ggplot2优雅绘制等高线地图

library(tidyverse)
install.packages("mapdata")
install.packages("stopwords")
library(mapdata)
library(ggtext)
library(stopwords)
library(tidytext)
library(ggrepel)
library(tidyverse)

historical_markers <- read_csv('historical_markers.csv') 
no_markers <- read_csv('no_markers.csv') 

combined <- historical_markers %>%
  filter(!(state_or_prov %in% c("Alaska", "Hawaii", "Puerto Rico"))) %>%  # 筛选出除阿拉斯加、夏威夷和波多黎各外的州或省
  group_by(state_or_prov) %>%
  summarize(text = paste(title, collapse = " "))  # 按州或省分组，并将每组的标题合并成一个字符串
combined$words <- str_replace_all(combined$text, "[[:punct:]]", "")  # 移除所有的标点符号

state_info <- map_data("state")  # 加载美国各州的地图数据

state_labels <- state_info %>%
   group_by(region) %>%
   summarise(min_long = min(long),max_long = max(long),
             min_lat = min(lat),max_lat = max(lat),
             range_long = max_long - min_long,
             range_lat = max_lat - min_lat,
             long = min_long + range_long/2,
             lat = min_lat + range_lat/2) %>%
  mutate(long= case_when(region %in% c("michigan", "florida") ~ long + 2,region == "idaho" ~ long -1,
                         region == "virginia" ~ long + 1,RUE ~ long)) %>%
  mutate(lat = case_when(region == "maryland" ~ lat + 0.5,TRUE ~ lat)) %>%
  select(region, long, lat) %>%
  right_join(word_by_state, by = c("region" = "state_or_prov"))  # 计算每个州的地理中心位置，并将其与词汇数据合并

historical_markers %>%
  filter(!(state_or_prov %in% c("Alaska", "Hawaii", "Puerto Rico"))) %>%
  ggplot()+
  geom_polygon(aes(x=long, y=lat, group = group), data = state_info, fill = NA, color = "black", linewidth = 0.15)+
  coord_fixed(ratio = 1.3) +
  geom_density2d_filled(aes(x=longitude_minus_w, y=latitude_minus_s), show.legend = FALSE, alpha=0.4, bins=7)+
  scale_fill_manual(values = c("white", "#CEE9e9", "#84BBD8", "#F8F2BE", "#FEC376", "#F88A51", "#A50026"))+
  geom_text(data = state_labels %>% filter(!(region %in% c("massachusetts", "connecticut", "new jersey", "delaware",
                                                           "maryland", "district of columbia", "new hampshire"))), 
            aes(x = long, y = lat, label = word), size =2, inherit.aes = FALSE)+
  geom_text_repel(data = state_labels %>% filter(region %in% c("massachusetts", "connecticut", "new jersey", "delaware",
                                                               "maryland", "district of columbia", "new hampshire")), 
                  aes(x=long, y=lat, label = word), nudge_x = c(5, 3, 5, 4, 5, 4, 4),
                  nudge_y = c(0, 0, -3, 0, 0, 0, 0), size = 2, min.segment.length = 0.2)+
  theme_classic()+
  theme(axis.ticks = element_blank(),
        axis.line = element_blank(),
        axis.text = element_blank(),
        axis.title = element_blank(),
        plot.background = element_blank(),
        panel.background =element_blank())