r - 以美国的形状排列 ggplot 刻面

Question

我有一个针对美国每个州的一个方面的 ggplot。我想将这些刻面排列成美国形状，边界参差不齐(ordered like the second map，但没有夏威夷或阿拉斯加)。

为此，我创建了一个按美国州排序的州级因子变量，在 map 上从左到右读取。这个因素还包含我想删除的空白方面的“空间持有者”。我听从了 this post 的建议(请参阅对提供的答案的编辑)但是 names(g$grobs)是NULL，所以我无法实现他们的答案。有什么想法我能做什么？

这是我的代码:

library(ggplot2)
library(fivethirtyeight)
library(dplyr)
library(gridExtra)

data("police_deaths")
police_deaths_count <- police_deaths %>% arrange(state, -year) %>% group_by(state, year) %>% count()
police_deaths_count <- police_deaths_count %>% arrange(state, -year) %>% 
  filter(year %in% c(1970:2015) & !state %in% c("AK", "HI", "US", "GU", "MP", "PR", "RR", "TR", "VI"))

police_deaths_count$state.name <- state.name[match(police_deaths_count$state, state.abb)]
police_deaths_count$state.name[police_deaths_count$state == "DC"] <- "Washington DC"

police_deaths_count$state.reorder <- factor(police_deaths_count$state.name,
                                         levels = c("e1", "e2", "e3", "e4", "e5", "e6", "e7", "e8", "e9", "e10", "Maine",
                                                    "e11", "e12", "e13", "e14", "e15", "e16", "e17", "e18", "e19", "Vermont", "New Hampshire",
                                                    "Washington", "Idaho", "Montana", "North Dakota", "Minnesota", "Illinois", "Wisconsin", "Michigan", "New York", "Massachusetts", "Rhode Island",
                                                    "Oregon", "Nevada", "Wyoming", "South Dakota", "Iowa", "Indiana", "Ohio", "Pennsylvania", "New Jersey", "Connecticut", "e20",
                                                    "California", "Utah", "Colorado", "Nebraska", "Missouri", "Kentucky", "West Virginia", "Virginia", "Maryland", "Washington DC", "e21",
                                                    "e22", "Arizona", "New Mexico", "Kansas", "Arkansas", "Tennessee", "North Carolina", "South Carolina", "Delaware", "e23", "e24",
                                                    "e25", "e26", "e27", "Oklahoma", "Louisiana", "Mississippi", "Alabama", "Georgia", "e28", "e29",
                                                    "e30", "e31", "e32", "e33", "Texas", "e34", "e35", "e36", "e37", "Florida"))

police_deaths_count2 <- police_deaths_count %>% filter(!(state=="NY" & year==2001))

plot1 <- ggplot(subset(police_deaths_count2, is.na(state.name)==F), #take away 9-11 peak to see trends without it
               aes(y = n, x = year)) +
  geom_line() + 
  facet_wrap( ~ state.reorder, ncol = 11, drop = F) +
  theme(axis.text.x = element_text(angle = 45, hjust = 1)) +
  ylab("Count of police deaths") +
  xlab("Year")

#the order of these facets is what I want. From here, I'd like to display the facets e1, e2, ..., e37 as completely blank by removing their facet strips and panels.
plot1

#A SO post (next line) provides a potential solution, but it doesn't work for me
#https://stackoverflow.com/questions/30372368/adding-empty-graphs-to-facet-wrap-in-ggplot2 
g <- ggplotGrob(plot1)
names(g$grobs) #this is NULL so I can't implement the SO answer.
g$layout$name

Answer 1

一个 hack-ish 选项是为空面创建唯一的空白条形标签，以便它们可以用作占位符，但不创建任何可见的条形标签。使用州缩写而不是全名可能会更好，但我在这里没有这样做。这是一个例子:

library(ggplot2)
library(fivethirtyeight)
library(dplyr)
library(gridExtra)

data("police_deaths")
police_deaths_count <- police_deaths %>% arrange(state, -year) %>% group_by(state, year) %>% count()
police_deaths_count <- police_deaths_count %>% arrange(state, -year) %>% 
  filter(year %in% c(1970:2015) & !state %in% c("AK", "HI", "US", "GU", "MP", "PR", "RR", "TR", "VI"))

# Create unique blank strip labels for empty facets
bl = sapply(1:37, function(n) paste(rep(" ",n),collapse=""))

police_deaths_count$state.name <- state.name[match(police_deaths_count$state, state.abb)]
police_deaths_count$state.name[police_deaths_count$state == "DC"] <- "Washington DC"

police_deaths_count$state.reorder <- factor(police_deaths_count$state.name,
                                            levels = c(bl[1:10], "Maine",
                                                       bl[11:19], "Vermont", "New Hampshire",
                                                       "Washington", "Idaho", "Montana", "North Dakota", "Minnesota", "Illinois", "Wisconsin", "Michigan", "New York", "Massachusetts", "Rhode Island",
                                                       "Oregon", "Nevada", "Wyoming", "South Dakota", "Iowa", "Indiana", "Ohio", "Pennsylvania", "New Jersey", "Connecticut", bl[20],
                                                       "California", "Utah", "Colorado", "Nebraska", "Missouri", "Kentucky", "West Virginia", "Virginia", "Maryland", "Washington DC", bl[21],
                                                       bl[22], "Arizona", "New Mexico", "Kansas", "Arkansas", "Tennessee", "North Carolina", "South Carolina", "Delaware", bl[23:24],
                                                       bl[25:27], "Oklahoma", "Louisiana", "Mississippi", "Alabama", "Georgia", bl[28:29],
                                                       bl[30:33], "Texas", bl[34:37], "Florida"))


police_deaths_count2 <- police_deaths_count %>% filter(!(state=="NY" & year==2001))

plot1 <- ggplot(subset(police_deaths_count2, is.na(state.name)==F), #take away 9-11 peak to see trends without it
                aes(y = n, x = year)) +
  geom_line() + 
  facet_wrap( ~ state.reorder, ncol = 11, drop = F, strip.position="bottom") +
  theme_classic() +
  theme(axis.text.x = element_blank(),
        strip.background=element_blank(),
        axis.line=element_blank(),
        axis.ticks=element_blank()) +
  ylab("Count of police deaths") +
  xlab("Year (1970 - 2015)")