r - 用ggplot中的一个x轴绘制两个图（3个变量） [英] r - Ploting two plots (3 variables) with one x-axes in ggplot

问题描述

我试图在一张图中绘制两个流量和一个降雨量数据。我已经把它分解成顶部和底部，如下图所示。在这里，我有两个问题与这个情节，花了几年，但无法解决它。

1. 为什么观察到的流程总是黑色的，即使我已经设置它变成蓝色？我不小心使用了其他一些参数来覆盖它吗？
   

2. 最重要的是，我如何能够为底部图表添加图例？我尝试了许多不同的代码，但他们似乎并不适合我。

     x = data.frame（date = Date，雨= Obs_rain，obsflow = Obs_flow，simflow = Sim_flow）
    
    g.top < -  ggplot（x，aes（x = date，y = rain，ymin = 0，ymax = rain））+ 
    geom_linerange（）+ 
    scale_y_continuous（trans =reverse）+ 
    theme_bw（）+ 
    theme（plot.margin = unit（c（1,5，-30， 6），units =points），
    axis.title.y = element_text（vjust = 0.3））+ 
    labs（x =Date，y =Rain（mm））
    
    g.bottom < -  ggplot（x，aes（x = date，y = obsflow，ymin = 0，ymax = obsflow），color =blue，size = 0.5）+ 
    geom_linerange（）+ #plot flow 
    geom_linerange（aes（y = simflow，ymin = 0，ymax = simflow），color =red，size = 0.5）+ 
    labs（x =Date ，y =River flow（ML / day））+ 
    theme_classic（）+ 
    theme（plot.background = element_rect（fill =transparent），
    plot.margin =单元（c（2 ，0,1,1），units =lines））
    
    grid.arrange（g.top，g.bottom，heights = c（1/5，4/5））
     

更新：

我用蓝线的颜色解决了这个问题。我无意中将论点置于错误的地方。但我仍然在为这个传奇而努力。

  g.bottom <-ggplot（x，aes（x = date，y = obsflow，ymin = 0，ymax = obsflow））+ 
 geom_linerange（color =blue，size = 0.5）+ #plot flow 
  

解决方案

解释@pierre意味着什么......使用 reshape2 :: melt 将数据从宽格式转换为长格式 c $ c>，因此每个日期的流类型都在一列 flow_type 中，并且该值是另一个（ flow_val ）。然后指定 flow_type 作为分配变量的颜色：



  require（reshape2）
 
 x.melted<  -  melt（x，id.vars = c（date，rain），variable.name =flow_type，
 （x =熔点，aes（x =日期），大小= 0.5）+ 
 geom_linerange（aes（ymin = value.name =flow_val）
 
 g.bottom<  -  ggplot 0，ymax = flow_val，color = flow_type））+ #plot flow 
 labs（x =Date，y =River flow（ML / day））+ 
 theme_classic（）+ 
主题（plot.background = element_rect（fill =transparent），
 plot.margin =单位（c（2,0,1,1），units =lines），
 legend .position =bottom）+ 
 scale_colour_manual（guide = guide_legend（title =Flow Type），
 values = c（obsflow=blue，simflow=red） ）
  




I am trying to plot two flows and one rainfall data in one graph. I have broke it up into top and bottom parts as shown in the following pic. Here I have two issues with this plots and spent ages but cannot solve it.

1. Why the observed flow always in black, even I have set it up as blue? Did I accidentally used some other arguments to overwrite it?

2. The most importantly is, how do I able to add a legend for the bottom plot? I tried many different codes but they don't seem to work for me.

   x = data.frame(date = Date, rain = Obs_rain, obsflow = Obs_flow,simflow=Sim_flow)
   
   g.top <- ggplot(x, aes(x = date, y = rain, ymin=0, ymax=rain)) +
            geom_linerange() +
            scale_y_continuous(trans = "reverse") +
            theme_bw() +
            theme(plot.margin = unit(c(1,5,-30,6),units="points"),
            axis.title.y = element_text(vjust =0.3)) +
            labs(x = "Date",y = "Rain(mm)")
   
   g.bottom <- ggplot(x, aes(x = date, y = obsflow, ymin=0, ymax=obsflow), colour = "blue",size=0.5) +
            geom_linerange() +  #plot flow
            geom_linerange(aes(y = simflow, ymin=0, ymax=simflow), colour = "red", size =0.5)+ 
            labs(x = "Date", y = "River flow (ML/day)") +
            theme_classic() +
            theme(plot.background = element_rect(fill = "transparent"),
            plot.margin = unit(c(2,0,1,1),units="lines"))
   
   grid.arrange(g.top,g.bottom, heights = c(1/5, 4/5)) 
   

Update:

I have resolved the issue with blue line colour. I accidently put arguments in the wrong place. But I'm still struggling with the legend.

    g.bottom <- ggplot(x, aes(x = date, y = obsflow, ymin=0, ymax=obsflow)) +
                geom_linerange(colour = "blue",size=0.5) +  #plot flow

解决方案

As an explanation of what @pierre means... turn your data from "wide" to "long" format using reshape2::melt, so that the flow type for each date is in one column flow_type, and the value is another (flow_val). Then you specify flow_type as the grouping variable with which to assign colour:

require(reshape2)

x.melted <- melt(x, id.vars = c("date", "rain"), variable.name="flow_type",
                 value.name="flow_val")

g.bottom <- ggplot(x.melted, aes(x = date),size=0.5) +
  geom_linerange(aes(ymin=0, ymax=flow_val, colour=flow_type)) +  #plot flow
  labs(x = "Date", y = "River flow (ML/day)") +
  theme_classic() +
  theme(plot.background = element_rect(fill = "transparent"),
        plot.margin = unit(c(2,0,1,1),units="lines"), 
        legend.position="bottom") + 
  scale_colour_manual(guide = guide_legend(title = "Flow Type"), 
                      values = c("obsflow"="blue", "simflow"="red"))

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