如何使用 ggplot2 在 r 中轻松创建浮雕图

凹凸图是一种图表，它显示不同组随时间的排名而不是绝对值，以强调组的顺序而不是变化量。

本教程介绍如何使用 ggplot2 在 R 中轻松创建凹凸图。

示例：创建浮雕图形

要在 R 中创建凹凸图，我们首先需要加载两个包： dplyr和ggplot2 ：

 library(ggplot2) #for creating bump chart
library(dplyr) #for manipulating data

接下来，我们将创建一些要使用的数据：

 #set the seed to make this example reproducible
set.seed(10)

data <- data.frame(team = rep(LETTERS[1:5], each = 10),
                   random_num = runif(50),
                   day = rep(1:10, 5))

data <- data %>%
  group_by(day) %>%
  arrange(day, desc(random_num), team) %>% 
  mutate(rank = row_number()) %>%
  A group()

head(data)

# team random_num day rank          
#1 C 0.865 1 1
#2 B 0.652 1 2
#3 D 0.536 1 3
#4 A 0.507 1 4
#5 E 0.275 1 5
#6 C 0.615 2 1

该数据库仅显示五支不同球队在 10 天内的“排名”。

我们可以使用 ggplot2 创建进度图来可视化每个团队在此期间每天的排名：

 ggplot(data, aes(x = day, y = rank, group = team)) +
  geom_line(aes(color = team, alpha = 1), size = 2) +
  geom_point(aes(color = team, alpha = 1), size = 4) +
  scale_y_reverse(breaks = 1:nrow(data))

这个凹凸图以您想要的格式显示数据，但它非常丑陋。通过一些美学上的改变，我们可以使这幅画变得更好。

风格化凹凸图形

为了改善图表的外观，我们可以使用Dominik Koch创建的以下主题：

 my_theme <- function() {

  # Colors
  color.background = "white"
  color.text = "#22211d"

  # Begin construction of chart
  theme_bw(base_size=15) +

    # Format background colors
    theme(panel.background = element_rect(fill=color.background,
                                          color=color.background)) +
    theme(plot.background = element_rect(fill=color.background,
                                          color=color.background)) +
    theme(panel.border = element_rect(color=color.background)) +
    theme(strip.background = element_rect(fill=color.background,
                                          color=color.background)) +

    # Format the grid
    theme(panel.grid.major.y = element_blank()) +
    theme(panel.grid.minor.y = element_blank()) +
    theme(axis.ticks = element_blank()) +

    # Format the legend
    theme(legend.position = "none") +

    # Format title and axis labels
    theme(plot.title = element_text(color=color.text, size=20, face = "bold")) +
    theme(axis.title.x = element_text(size=14, color="black", face = "bold")) +
    theme(axis.title.y = element_text(size=14, color="black", face = "bold",
                                          vjust=1.25)) +
    theme(axis.text.x = element_text(size=10, vjust=0.5, hjust=0.5,
                                          color = color.text)) +
    theme(axis.text.y = element_text(size=10, color = color.text)) +
    theme(strip.text = element_text(face = "bold")) +

    # Plot margins
    theme(plot.margin = unit(c(0.35, 0.2, 0.3, 0.35), "cm"))
}

我们将再次创建凹凸图，但这次我们将删除图例，添加一些图表标签，并使用上面代码中定义的主题：

 ggplot(data, aes(x = as.factor(day), y = rank, group = team)) +
  geom_line(aes(color = team, alpha = 1), size = 2) +
  geom_point(aes(color = team, alpha = 1), size = 4) +
  geom_point(color = "#FFFFFF", size = 1) +
  scale_y_reverse(breaks = 1:nrow(data)) + 
  scale_x_discrete(breaks = 1:10) +
  theme(legend.position = 'none') +
  geom_text(data = data %>% filter(day == "1"),
            aes(label = team, x = 0.5), hjust = .5,
            fontface = "bold", color = "#888888", size = 4) +
  geom_text(data = data %>% filter(day == "10"),
            aes(label = team, x = 10.5), hjust = 0.5,
            fontface = "bold", color = "#888888", size = 4) +
  labs(x = 'Day', y = 'Rank', title = 'Team Ranking by Day') +
  my_theme()

我们还可以通过添加scale_color_manual()参数轻松突出显示其中一行。例如，在下面的代码中，我们将 A 队的线设为紫色，将所有其他线设为灰色：

 ggplot(data, aes(x = as.factor(day), y = rank, group = team)) +
  geom_line(aes(color = team, alpha = 1), size = 2) +
  geom_point(aes(color = team, alpha = 1), size = 4) +
  geom_point(color = "#FFFFFF", size = 1) +
  scale_y_reverse(breaks = 1:nrow(data)) + 
  scale_x_discrete(breaks = 1:10) +
  theme(legend.position = 'none') +
  geom_text(data = data %>% filter(day == "1"),
            aes(label = team, x = 0.5), hjust = .5,
            fontface = "bold", color = "#888888", size = 4) +
  geom_text(data = data %>% filter(day == "10"),
            aes(label = team, x = 10.5), hjust = 0.5,
            fontface = "bold", color = "#888888", size = 4) +
  labs(x = 'Day', y = 'Rank', title = 'Team Ranking by Day') +
  my_theme() +
  scale_color_manual(values = c('purple', 'grey', 'grey', 'grey', 'grey'))

如果需要，我们还可以突出显示多行：

 ggplot(data, aes(x = as.factor(day), y = rank, group = team)) +
  geom_line(aes(color = team, alpha = 1), size = 2) +
  geom_point(aes(color = team, alpha = 1), size = 4) +
  geom_point(color = "#FFFFFF", size = 1) +
  scale_y_reverse(breaks = 1:nrow(data)) + 
  scale_x_discrete(breaks = 1:10) +
  theme(legend.position = 'none') +
  geom_text(data = data %>% filter(day == "1"),
            aes(label = team, x = 0.5), hjust = .5,
            fontface = "bold", color = "#888888", size = 4) +
  geom_text(data = data %>% filter(day == "10"),
            aes(label = team, x = 10.5), hjust = 0.5,
            fontface = "bold", color = "#888888", size = 4) +
  labs(x = 'Day', y = 'Rank', title = 'Team Ranking by Day') +
  my_theme() +
  scale_color_manual(values = c('purple', 'steelblue', 'grey', 'grey', 'grey'))