Animated Cartogram of the Nov 2022 Georgia Senate election

walkerwarnock_2022.csv

walkerwarnock_animatedcartogram.R

library(tidyverse)
library(cartogram)
library(sf)
library(tmap)
library(gganimate)
library(tweenr) 
library(transformr)
library(gifski)

#Set color scheme and get county boundaries
pal<-c("#4175b5","#b8cae0","#f2f7f3","#e38a84","#a11208")
ga_cty<-tigris::counties(state="GA")

#Read and clean election data
#Downloaded from Georgia Secretary of State and saved the senate tab
election1<-read_csv("walkerwarnock_2022.csv")[1,] %>%
  pivot_longer(3:18,names_to="var1",values_to="values1") %>%
  select(4) %>%
  fill(values1)
election2<-read_csv("walkerwarnock_2022.csv",skip=2) %>%
  pivot_longer(`Election Day Votes...3`:Total,names_to="vars",values_to="values") 

#Two row headers, so combined those
names1<-paste(election2$vars,election1$values1)

election2$fullname<-names1

election<-election2 %>%
  select(-vars) %>%
  filter(str_detect(fullname,"Total")) %>%
  pivot_wider(names_from=fullname,values_from="values") 

#Make the names shorter
names(election)<-c("county","voters","walker_tot","warnock_tot","oliver_tot","total")

#Calculate rates
election<-election %>%
  mutate(pct_walker=walker_tot/total*100,
         pct_warnock=warnock_tot/total*100)

#Join to sf data
election_sf<-ga_cty %>%
  rename(county=NAME) %>%
  left_join(election) %>%
  st_transform(32616)

#Create the cartogram based on total votes
ga_carto<-cartogram_cont(election_sf,"total",itermax=7)
tm_shape(ga_carto)+tm_borders()

# Calculate the transition between these 2 objects
dt <- tween_sf(election_sf,ga_carto,ease='cubic-in-out', nframes = 50)

#Create a function to plot the data in tmap
sfplot <- function(frame_sel) {
  data_map<-dt %>% 
    filter(.frame==frame_sel) %>%
    st_as_sf()
  
  p <- tm_shape(data_map)+
    tm_polygons("pct_walker",breaks=c(0,30,45,55,70,100),palette=pal,
                title="Pct. voting for Walker")+
    tm_layout(main.title="Nov. 2022 Senate election in Georgia",
              frame=FALSE,
              main.title.position = "center")+
    tm_legend(position = c(0.7,0.8))+
    tm_credits("Data: Georgia SOS | Map by @jerry_shannon",
               position=c("left","bottom"),
               size=0.9)
  tmap_save(p,paste("election_map/election_frame_",str_pad(frame_sel,2,pad=0),".png",sep=""))
}

#Calculate the number of frames and save jpg versions
#sfplot(40)
frames<-unique(dt$.frame)

map(frames,sfplot)

#Create a gif with gifski
files<-list.files(path="election_map",full.names = TRUE)
files1<-rev(files) #Reverse the order to go back
files2<-c(files,files1) #Combine the lists
gifski(files2,gif_file="warnockwalker.gif",loop=TRUE,delay=0.1,width=664,height=737)