如何在ggplot geom_tile中正确使用构面，同时保持长宽比不变？

Question

我正在尝试创建一个“相似度图”，以快速显示表格中的项目相似度与其他项目。

一个简单的例子：

要使用的“ property_data.csv”文件：

"","Country","Town","Property","Property_value"
"1","UK","London","Road_quality","Bad"
"2","UK","London","Air_quality","Very bad"
"3","UK","London","House_quality","Average"
"4","UK","London","Library_quality","Good"
"5","UK","London","Pool_quality","Average"
"6","UK","London","Park_quality","Bad"
"7","UK","London","River_quality","Very good"
"8","UK","London","Water_quality","Decent"
"9","UK","London","School_quality","Bad"
"10","UK","Liverpool","Road_quality","Bad"
"11","UK","Liverpool","Air_quality","Very bad"
"12","UK","Liverpool","House_quality","Average"
"13","UK","Liverpool","Library_quality","Good"
"14","UK","Liverpool","Pool_quality","Average"
"15","UK","Liverpool","Park_quality","Bad"
"16","UK","Liverpool","River_quality","Very good"
"17","UK","Liverpool","Water_quality","Decent"
"18","UK","Liverpool","School_quality","Bad"
"19","USA","New York","Road_quality","Bad"
"20","USA","New York","Air_quality","Very bad"
"21","USA","New York","House_quality","Average"
"22","USA","New York","Library_quality","Good"
"23","USA","New York","Pool_quality","Average"
"24","USA","New York","Park_quality","Bad"
"25","USA","New York","River_quality","Very good"
"26","USA","New York","Water_quality","Decent"
"27","USA","New York","School_quality","Bad"

码：

prop <- read.csv('property_data.csv')

Property_col_vector <- c("NA" = "#e6194b",
                "Very bad" = "#e6194B",
                "Bad" = "#ffe119",
                "Average" = "#bfef45",
                "Decent" = "#3cb44b",
                "Good" = "#42d4f4",
                "Very good" = "#4363d8")

plot_likeliness <- function(town_property_table){
    g <- ggplot(town_property_table, aes(Property, Town)) +
      geom_tile(aes(fill = Property_value, width=.9, height=.9)) +
      theme_classic() +
      theme(axis.text.x = element_text(angle = 90, hjust = 1, vjust=0.5),
            strip.text.y = element_text(angle = 0)) +
      scale_fill_manual(values = Property_col_vector) +
      coord_fixed()
    return(g)
}

summary_town_plot <- plot_likeliness(prop)

输出：

这看起来很棒！现在，由于使用了coord_fixed（）函数，因此创建了一个看起来不错的图，但现在我想创建一个由Country组成的图。

为此，我创建了以下函数：

plot_likeliness_facetted <- function(town_property_table){
  g <- ggplot(town_property_table, aes(Property, Town)) +
    geom_tile(aes(fill = Property_value, width=.9, height=.9)) +
    theme_classic() +
    theme(axis.text.x = element_text(angle = 90, hjust = 1, vjust=0.5),
          strip.text.y = element_text(angle = 0)) +
    scale_fill_manual(values = Property_col_vector) +
    facet_grid(Country ~ .,
               scale = 'free_y')
  return(g)
}

facetted_town_plot <- plot_likeliness_facetted(prop)
facetted_town_plot

结果：

但是，现在我的图块已拉伸，如果我尝试使用'+ coords_fixed（）'，则会收到错误消息：

Error: coord_fixed doesn't support free scales

我如何才能使图面化，但要保持长宽比？请注意，我正在按顺序绘制这些图形，因此我不希望用手动值对图形的高度进行硬编码，这是我需要的解决方案，我需要一些可以随表中值的数量动态缩放的东西。

非常感谢您的帮助！

编辑：虽然在其他地方稍有不同的情况下询问了同一问题，但它有多个答案，没有一个被标记为解决该问题。

Answer 1

theme(aspect.ratio = 1)并且space = 'free'似乎工作。

plot_likeliness_facetted <- function(town_property_table){
  g <- ggplot(town_property_table, aes(Property, Town)) +
    geom_tile(aes(fill = Property_value, width=.9, height=.9)) +
    theme_classic() +
    theme(axis.text.x = element_text(angle = 90, hjust = 1, vjust=0.5),
          strip.text.y = element_text(angle = 0), aspect.ratio = 1) +
    scale_fill_manual(values = Property_col_vector) +
    facet_grid(Country ~ .,
               scale = 'free_y', space = 'free')
  return(g)
}