Code to create a map of MA COVID-19 cases-per-capita per day for the 30 Day Map Challenge

covid.R

library(sf)
library(dplyr)
library(tidyr)
library(lubridate)
library(readr)
library(ggplot2)
library(tidycensus)

cases <- read_csv("https://raw.githubusercontent.com/CSSEGISandData/COVID-19/master/csse_covid_19_data/csse_covid_19_time_series/time_series_covid19_confirmed_US.csv") %>%
  pivot_longer(cols = matches("^\\d.*"), names_to = "Date", values_to = "cumulative") %>%
  mutate(Date = as_date(Date, format = "%m/%d/%y", tz = "America/New_York")) %>%
  group_by(Province_State, Admin2) %>%
  filter(max(cumulative) > 0) %>%
  arrange(Province_State, Admin2, Date) %>%
  mutate(daily = cumulative - lag(cumulative, 1L, 0))

county_2018 <- get_acs("county", "B01003_001", geometry = TRUE, state = "MA")

if (!dir.exists("25covid")) dir.create("25covid")

map_data <- cases %>%
  filter(Province_State == "Massachusetts") %>% 
  group_by(Date, FIPS) %>%
  summarise(daily = sum(daily)) %>%
  ungroup() %>%
  mutate(FIPS = as.character(FIPS)) %>% 
  inner_join(county_2018, by = c("FIPS" = "GEOID")) %>% 
  mutate(value = daily / estimate,
         value = ifelse(value < 0, 0, value))

date_seq <- seq(as_date('2020-03-01'), max(map_data$Date), 1)
map_range <- range(map_data$value)

for (i in seq_len(length(date_seq))) {
  map_data %>% 
    filter(Date == date_seq[[i]]) %>% 
    ggplot() + 
    geom_sf(aes(geometry = geometry, fill = value), color = "#ffffcc") + 
    scale_fill_distiller(palette = "YlOrRd", 
                         direction = 1, 
                         limits = map_range) + 
    coord_sf() + 
    labs(caption = date_seq[[i]]) +
    theme_void() %+replace%
    theme(legend.position = "none",
          panel.background = element_rect(fill = "#202020"),
          plot.caption = element_text(hjust = 0.05),
          plot.caption.position = "plot") + 
    ggsave(paste0("25covid/", date_seq[[i]], ".png"), width = 11, height = 5)
}

# And an imagemagick command to make the movie...
paste0("convert -delay 50 -limit memory 3000MB ",
       paste0("25covid/",
              list.files("25covid"),
              collapse = " "),
       " 25covid/map.mp4")