在R中使用ggmaps、maps和ggplot2制作突出显示特定县和点的州地图。

Question

我正在尝试构建一个州地图，其中各县已轮廓化，并且其中一个县被涂成蓝色，同时标出一个特定度假村的位置。不幸的是，我无法将县染色或添加特定点。我的代码基于http://eriqande.github.io/rep-res-web/lectures/making-maps-with-R.html。感谢您的任何见解！

library(ggplot2)
library(ggmap)
library(maps)
library(mapdata)    

states <- map_data("state")
dim(states)
ut_df <- subset(states, region == "utah")
head(ut_df)

counties <- map_data("county")
ut_county <- subset(counties, region == "utah")
head(ut_county)

ut_base <- ggplot(data = ut_df, mapping = aes(x = long, y = lat, group = 
group)) +
coord_fixed(1.3) +
geom_polygon(color = "black", fill = "gray")

ut_base + theme_nothing() +
geom_polygon(data = ut_county, fill = NA, color = "white") +
geom_polygon(color = "black", fill = NA)  # get the state border back on top

- James

Answer 1

# Select a subregion
single_county <- subset(ut_county, subregion=="utah")

# Fill the selected subregion with a predefined color and
# plot a colored point with a specified long. and lat.
ut_base + theme_void() +
geom_polygon(data = ut_county, fill = NA, color = "white") +
geom_polygon(color = "black", fill = NA) +
geom_polygon(data = single_county, fill = "red", color = "white") +
geom_point(x=-111.8, y=40.2, col="blue", size=3)

- Marco Sandri

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谢谢！这正是我想要做的 :) - James