在轮廓图中控制z标签 [英] Controlling z labels in contourplot

问题描述

我试图控制应使用点阵库中的 contourplot()绘制的轮廓图中应写入多少z个标签.
我有30条轮廓线，但我只想标记前5条轮廓线.我尝试了很多类似的事情

I am trying to control how many z labels should be written in my contour plot plotted with contourplot() from the lattice library.
I have 30 contour lines but I only want the first 5 to be labelled. I tried a bunch of things like

contourplot(z ~ z+y, data=d3, cuts=30, font=3, xlab="x axis", ylab="y axis", scales=list(at=seq(2,10,by=2)))
contourplot(z ~ z+y, data=d3, cuts=30, font=3, xlab="x axis", ylab="y axis", at=seq(2,10,by=2))

但没有任何效果.

还可以在同一张图上绘制两个 contourplot()吗?我尝试过

Also, is it possible to plot two contourplot() on the same graph? I tried

contourplot(z ~ z+y, data=d3, cuts=30)
par(new=T)
contourplot(z ~ z+y, data=d3, cuts=20)

但是它不起作用.
谢谢！

but it's not working.
Thanks!

推荐答案

您可以指定 labels 作为字符向量参数，并使用rep("，5)设置最后一个值，所以也许对于您在先前有关轮廓的问题中提供的示例

You can specify the labels as a character vector argument and set the last values with rep("", 5), so perhaps for the example you offered on an earlier question about contour

 x = seq(0, 10, by = 0.5)
 y = seq(0, 10, by = 0.5)
 z <- outer(x, y)
 d3 <- expand.grid(x=x,y=y); d3$z <- as.vector(z)
 contourplot(z~x+y, data=d3)
 # labeled '5'-'90'
 contourplot(z~x+y, data=d3, 
    at=seq(5,90, by=5),
    labels=c(seq(5,25, by=5),rep("", 16) ),
    main="Labels only at the first 5 contour lines")
 # contourplot seems to ignore 'extra' labels
 # c() will coerce the 'numeric' elements to 'character' if any others are 'character'
 ?contourplot   # and follow the link in the info about labels to ?panel.levelplot

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