ggplot2折线图给出了“geom_path：每个组只包含一个观察值。你需要调整团体审美吗？“ [英] ggplot2 line chart gives "geom_path: Each group consist of only one observation. Do you need to adjust the group aesthetic?"

问题描述

有了这个数据框（df）：

 年份污染
 1 1999 346.82000 
 2 2002 134.30882 
 3 2005 130.43038 
 4 2008 88.27546 
  

我尝试创建这样的折线图：

  plot5 < -  ggplot（df，aes（year，pollution））+ 
 geom_point（）+ 
 geom_line（）+ 
实验室（x =Year，y =颗粒物排放量（吨），title =巴尔的摩的汽车排放量）
  

我得到的错误是：

geom_path：每个组只包含一个观察值。您是否需要
调整团体美学？

即使我想要一个折线图。我尝试用 geom_line（aes（group = year））替换 geom_line（），但那不起作用。

在一个答案中，我被告知将年份换算成一个因子变量。我做了，问题依然存在。这是 str（df）和 dput（df）的输出：

 'data.frame'：4 obs。 2个变量：
 $ year：num 1 2 3 4 
 $污染：num [1：4（1d）] 346.8 134.3 130.4 88.3 
 ..- attr（*，dimnames ）= 1 
 .. .. $：$ chr1999200220052008
 
结构（列表（年份= c（1，2，3， 4），污染=结构（c（346.82，
 134.308821199349,130​​.430379885892,88.275457392443），.Dim = 4L，.Dimnames = list（
c（1999，2002，2005， ）），.Names = c（year，
pollution），row.names = c（NA，-4L），class =data.frame）
  

解决方案

您只需添加 group = 1 放入ggplot或geom_line aes（）。

lockquote


对于折线图，必须对数据点进行分组，以便它知道指向连接。在这种情况下，它很简单 - 所有点都应该连接，所以group = 1。当使用更多变量并绘制多行时，行的分组通常由变量完成。

参考： Cookbook for R，Chapter：Graphs Bar_and_line_graphs_（ggplot2），Line graphs。

试试这个：

  plot5 < -  ggplot（df，aes（year ，污染，组= 1））+ 
 geom_point（）+ 
 geom_line（）+ 
实验室（x =Year，y =颗粒物排放量（吨），
 title =在巴尔的摩的汽车排放量）
  

With this data frame ("df"):

year pollution
1 1999 346.82000
2 2002 134.30882
3 2005 130.43038
4 2008  88.27546

I try to create a line chart like this:

  plot5 <- ggplot(df, aes(year, pollution)) +
           geom_point() +
           geom_line() +
           labs(x = "Year", y = "Particulate matter emissions (tons)", title = "Motor vehicle emissions in Baltimore")

The error I get is:

geom_path: Each group consist of only one observation. Do you need to adjust the group aesthetic?

The chart appears as a scatter plot even though I want a line chart. I tried to replace geom_line() with geom_line(aes(group = year)) but that didn't work.

In an answer I was told to convert year to a factor variable. I did and the problem persists. This is the output of str(df) and dput(df):

'data.frame':   4 obs. of  2 variables:
 $ year     : num  1 2 3 4
 $ pollution: num [1:4(1d)] 346.8 134.3 130.4 88.3
  ..- attr(*, "dimnames")=List of 1
  .. ..$ : chr  "1999" "2002" "2005" "2008"

structure(list(year = c(1, 2, 3, 4), pollution = structure(c(346.82, 
134.308821199349, 130.430379885892, 88.275457392443), .Dim = 4L, .Dimnames = list(
    c("1999", "2002", "2005", "2008")))), .Names = c("year", 
"pollution"), row.names = c(NA, -4L), class = "data.frame")

解决方案

You only have to add group = 1 into the ggplot or geom_line aes().

For line graphs, the data points must be grouped so that it knows which points to connect. In this case, it is simple -- all points should be connected, so group=1. When more variables are used and multiple lines are drawn, the grouping for lines is usually done by variable.

Reference: Cookbook for R, Chapter: Graphs Bar_and_line_graphs_(ggplot2), Line graphs.

Try this:

plot5 <- ggplot(df, aes(year, pollution, group = 1)) +
         geom_point() +
         geom_line() +
         labs(x = "Year", y = "Particulate matter emissions (tons)", 
              title = "Motor vehicle emissions in Baltimore")

这篇关于ggplot2折线图给出了“geom_path：每个组只包含一个观察值。你需要调整团体审美吗？“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！