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如何在ggplot2的右侧放置转换后的比例？

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18

我在下面附上了一个简单的例子 . 我想在图的右侧添加一个刻度（刻度线和注释），以英尺为单位显示高程 . 我知道ggplot2不会允许两个不同的比例（见Plot with 2 y axes, one y axis on the left, and another y axis on the right），但因为这是相同比例的转换，有没有办法做到这一点？我更喜欢继续使用ggplot2而不必恢复到plot（）函数 .

library(ggplot2)
LakeLevels<-data.frame(Day=c(1:365),Elevation=sin(seq(0,2*pi,2*pi/364))*10+100)
p <- ggplot(data=LakeLevels) + geom_line(aes(x=Day,y=Elevation)) + 
  scale_y_continuous(name="Elevation (m)",limits=c(75,125)) 
p
r ggplot2

4 回答

  • 5

    你应该看一下这个链接http://rpubs.com/kohske/dual_axis_in_ggplot2 .

    我已经根据你的例子调整了那里提供的代码 . 这个修复看起来非常“hacky”，但它会让你成为那里的一部分 . 剩下的唯一部分是弄清楚如何将文本添加到图表的右轴 .

    library(ggplot2)
    library(gtable)
    library(grid)
    LakeLevels<-data.frame(Day=c(1:365),Elevation=sin(seq(0,2*pi,2*pi/364))*10+100)
    p1 <- ggplot(data=LakeLevels) + geom_line(aes(x=Day,y=Elevation)) + 
          scale_y_continuous(name="Elevation (m)",limits=c(75,125))

    p2<-ggplot(data=LakeLevels)+geom_line(aes(x=Day, y=Elevation))+
        scale_y_continuous(name="Elevation (ft)", limits=c(75,125),           
        breaks=c(80,90,100,110,120),
                 labels=c("262", "295", "328", "361", "394"))

    #extract gtable
    g1<-ggplot_gtable(ggplot_build(p1))
    g2<-ggplot_gtable(ggplot_build(p2))

    #overlap the panel of the 2nd plot on that of the 1st plot

    pp<-c(subset(g1$layout, name=="panel", se=t:r))
    g<-gtable_add_grob(g1, g2$grobs[[which(g2$layout$name=="panel")]], pp$t, pp$l, pp$b, 
                       pp$l)

   ia <- which(g2$layout$name == "axis-l")
   ga <- g2$grobs[[ia]]
   ax <- ga$children[[2]]
   ax$widths <- rev(ax$widths)
   ax$grobs <- rev(ax$grobs)
   ax$grobs[[1]]$x <- ax$grobs[[1]]$x - unit(1, "npc") + unit(0.15, "cm")
   g <- gtable_add_cols(g, g2$widths[g2$layout[ia, ]$l], length(g$widths) - 1)
   g <- gtable_add_grob(g, ax, pp$t, length(g$widths) - 1, pp$b)

   # draw it
   grid.draw(g)

    enter image description here

    回复于
  • 4

    我可能已经找到了一个放置轴 Headers 的解决方案，其中一些来自Nate Pope答案的想法可以在这里找到：
    ggplot2: Adding secondary transformed x-axis on top of plot
    关于在gtable中访问grobs的讨论：https://groups.google.com/forum/m/#!topic/ggplot2-dev/AVHHcYqc5uU

    最后，我刚刚添加了该行

    g <- gtable_add_grob(g, g2$grob[[7]], pp$t, length(g$widths), pp$b)

    在致电 grid.draw(g) 之前，这似乎可以解决问题 .
    据我了解，它采用y轴 Headers g2$grob[[7]] 并将其置于最右侧 . 它可能不是美妙的解决方案，但它对我有用 .

    最后一件事 . 找到一种旋转轴 Headers 的方法会很不错 .

    问候，

    蒂姆

    回复于
  • 2

    这个问题已得到解答，但是在ggplot对象的右侧添加辅助轴和辅助比例的一般问题是一直出现的问题 . 我想在下面报告我对问题的调整，基于此线程中的各种答案给出的几个元素以及其他几个线程（参见下面的部分参考列表） .

    我需要批量 生产环境 双y轴图，所以我构建了一个函数 ggplot_dual_axis() . 以下是潜在兴趣的特征：

    • The code displays gridlines for both the y-left and y-right axes （这是我的主要贡献，虽然它是微不足道的）

    • The code prints a euro symbol and embeds it into the pdf （我在那里看到的东西：Plotting Euro Symbol € in ggplot2?）

    • 代码试图避免两次打印某些元素（'尝试'表明我怀疑它是否完全成功）

    未答复的问题：

    • 有没有办法修改 ggplot_dual_axis() 函数以删除其中一个 geom_line() 或 geom_point() 或其他任何可能没有抛出错误，如果没有这样的geom元素 . 在伪代码中像 if has(geom_line) ...

    • 如何通过关键字而不是索引来调用 g2$grobs[[7]] ？这就是它返回的内容： text[axis.title.y.text.232] 我对这个问题的兴趣源于我通过应用类似的技巧尝试 grab 网格线的失败 . 我认为网格线隐藏在 g2$grobs[[4]] 内的某个地方，但我不知道如何访问它们 .

    Edit . 问题我能够自己回答：如何增加右侧的绘图边距，'Euro'标签在哪里？答：例如， theme(plot.margin = unit(c(1,3,0.5,0.8), "lines")) 会做的伎俩 .

    请指出任何明显的问题或建议改进 .

    现在代码：希望它对某人有用 . 正如我所说，我并不要求原创性，这是其他人已经展示的事物的组合 .

    ##' function named ggplot_dual_axis()
##' Takes 2 ggplot plots and makes a dual y-axis plot
##' function takes 2 compulsory arguments and 1 optional argument
##' arg lhs is the ggplot whose y-axis is to be displayed on the left
##' arg rhs is the ggplot whose y-axis is to be displayed on the right
##' arg 'axis.title.y.rhs' takes value "rotate" to rotate right y-axis label
##' The function does as little as possible, namely:
##'  # display the lhs plot without minor grid lines and with a
##'  transparent background to allow grid lines to show
##'  # display the rhs plot without minor grid lines and with a
##'  secondary y axis, a rotated axis label, without minor grid lines
##'  # justify the y-axis label by setting 'hjust = 0' in 'axis.text.y'
##'  # rotate the right plot 'axis.title.y' by 270 degrees, for symmetry
##'  # rotation can be turned off with 'axis.title.y.rhs' option
##'  

ggplot_dual_axis <- function(lhs, rhs, axis.title.y.rhs = "rotate") {
  # 1. Fix the right y-axis label justification
    rhs <- rhs + theme(axis.text.y = element_text(hjust = 0))
  # 2. Rotate the right y-axis label by 270 degrees by default
    if (missing(axis.title.y.rhs) | 
        axis.title.y.rhs %in% c("rotate", "rotated")) {
        rhs <- rhs + theme(axis.title.y = element_text(angle = 270)) 
    }
  # 3a. Use only major grid lines for the left axis
    lhs <- lhs + theme(panel.grid.minor = element_blank())
  # 3b. Use only major grid lines for the right axis
  #     force transparency of the backgrounds to allow grid lines to show
    rhs <- rhs + theme(panel.grid.minor = element_blank(), 
        panel.background = element_rect(fill = "transparent", colour = NA), 
        plot.background = element_rect(fill = "transparent", colour = NA))
# Process gtable objects
  # 4. Extract gtable
    library("gtable") # loads the grid package
    g1 <- ggplot_gtable(ggplot_build(lhs))
    g2 <- ggplot_gtable(ggplot_build(rhs))
  # 5. Overlap the panel of the rhs plot on that of the lhs plot
    pp <- c(subset(g1$layout, name == "panel", se = t:r))
    g <- gtable_add_grob(g1, 
        g2$grobs[[which(g2$layout$name == "panel")]], pp$t, pp$l, pp$b, pp$l)
  # Tweak axis position and labels
    ia <- which(g2$layout$name == "axis-l")
    ga <- g2$grobs[[ia]]
    ax <- ga$children[["axis"]]  # ga$children[[2]]
    ax$widths <- rev(ax$widths)
    ax$grobs <- rev(ax$grobs)
    ax$grobs[[1]]$x <- ax$grobs[[1]]$x - unit(1, "npc") + unit(0.15, "cm")
    g <- gtable_add_cols(g, g2$widths[g2$layout[ia, ]$l], length(g$widths) - 1)
    g <- gtable_add_grob(g, ax, pp$t, length(g$widths) - 1, pp$b)
    g <- gtable_add_grob(g, g2$grobs[[7]], pp$t, length(g$widths), pp$b)
  # Display plot with arrangeGrob wrapper arrangeGrob(g)
    library("gridExtra")
    grid.newpage()
    return(arrangeGrob(g))
}

    还有一些虚假数据和两个以美元和欧元为单位的情节 . 拥有一个可以让你制作一个情节的包裹并且用它来包围调用双y轴情节并不是很酷，它会自动获取你的汇率！ :-)

    # Set directory:
if(.Platform$OS.type == "windows"){
  setwd("c:/R/plots")
} else { 
  setwd("~/R/plots")
}

# Load libraries
library("ggplot2")
library("scales")

# Create euro currency symbol in plot labels, simple version
# avoids loading multiple libraries
# avoids problems with rounding of small numbers, e.g. .0001
labels_euro <- function(x) {# no rounding
paste0("€", format(x, big.mark = ",", decimal.mark = ".", trim = TRUE,
    scientific = FALSE))
} 

labels_dollar <- function(x) {# no rounding: overwrites dollar() of library scales
paste0("$", format(x, big.mark = ",", decimal.mark = ".", trim = TRUE,
    scientific = FALSE))
} 

# Create data
df <- data.frame(
  Year = as.Date(c("2001", "2002", "2003", "2004", "2005", "2006", "2007", "2008", "2009", "2010", "2011", "2012", "2013", "2014", "2015", "2016", "2017", "2018"),
    "%Y"), 
  Dollar = c(0, 9000000, 1000000, 8000000, 2000000, 7000000, 3000000, 6000000, 4000000, 5000000, 5000000, 6000000, 4000000, 7000000, 300000, 8000000, 2000000, 9000000))
# set Euro/Dollar exchange rate at 0.8 euros = 1 dollar
df <- cbind(df, Euro = 0.8 * df$Dollar)
# Left y-axis
p1 <- ggplot(data = df, aes(x = Year, y = Dollar)) + 
    geom_line(linestyle = "blank") + # manually remove the line
    theme_bw(20) +                   # make sure font sizes match in both plots
    scale_x_date(labels = date_format("%Y"), breaks = date_breaks("2 years")) + 
    scale_y_continuous(labels = labels_dollar, 
        breaks = seq(from = 0, to = 8000000, by = 2000000))
# Right y-axis
p2 <- ggplot(data = df, aes(x = Year, y = Euro)) + 
    geom_line(color = "blue", linestyle = "dotted", size = 1) + 
    xlab(NULL) +                     # manually remove the label
    theme_bw(20) +                   # make sure font sizes match in both plots
    scale_x_date(labels = date_format("%Y"), breaks = date_breaks("2 years")) +
    scale_y_continuous(labels = labels_euro, 
        breaks = seq(from = 0, to = 7000000, by = 2000000))

# Combine left y-axis with right y-axis
p <- ggplot_dual_axis(lhs = p1, rhs = p2)
p

# Save to PDF
pdf("ggplot-dual-axis-function-test.pdf", 
  encoding = "ISOLatin9.enc", width = 12, height = 8)
p
dev.off()

embedFonts(file = "ggplot-dual-axis-function-test.pdf", 
           outfile = "ggplot-dual-axis-function-test-embedded.pdf")

    enter image description here

    部分参考清单：

    回复于
  • 15

    要旋转轴 Headers ，请将以下内容添加到p2图表中：

    p2 <- p2 + theme(axis.title.y=element_text(angle=270))
    回复于

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