在一个窗口中使用 ggplot 绘制多个直方图，其中包含多个变量答案

【问题标题】：Plot several histograms with ggplot in one window with several variables在一个窗口中使用 ggplot 绘制多个直方图，其中包含多个变量
【发布时间】：2014-11-07 13:17:05
【问题描述】：

我想使用 ggplot 绘制 6 个直方图。每个直方图对应一个产品（例如 Modis 2000、Modis 2005 等）。 x 轴是土地利用（农业、建筑等），y 轴是百分比误差，包括佣金误差 (_CE) 和遗漏误差 (_OE)。对于每种土地利用，这两个错误的条应该是相邻的（见附图。

structure(list(X = structure(c(1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 
    1L, 2L, 1L, 2L), .Label = c("Forest_CE", "Forest_OE"), class = "factor"), 
        Product = structure(c(5L, 5L, 6L, 6L, 3L, 3L, 4L, 4L, 1L, 
        1L, 2L, 2L), .Label = c("CCI 2000", "CCI 2005", "GLC-SHARE2000", 
        "GLC-SHARE2005", "Modis 2000", "Modis 2005"), class = "factor"), 
        Agriculture = c(45.42827657, 36.98156682, 48.19181349, 55.41838134, 
        41.6579589, 29.74910394, 42.88911495, 7.112253642, 38.86168911, 
        86.76103247, 44.08410549, 88.54166667), Built.up = c(0.990712074, 
        0.115207373, 0.702079746, 0.137174211, 0.104493208, 0, 0.996948118, 
        0, 1.591187271, 0, 1.069137562, 0), Mining = c(0.557275542, 
        0, 0.132467877, 0, 0.870776733, 0, 0.22380468, 0, 1.407588739, 
        0, 0.249465431, 0), Other = c(52.73477812, 51.38248848, 50.73519671, 
        44.17009602, 56.94879833, 70.25089606, 55.50356053, 77.97772065, 
        57.71113831, 11.07410491, 54.16963649, 7.899305556), Water = c(0.288957688, 
        11.52073733, 0.238442178, 0.274348422, 0.417972832, 0, 0.386571719, 
        14.91002571, 0.428396573, 2.164862614, 0.427655025, 3.559027778
        )), .Names = c("X", "Product", "Agriculture", "Built.up", 
    "Mining", "Other", "Water"), class = "data.frame", row.names = c(NA, 
    -12L))

这是我想要实现的，但此直方图是为一种产品制作的。我想为每种产品创建相同类型的直方图，并且所有直方图都应该在一个窗口中弹出。有人可以帮我这样做吗？感谢您的帮助。

【问题讨论】：

标签： r ggplot2 histogram

【解决方案1】：

您可以使用facet_wrap 来实现您所描述的：

yellowmellow <- structure(list(X = structure(c(1L, 2L, 1L, 2L, 1L, 2L, 1L, 2L, 
                               1L, 2L, 1L, 2L), .Label = c("Forest_CE", "Forest_OE"), class = "factor"), 
               Product = structure(c(5L, 5L, 6L, 6L, 3L, 3L, 4L, 4L, 1L, 
                                     1L, 2L, 2L), .Label = c("CCI 2000", "CCI 2005", "GLC-SHARE2000", 
                                                             "GLC-SHARE2005", "Modis 2000", "Modis 2005"), class = "factor"), 
               Agriculture = c(45.42827657, 36.98156682, 48.19181349, 55.41838134, 
                               41.6579589, 29.74910394, 42.88911495, 7.112253642, 38.86168911, 
                               86.76103247, 44.08410549, 88.54166667), Built.up = c(0.990712074, 
                                                                                    0.115207373, 0.702079746, 0.137174211, 0.104493208, 0, 0.996948118, 
                                                                                    0, 1.591187271, 0, 1.069137562, 0), Mining = c(0.557275542, 
                                                                                                                                   0, 0.132467877, 0, 0.870776733, 0, 0.22380468, 0, 1.407588739, 
                                                                                                                                   0, 0.249465431, 0), Other = c(52.73477812, 51.38248848, 50.73519671, 
                                                                                                                                                                 44.17009602, 56.94879833, 70.25089606, 55.50356053, 77.97772065, 
                                                                                                                                                                 57.71113831, 11.07410491, 54.16963649, 7.899305556), Water = c(0.288957688, 
                                                                                                                                                                                                                                11.52073733, 0.238442178, 0.274348422, 0.417972832, 0, 0.386571719, 
                                                                                                                                                                                                                                14.91002571, 0.428396573, 2.164862614, 0.427655025, 3.559027778
                                                                                                                                                                 )), .Names = c("X", "Product", "Agriculture", "Built.up", 
                                                                                                                                                                                "Mining", "Other", "Water"), class = "data.frame", row.names = c(NA, 
                                                                                                                                                                                                                                                 -12L))

# using reshape 2, we change the data frame to long format
mean.long = melt(yellowmellow, measure.vars = 3:7, variable.name = "Land", value.name = "Percentage")


ggplot(mean.long, aes(x=Land, y=Percentage, fill=factor(X))) + theme_bw() + facet_wrap(~Product)+ 
  geom_bar(position=position_dodge(.9)) + # this line is not needed. Only included as a fix for legend/key random line
  geom_bar(position=position_dodge(.9), stat="identity", colour="black", legend = FALSE)  + 
  scale_fill_grey(start=.4)

我猜这就是你要找的。我基本上将您的数据放入数据框（黄色）并使用melt 将其转换为长格式数据，以便与ggplot 和facet_wrap 一起使用。这是上面代码的输出：

编辑：或者，您可以通过将 nrow=1 添加到 facet_wrap 来获得单行上的所有图表：

ggplot(mean.long, aes(x=Land, y=Percentage, fill=factor(X))) + theme_bw() + facet_wrap(~Product, nrow=1)+
 geom_bar(position=position_dodge(.9)) + # this line is not needed. Only included as a fix for legend/key random line
  geom_bar(position=position_dodge(.9), stat="identity", colour="black", legend = FALSE)  + 
  scale_fill_grey(start=.4)

看起来像这样：

我使用以下尺寸导出此图像以避免重叠 x 轴标签：2000*1500。

您可以使用不同的导出大小和字体大小来找到您想要的。

【讨论】：