(df$end)
gg.2  <- do.call(rbind,lapply(1:n.bubbles,function(i)cbind(group=i,circle(c(ctr.x[i],radii[i]),radii[i]))))
text.2 <- data.frame(x=ctr.x,y=2*radii+0.02,label=df$end)
# make the plot
ggplot()+
  geom_polygon(data=gg.1,aes(x,y,group=group),fill="dodgerblue")+
  geom_path(data=gg.1,aes(x,y,group=group),color="grey50")+
  geom_text(data=text.1,aes(x,y,label=label))+
  geom_polygon(data=gg.2,aes(x,y,group=group),fill="green2")+
  geom_path(data=gg.2,aes(x,y,group=group),color="grey50")+
  geom_text(data=text.2,aes(x,y,label=label), color="white")+
  labs(x="",y="")+scale_y_continuous(limits=c(-0.1,2.5*scale*sqrt(max(df$start))))+
  coord_fixed()+
  theme(axis.text=element_blank(),axis.ticks=element_blank(),panel.grid=element_blank())

泡沫泡沫图表，其表示两个事件或时间（经济崩溃之前和之后，图形中）的指标（图形中的银行市场资本化）的变化。为了使其工作，结束条件必须小于开始条件（否则内部气泡大于外部气泡）。

So this is a "bubble-in-bubble" chart, which represents the change in a metric (bank market capitalization in your graphic) between two events or times (before and after the economic collapse, in your graphic). In order for this to work the ending condition must be smaller than the starting condition (otherwise the "inner" bubble is larger than the outer bubble).

技巧位使圆圈沿着它们的底部边缘对准。这是真的很难使用 geom_point（...），所以我选择只画出气泡的圆圈。

The trick bit is getting the circles to be aligned along their bottom edges. This is really difficult using geom_point(...), so I chose to just draw circles for the bubbles instead.

我怀疑你在实际情况下必须手动调整文本的位置。如果你想要多行（如图所示），你可以考虑ggplot facets。

I suspect you'll have to tweak the positioning of the text a bit by hand in a real case. If you want multiple rows (as in the graphic), you might consider ggplot facets.

最后，如果你想要的圆圈阴影（例如用颜色渐变），这不是真正的ggplot旨在：这是可能的，但IMO的工作比它值得。

Finally, if you want the circles shaded (e.g. with a color gradient) this is not really what ggplot is intended for: it's possible but IMO much more work than it's worth.

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