ggplot2：翻转轴并保持数据的高宽比 [英] ggplot2: Flip axes and maintain aspect ratio of data

问题描述

在ggplot2中， coord_fixed（）坐标系确保数据的宽高比保持在给定值。所以，面板的形状会发生变化以保持数据的形状。同时 coord_flip（）交换图的坐标轴。但是，ggplot2中的图必须只有一个坐标系，所以这些函数不能组合。

我的问题是：

是否存在一种将行为的 coord_fixed（）和 coord_flip（），产生一个x轴和y轴交换的坐标系，数据的纵横比？

这是一个受欢迎的问题，但常见的答案是不正确的：

• 
  
  

  解决方案I在实践中可能会使用的是在 ggstance 包中使用水平几何（尽管这可能并不总是可行）。

  
  
  

  注意：这将只给出两个连续比例的精确正确答案，其中等于乘法扩展参数（即默认值）。
  

  In ggplot2, the coord_fixed() coordinate system ensures that the aspect ratio of the data is maintained at a given value. So, the shape of the panel changes to maintain the shape of the data. Meanwhile coord_flip() swaps the axes of the plot. However, a plot in ggplot2 must have exactly one coordinate system, so these functions cannot be combined.

  My question is:

  Does there exist a way to combine the behaviours of coord_fixed() and coord_flip(), resulting in a coordinate system with the x and y axes exchanged and a fixed aspect ratio of the data?

  This is a popular question, however the common answer is incorrect:

  • How do I to fix aspect ratio and apply coord_flip in ggplot2?
  • Flipping and maintaining aspect ratio of a chart in ggplot2

  The commonly suggested answer is to use coord_flip() together with theme(aspect.ratio = 1) instead of coord_fixed(). However, as per the ggplot2 documentation, this setting refers to the "aspect ratio of the panel." Thus, the data will change shape to maintain the shape of the panel.

  I suspect that this is a feature that does not currently exist in ggplot2. But more importantly I think that a correct solution or at least response to this question should be documented.

  Quick minimal example of the issue:

  library(ggplot2)
  x <- 1:100; data <- data.frame(x = x, y = x * 2)
  p <- ggplot(data, aes(x, y)) + geom_point()
  
  p # by default panel and data both fit to device window
  p + coord_fixed() # panel changes shape to maintain shape of data
  p + theme(aspect.ratio = 1) # data changes shape to maintain shape of panel
  p + coord_fixed() + coord_flip() # coord_flip() overwrites coord_fixed()
  
  # popular suggested answer does not maintain aspect ratio of data:
  p + coord_flip() + theme(aspect.ratio = 1)
  

  解决方案

  I agree that the theme solution isn't really a proper one. Here is a solution that does work programatically by calculating the aspect from the actual axes ranges stored in the plot object, but it takes a few lines of code:

  ranges <- ggplot_build(p)$layout$panel_ranges[[1]][c('x.range', 'y.range')]
  sizes <- sapply(ranges, diff)
  aspect <- sizes[1] / sizes[2]
  
  p + coord_flip() + theme(aspect.ratio = aspect)
  

  The solution I would probably use in practice, is to use the horizontal geoms in the ggstance package (although this may not always be feasible).

  Note: This will only give the exact correct answer for two continuous scales with an equal multiplicative extend argument (i.e. the default).

  这篇关于ggplot2：翻转轴并保持数据的高宽比的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！