Extending plot_usmap with ggplot2
The nice thing about usmap::plot_usmap is it returns a ggplot object object, which means we can add ggplot layers to the plot right out of the box.
library(usmap)
library(ggplot2)
plot_usmap(regions = "counties") +
labs(title = "US Counties",
subtitle = "This is a blank map of the counties of the United States.") +
theme(panel.background = element_rect(color = "black", fill = "lightblue"))
Plot only certain states
library(usmap)
library(ggplot2)
plot_usmap(include = c("CA", "ID", "NV", "OR", "WA")) +
labs(title = "Western US States",
subtitle = "These are the states in the Pacific Timezone.")
Add some data to the map
library(usmap)
library(ggplot2)
plot_usmap(data = statepop, values = "pop_2015", color = "red") +
scale_fill_continuous(name = "Population (2015)", label = scales::comma) +
theme(legend.position = "right")
Notice the comprehensive expandability that can be applied to the map using ggplot2 layers. For example, we might want to use a different color scheme.
Change fill color scale
library(usmap)
library(ggplot2)
plot_usmap(data = statepop, values = "pop_2015", color = "red") +
scale_fill_continuous(
low = "white", high = "red", name = "Population (2015)", label = scales::comma
) + theme(legend.position = "right")
The data-filled map can also be filtered to show certain regions only, like the western states shown above.
Show data in certain states
library(usmap)
library(ggplot2)
plot_usmap(
data = statepop, values = "pop_2015", include = c("CA", "ID", "NV", "OR", "WA"), color = "red"
) +
scale_fill_continuous(
low = "white", high = "red", name = "Population (2015)", label = scales::comma
) +
labs(title = "Western US States", subtitle = "These are the states in the Pacific Timezone.") +
theme(legend.position = "right")
Required Data Format
The data passed to the data parameter in plot_usmap() must be a data frame with at least two columns. One of the columns must be named "fips" or "state" and contain either the FIPS code, the state abbreviation, or the state name (for county maps only the FIPS code is supported). The second column must be the values to be plotted for each region. The default name of the values column is "values". If a different name is used in the data frame, the name can be specified in the values parameter of plot_usmap. Any extra columns in the data frame will be ignored.
FIPS column with default values column
df <- data.frame(
fips = c("02", "01", "05", "04"),
values = c(14, 18, 19, 8)
)
plot_usmap(data = df)FIPS column with custom values column
Name of values column must be specified in values parameter if it is not "values".
df <- data.frame(
fips = c("02", "01", "05", "04"),
population = c(14, 18, 19, 8)
)
plot_usmap(data = df, values = "population")States
Abbreviations and full names can be mixed if desired.
df <- data.frame(
state = c("AL", "Alaska", "AR", "AZ"),
values = c(14, 18, 19, 8)
)
plot_usmap(data = df)Counties
County names are not supported in plot_usmap data frames. Use fips instead.
df <- data.frame(
fips = c("10001", "10003", "10005"),
values = c(93, 98, 41)
)
plot_usmap(data = df)
