調準多個圖軸中的R

Question

我在R中的以下情節包含堆疊在彼此的頂部兩個曲線圖：

time <- seq(0,72,12) 
betagal.abs <- c(0.05,0.18,0.25,0.31,0.32,0.34,0.35) 
cell.density <- c(0,1000,2000,3000,4000,5000,6000) 

layout(matrix(c(1,2,2), 3, 1, byrow=TRUE)) 

par(mar=c(1, 4, 4, 6) + 0.1) 
othertime <- seq(0,48,12) 
otherbetagal <- c(0.05,0.18,0.25,0.31,0.32) 
plot(othertime, 
    otherbetagal+c(0.13072000, -0.38438639, 0.16157348, 
        -0.07862935, 1.72706526), 
    xlim=c(0,70)) 

## add extra space to right margin of plot within frame 
par(mar=c(5, 4, 4, 6) + 0.1) 

## Plot first set of data and draw its axis 
plot(time, betagal.abs, pch=16, axes=FALSE, xlab="", ylab="", 
    xlim=c(0,70), 
    type="b",col="black", main="Mike's test data") 
axis(2, col="black",las=1) ## las=1 makes horizontal labels 
mtext("Beta Gal Absorbance",side=2,line=2.5) 
box() 

## Allow a second plot on the same graph 
par(new=TRUE) 

## Plot the second plot and put axis scale on right 
plot(time, cell.density, pch=15, xlab="", ylab="", 
    axes=FALSE, type="b", col="red") 
## a little farther out (line=4) to make room for labels 
mtext("Cell Density",side=4,col="red",line=4) 
axis(4, col="red",col.axis="red",las=1) 

## Draw the time axis 
axis(1,pretty(range(time),10)) 
mtext("Time (Hours)",side=1,col="black",line=2.5) 

不幸頂端x軸和底部x軸不對齊。我希望他們一致。如果仔細觀察，刻度線會接近但不對齊 - 即，您無法從頂部繪圖中的「70」勾出直線畫出垂直線，在底部繪圖中勾選「70」。如何解決？

Answer 1

如果在同一XLIM參數添加到第二幅圖中，x軸將對齊......

## Plot the second plot and put axis scale on right 
plot(time, cell.density, pch=15, xlab="", ylab="", 
    xlim=c(0,70),# same parameter as the first plot 
    axes=FALSE, type="b", col="red")