Plotting a congressional choropleth map with ggplot and sf

Question

I am struggling to create a congressional heat map using the ggplot2 and sf libraries.

So far I can create blank maps of state congressional districts:

library(ggplot2)
library(fiftystater)
library(colorplaner)
library(USAboundaries)
library(sf)

#This is where I'm pulling congressional district data from 
data('us_congressional')

#Creating dummy data
us_congressional <- us_congressional(resolution = c("low", "high"), states = 
NULL)
us_congressional$dummy <- runif(nrow(dftest), 1, 100)

#Selecting certain states to plot
plot_states_data <- us_congressional(states=c("Maine", "Minnesota", "New 
York", "California", "Montana", "Illinois", "Florida", "Texas"), resolution 
= 'high')

plot(st_geometry(plot_states_data))

I'd like to be able to tie the dummy data to the blank plotted shapes and fill on a gradient - something like this:

#These don't work

ggplot(st_geometry(plot_states_data)) + geom_sf(aes(fill=dummy)) + 
scale_fill_gradient2(low='red',mid = 'white', high = 'blue', midpoint = 50)

# or

plot(st_geometry(plot_states_data)) + geom_sf(aes(fill=dummy)) +
scale_fill_gradient2(low='red',mid = 'white', high = 'blue', midpoint = 50)

But I run into an error: "could not find function "geom_sf"" when using the plot command and this error: "ggplot2 doesn't know how to deal with data of class sfc_MULTIPOLYGON/sfc" when using the ggplot command.

I think the issue is that plot_states_data is both a data frame and sf object class and I am unsure how to either make plot_states_data just a data frame or how to make ggplot and sf work together.

Does anyone have any suggestions on working around these problems?

Edit:

austensen's comment on downloading the developer ggplot2 has solved the problem. For anyone else trying to do the same kind of mapping, this command did the trick for me:

ggplot(plot_states_data) + geom_sf(aes(fill=dummy)) + 
  scale_x_continuous(breaks = NULL) + 
  scale_y_continuous(breaks = NULL) +
  scale_fill_gradientn("Title",
                       colours = c('darkred', 'tomato1', 'cyan2', 
                                   'darkblue'), 
                       values = c(0,.5,.5000001, 1)) + 
  theme(panel.background = element_blank(), axis.ticks = element_blank(), 
        axis.text = element_blank())

Plotting a congressional choropleth map with ggplot and sf

0 Answers