R当中的坐标中断一般都使用plotrix库中的axis.break(), gap.plot(), gap.barplot(), gap.boxplot()等几个函数来实现，例：
gap plot
> library(plotrix) > opar<-par(mfrow=c(3,2)) > plot(sample(5:7,20,replace=T),main="Axis break test",ylim=c(2,8)) > axis.break(axis=2,breakpos=2.5,style="gap") > axis.break(axis=2,breakpos=3.5,style="slash") > axis.break(axis=2,breakpos=4.5,style="zigzag") > twogrp<-c(rnorm(5)+4,rnorm(5)+20,rnorm(5)+5,rnorm(5)+22) > gap.plot(twogrp,gap=c(8,16,25,35), + xlab="X values",ylab="Y values",xlim=c(1,30),ylim=c(0,25), + main="Test two gap plot with the lot",xtics=seq(0,30,by=5), + ytics=c(4,6,18,20,22,38,40,42), + lty=c(rep(1,10),rep(2,10)), + pch=c(rep(2,10),rep(3,10)), + col=c(rep(2,10),rep(3,10)), + type="b") > gap.plot(21:30,rnorm(10)+40,gap=c(8,16,25,35),add=TRUE, + lty=rep(3,10),col=rep(4,10),type="l") > gap.barplot(twogrp,gap=c(8,16),xlab="Index",ytics=c(3,6,17,20), + ylab="Group values",main="Barplot with gap") > gap.barplot(twogrp,gap=c(8,16),xlab="Index",ytics=c(3,6,17,20), + ylab="Group values",horiz=TRUE,main="Horizontal barplot with gap") > twovec<-list(vec1=c(rnorm(30),-6),vec2=c(sample(1:10,40,TRUE),20)) > gap.boxplot(twovec,gap=list(top=c(12,18),bottom=c(-5,-3)), + main="Show outliers separately") > gap.boxplot(twovec,gap=list(top=c(12,18),bottom=c(-5,-3)),range=0, + main="Include outliers in whiskers") > par(opar) |
从图像效果上来看，这样的坐标中断只能说实现了坐标中断，但效果上是非常一般的。甚至远不如excel, openoffice当中出图效果好。为此，我们需要对plotrix库中的gap.plot做出修改，以达到满意的效果。
最简单的修改办法就是在使用了gap.plot, gap.barplot, gap.boxplot之后重新使用axis.break来修改中断类型，使得看上去美一点。
> axis.break(2,from,breakcol="snow",style="gap") > axis.break(2,from*(1+0.02),breakcol="black",style="slash") > axis.break(4,from*(1+0.02),breakcol="black",style="slash") > axis(2,at=from) |
使用上面的办法可以绘制出双反斜线中断，并可以视实际情况加油断点起止位置。
改进的gap.plot
> library(plotrix) > x<-c(1:5,6.9,7) > y<-2^x > from<-33 > to<-110 > opar<-par(mfrow=c(2,2)) > plot(x,y,type="b",main="normal plot") > gap.plot(x,y,gap=c(from,to),type="b",main="gap plot") > axis.break(2,from,breakcol="snow",style="gap") > axis.break(2,from*(1+0.02),breakcol="black",style="slash") > axis.break(4,from*(1+0.02),breakcol="black",style="slash") > axis(2,at=from) > gap.barplot(y,gap=c(from,to),col=as.numeric(x),main="barplot with gap") > axis.break(2,from,breakcol="snow",style="gap") > axis.break(2,from*(1+0.02),breakcol="black",style="slash") > axis.break(4,from*(1+0.02),breakcol="black",style="slash") > axis(2,at=from) > gap.barplot(y,gap=c(from,to),col=as.numeric(x),horiz=T,main="Horizontal barplot with gap") > axis.break(1,from,breakcol="snow",style="gap") > axis.break(1,from*(1+0.02),breakcol="black",style="slash") > axis.break(3,from*(1+0.02),breakcol="black",style="slash") > axis(1,at=from) > par(opar) |