在ggplot中如何确定纵横比?

I'm trying to resize a plot to fit into my document, but I'm having difficulties getting the plotted diagram do be a square.

我试着调整一个图的大小以适应我的文档，但是我很难把这个图画成正方形。

Example:

例子:

pdf(file = "./out.pdf", width = 5, height = 5)
p <- ggplot(mydata, aes(x = col1, y = col2))
print(p)
aux <- dev.off()

Although the limits for x and y are the same, the plot in the result isn't square. I guess that R makes the enclosing panel 5x5" but doesn't care about the actual diagram size.

虽然x和y的极限是相同的，但是结果的图形并不平方。我猜是R制作了封装的面板5x5"但是并不关心实际的图大小。

How can I unsquash my diagrams?

我怎样才能解压缩我的图表?

3 个解决方案

#1

In ggplot the mechanism to preserve the aspect ratio of your plot is to add a coord_fixed() layer to the plot. This will preserve the aspect ratio of the plot itself, regardless of the shape of the actual bounding box.

在ggplot中，保存图的纵横比的机制是向图中添加coord_fixed()层。这将保持图形本身的纵横比，而不考虑实际边框的形状。

(I also suggest you use ggsave to save your resulting plot to pdf/png/etc, rather than the pdf(); print(p); dev.off() sequence.)

(我也建议你使用ggsave将你的结果保存为pdf/png/等格式，而不是pdf();打印(p);dev.off()序列。)

library(ggplot2)
df <- data.frame(
    x = runif(100, 0, 5),
    y = runif(100, 0, 5))

ggplot(df, aes(x=x, y=y)) + geom_point() + coord_fixed()

#2

To ensure a particular aspect ratio, e.g. for square, use theme(aspect.ratio=1).

为了确保一个特定的纵横比，例如正方形，使用主题(aspect.ratio=1)。

Andrie's answer doesn't give the full picture, as the example provides perhaps unnatural data where range of x equals the range of y. If however the data were:

Andrie的回答并没有给出完整的结果，因为这个例子可能提供了不自然的数据，其中x的范围等于y的范围。

df <- data.frame(
  x = runif(100, 0, 50),
  y = runif(100, 0, 5))
ggplot(df, aes(x=x, y=y)) + geom_point() + coord_fixed()

then the plot would look like this:

然后情节是这样的:

The coord_fixed() function also has an argument to adjust the ratio of axes:

coord_fixed()函数还有一个参数来调整坐标轴的比例:

ratio aspect ratio, expressed as y / x

比值纵横比，表示为y / x。

So that the plot could be made square with:

这样，我们就可以把整个情节平面化:

ggplot(df, aes(x=x, y=y)) + geom_point() + coord_fixed(ratio=10)

But you need to adjust this with the limits of the variables or plot area (not all limits are nicely divisible by whole numbers like these examples).

但是您需要使用变量或绘图区域的限制来调整它(并不是所有的限制都可以很好地被像这些例子那样的整数整除)。

#3

For completeness sake: If you want to take very different axis limits into account:

为了完整性起见:如果您想考虑非常不同的轴的限制:

df <- data.frame(
  x = runif(100, 0, 5000),
  y = runif(100, 0, 5))
ratio.display <- 4/3
ratio.values <- (max(df$x)-min(df$x))/(max(df$y)-min(df$y))
plot <- ggplot(df, aes(x=x, y=y)) + geom_point()
plot + coord_fixed(ratio.values / ratio.display)

Resulting in:

导致: