如何在R中制作美国的基于热度的县地图？

Question

我有美国约1500个县的奶牛数量数据。我想制作一张美国地图，各县以#cows为基础，以阴影加权。 FIPS是与县对应的分数。是否有允许我执行此操作的软件包？

cows alligators  FIPS
4      0 45001
9      1 22001
3      0 51001
113    2 16001
1      0 19001
2      0 29001

Answer 1

作为初学者，牛仔！

## some lonely cows
df<-data.frame(cows=c("4","9","113","1","2"),
           fips =c(45001, 22001, 16001,19001, 29001))

## all Fips
maps::county.fips %>%
  as_tibble %>% 
  extract(polyname, c("region", "subregion"), "^([^,]+),([^,]+)$") ->
  dfips

## some county maps & left_join

map_data("county") %>% 
  left_join(dfips) ->
  data

## more left_join
data<-left_join(data,df)

## character cows
data$cows<-as.numeric(as.character(data$cows))

### more cows
data[["cows"]][is.na(data[["cows"]])] <- 100

## even more random cows

data$cows<-ceiling(rnorm(length(data$cows),600,200))

## map with random, fictive cows
data %>%   ggplot( aes(long, lat, group = group)) +
  geom_polygon(aes(fill=cows)) +
  coord_map() +
  theme_void() +
  scale_fill_viridis_c(option = "A")+
  ggtitle("Fictive random cows of the United States of America", subtitle = "“In a county near YOU!”")