Clearly Demarcating State Boundaries in US County Heatmaps using R Package
In data visualization, it is often crucial to clearly demarcate state boundaries when creating heatmaps for US counties. However, this can sometimes be a challenging task. In this article, we will explore how to create US county heatmaps with clear state boundaries using the R package.
Introduction to the R Package
The R package is a powerful tool for data visualization, providing a wide range of functions and packages for creating high-quality graphics. When it comes to creating heatmaps for US counties, the choroplethr and choroplethrAdmin1 packages are particularly useful. The choroplethr package provides functions for creating choropleth maps, while the choroplethrAdmin1 package adds support for maps of US administrative regions, including counties and states.
Creating a Base Map
To create a base map for our heatmap, we can use the county_choropleth() function from the choroplethr package. This function takes a data frame as input, with one column containing county FIPS codes and another column containing the data to be visualized. In this example, we will use the built-in county\_data dataset from the choroplethr package:
<pre>
# Load the choroplethr package
library(choroplethr)
# Create a base map using the county\_data dataset
county\_map <- county\_choropleth(county\_data,
variable = "poptotal")
# Plot the map
plot(county\_map)
</pre>
This will create a basic choropleth map of US counties, with the color of each county representing the total population:
Adding State Boundaries
To add state boundaries to our heatmap, we can use the add_choropleth_boundaries() function from the choroplethrAdmin1 package. This function takes a choropleth object and an admin1 region ID variable as input, and adds the boundaries for those regions to the map:
<pre>
# Load the choroplethrAdmin1 package
library(choroplethrAdmin1)
# Add state boundaries to the map
state\_boundaries <- add\_choropleth\_boundaries(county\_map,
region = "state")
# Plot the map with state boundaries
plot(state\_boundaries)
</pre>
This will create a heatmap of US counties with clear state boundaries: