如何用ggplot2将点和线叠加到轮廓图上？ [英] How can I overlay points and lines onto a contour plot with ggplot2?

问题描述

我想用我想突出显示的特定点（这些点存储在不同的数据集中）标注等值线图。当我尝试时，出现错误：
$ b

错误：美学必须是长度为1或与dataProblems的长度相同：z

但是，当我尝试制作一个可重复的示例时，出现了另一个错误：

eval（expr，envir，enclos）中的错误：找不到对象'z'

可重现的例子的代码如下：

  library（mnormt）
 library（dplyr）
库（ggplot2）
 
f<  - 函数（x，y）{
 dmnorm（x = c（x，y），
 mean = c（0,0）， 
 varcov = diag（2））
} 
f < -  Vectorize（f）
 
 
 xmesh < -  seq（from = -3， to = 3，length.out = 100）
 ymesh < -  seq（from = -3，to = 3，length.out = 100）
 dummy<  -  expand.grid（x = xmesh ，y = ymesh）
 dummy $ z <-f（dummy $ x，dummy $ y）
 
 stuff<  -  data_frame（x = c（0,0,1）， 
y = c（0，-1，-1），
 point = c（O，P，Q））
 
 dummy％>％
 ggplot （aes（x = x，y = y，z = z））+ 
 stat_contour（aes（color = ..level ..））+ 
 labs（color =density）+ 
 geom_point（data = stuff，mapping = aes（x = x，y = y，color = point））
  

ggplot 调用传递给geoms的其余部分。所以这个错误告诉你它不能找到z内部的东西，它仍然认为z应该是从最初的调用z.

有很多种方法为了解决这个问题，我认为解决这个问题的最简单方法是分别给每个geom数据：

  ggplot（）+ 
 stat_contour（data = dummy，aes（x = x，y = y，z = z，color = ..level ..））+ 
 labs（color =density）+ 
 geom_point（data = stuff，aes（x = x，y = y，fill = factor（point）），pch = 21）
  

注意。您还有一个问题，即颜色无法映射到两个不同的几何元素，所以我使用pch和fill填充了它。

I want to annotate a contour plot with particular points that I want to highlight (where these points are stored in a different data set). When I try, I get an error:

Error: Aesthetics must either be length one, or the same length as the dataProblems:z

However, when I tried to make a reproducible example, I get a different error:

Error in eval(expr, envir, enclos) : object 'z' not found

The code for the reproducible example is below:

library(mnormt)
library(dplyr)
library(ggplot2)

f <- function(x, y) {
    dmnorm(x = c(x, y),
            mean = c(0, 0),
            varcov = diag(2))
}
f <- Vectorize(f)


xmesh <- seq(from = -3, to = 3, length.out = 100)
ymesh <- seq(from = -3, to = 3, length.out = 100)
dummy <- expand.grid(x = xmesh, y = ymesh)
dummy$z <- f(dummy$x, dummy$y)

stuff <- data_frame(x = c(0, 0, 1),
                    y = c(0, -1, -1),
                    point = c("O", "P", "Q"))

dummy %>%
    ggplot(aes(x = x, y = y, z = z)) +
    stat_contour(aes(color = ..level..)) +
    labs(color = "density") + 
    geom_point(data = stuff, mapping = aes(x = x, y = y, color = point))

解决方案

ggplot passes the aes from the first ggplot call to the rest of the geoms, unless told otherwise. So the error is telling you that it cannot find z inside stuff, and it still thinks that the z should be z from the initial call.

There are a range of ways to fix this, I think the easiest way to fix it is to give each geom its data separately:

ggplot() +
  stat_contour(data = dummy, aes(x = x, y = y, z = z, color = ..level..)) +
  labs(color = "density") + 
  geom_point(data = stuff, aes(x = x, y = y, fill = factor(point)), pch = 21)

NB. you also have a problem where colour cannot be mapped in two different geoms, so I've fixed it using pch and fill.

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