在州名称上显示与美国各州对应的值

Question

我试图使用包 "choroplethr" 和一个简单的 df2 数据集（它具有相同的区域和值列）创建美国各州地图，并且我使用了包文档中提供的代码。

require (choroplethr)

data("df_pop_state")

df2 <- read.csv("ShareDF-chro.csv", header=TRUE, stringsAsFactors=FALSE)



# here is the data ShareDF-chro

region = c("alabama", "alaska", "arizona", "arkansas", 
"california", "colorado", "connecticut", "delaware", "district of columbia", 
"florida", "georgia", "hawaii", "idaho", "illinois", "indiana", 
"iowa", "kansas", "kentucky", "louisiana", "maine", "maryland", 
"massachusetts", "michigan", "minnesota", "mississippi", "missouri", 
"montana", "nebraska", "nevada", "new hampshire", "new jersey", 
"new mexico", "new york", "north carolina", "north dakota", "ohio", 
"oklahoma", "oregon", "pennsylvania", "rhode island", "south carolina", 
"south dakota", "tennessee", "texas", "utah", "vermont", "virginia", 
"washington", "west virginia", "wisconsin", "wyoming"), 

value = c(1.15, 0.11, 6.21, 2.41, 8.42, 13.57, 3.57, 4.55, 7.08, 9.42, 5.21, 
0.108, 9.09, 2.56, 4.51, 9.65, 6.76, 3.54, 0.17, 1.99, 6.66, 
3.88, 7.31, 4.86, 4.85, 2.39, 0.25, 0.05, 0.21, 0.11, 3.86, 0.05, 
7.31, 1.91, 0.41, 4.55, 0.002, 2.65, 3.14, 0.71, 1.94, 0.13, 
2.2, 12.65, 0.05, 0.074, 5.79, 7.5, 0.12, 2.6, 0.33)

df_pop_state$value <- df2$value

state_choropleth(df_pop_state,title = "US State's X-Capital share data",num_colors = 2,legend = "Capital Share")

我的问题是：如何在地图中插入相应的 X-capital 份额值以及州的首字母缩写词（同时希望首字母缩写词的字体大小更小）。谢谢，非常感谢您的帮助。

Answer 1

这里是 ggplot2 的解决方案。

用usmap::us_map获取多边形数据。（和你一样）
左加入您的共享数据（首先将您的地区名称大写）
Create centroids for the text annotation。
那些质心和份额最好放在一个单独的数据框中
使用 geom_polygon
使用粘贴 geom_text 绘制标签（国家缩写和分享）。（您也可以使用 annotate）
将数据分别传递给每一层。（清空 ggplot 主调用）

优点是 ggplot 语法的使用使颜色/填充美学的控制变得非常容易，您还可以非常轻松地自定义线条粗细和文本大小。

关于州的缩写，我只用了第一个到字母——这可能不是官方缩写。肯定有一些矢量可以轻松转换它。

library(usmap)
library(tidyverse)

us <- usmap::us_map()

region <- str_to_title(region)

share_df <- data.frame(region, share)

us_val <- 
  left_join(us, share_df, by = c("full" ="region")) 
#> Warning: Column `full`/`region` joining character vector and factor, coercing
#> into character vector

us_centroids <- 
  us_val %>%
  group_by(full) %>% 
  summarise(centroid.x = mean(range(x)), 
            centroid.y = mean(range(y)),
            label = unique(toupper(str_sub(full,1,2))),
            share = unique(share))

ggplot() + 
  geom_polygon(data = us_val, 
               aes(x,y, group = group, fill = share > 3), 
               color = "black",
               size = .1) +
  geom_text(data = us_centroids, 
            aes(centroid.x, centroid.y, label = paste(label, "\n", share)),
            size = 5/14*8) +
  scale_fill_brewer(name = "State Share", 
                    palette = "Blues", 
                    labels = c(`TRUE`="More than 3",`FALSE`="Less than 3")) +
  theme_void()

^{由 reprex package (v0.3.0)}

于 2020-05-06 创建

更新用缩写说了这一点 - 查看 ?datasets::state。它包含那些缩写 (state.abb) 和州名 (state.name)。它还包含有关质心的数据 (state.center)。所以，很多数据已经内置:)

数据

region =  c("alabama", "alaska", "arizona", "arkansas", 
           "california", "colorado", "connecticut", "delaware", "district of columbia", 
           "florida", "georgia", "hawaii", "idaho", "illinois", "indiana", 
           "iowa", "kansas", "kentucky", "louisiana", "maine", "maryland", 
           "massachusetts", "michigan", "minnesota", "mississippi", "missouri", 
           "montana", "nebraska", "nevada", "new hampshire", "new jersey", 
           "new mexico", "new york", "north carolina", "north dakota", "ohio", 
           "oklahoma", "oregon", "pennsylvania", "rhode island", "south carolina", 
           "south dakota", "tennessee", "texas", "utah", "vermont", "virginia", 
           "washington", "west virginia", "wisconsin", "wyoming")

share = c(1.15, 0.11, 6.21, 2.41, 8.42, 13.57, 3.57, 4.55, 7.08, 9.42, 5.21, 
          0.108, 9.09, 2.56, 4.51, 9.65, 6.76, 3.54, 0.17, 1.99, 6.66, 
          3.88, 7.31, 4.86, 4.85, 2.39, 0.25, 0.05, 0.21, 0.11, 3.86, 0.05, 
          7.31, 1.91, 0.41, 4.55, 0.002, 2.65, 3.14, 0.71, 1.94, 0.13, 
          2.2, 12.65, 0.05, 0.074, 5.79, 7.5, 0.12, 2.6, 0.33)

在州名称上显示与美国各州对应的值

Display values corresponding to the USA states over the state name

maps

r

ggplot2

choropleth

choroplethr