nyt_spiral_animations

  ## Create NYT Spiral Animations
  ## Most Code comes from here: https://bydata.github.io/nyt-corona-spiral-chart/
  
  
  library(tidyverse)
  library(lubridate)
  library(gganimate)
  library(viridis)
  
  owid_url <- "https://github.com/owid/covid-19-data/blob/master/public/data/owid-covid-data.csv?raw=true"
  covid <- read_csv(owid_url)
  
  
  first_rows <- covid %>% 
    distinct(location) %>%
    mutate(date = as_date("2020-01-01"), 
           new_cases = 0,
           new_cases_smoothed = 0,
           new_cases_per_million = 0, 
           new_cases_smoothed_per_million = 0, 
           new_deaths = 0,
           new_deaths_smoothed = 0,
           new_deaths_per_million = 0, 
           new_deaths_smoothed_per_million = 0)
  
  covid_cases <- covid %>% 
    select(date, 
           new_cases,
           new_cases_smoothed,
           new_deaths,
           new_deaths_smoothed,
           new_cases_per_million, 
           new_cases_smoothed_per_million, 
           new_deaths_per_million,
           new_deaths_smoothed_per_million,
           location) %>%
    # Add the dates before the 1st confirmed case
    bind_rows(first_rows) %>% 
    arrange(date) %>% 
    group_by(location) %>% 
    complete(date = seq(min(.$date), max(.$date), by = 1),
             fill = list(new_cases = 0,
                         new_cases_smoothed = 0,
                         new_cases_per_million = 0, 
                         new_cases_smoothed_per_million = 0, 
                         new_deaths = 0,
                         new_deaths_smoothed = 0,
                         new_deaths_per_million = 0, 
                         new_deaths_smoothed_per_million = 0)) %>% 
    mutate(day_of_year = yday(date),
           year = year(date)
    ) %>% 
    ungroup()  %>% 
    # 2020 is a leap year, we could drop Feb 29, 2020 for the sake of 365-day years
    filter(date != as_date("2020-02-29")) %>%
    group_by(year, location) %>%
    mutate(day_of_year = row_number()) %>%
    ungroup() 
  
  saveRDS(covid_cases, file = "data/covid_cases.rds")
  
  
  ##### plot #####
  
  size_factor <- 12000
  
  
  # Colors
  outline_color <- "#D97C86"
  fill_color <- "#F0C0C1"
  base_grey <- "grey28"
  
  
  
  month_length <- c(31, 28, 31, 30, 31, 30,
                    31, 31, 30, 31, 30, 31)
  
  month_breaks <- cumsum(month_length) - 30
  
  p <- covid_cases %>%
    mutate(date2 = date) %>% 
    filter(location == "Netherlands") %>% 
    ggplot() +
    ## I am plotting a ton of lines here because geom_linerange doesn't seem to work
    ## properly with gganimate
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date),
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) - new_cases_smoothed_per_million * size_factor,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) - new_cases_smoothed_per_million * size_factor * 0.9,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) - new_cases_smoothed_per_million * size_factor * 0.8,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) - new_cases_smoothed_per_million * size_factor * 0.70,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) - new_cases_smoothed_per_million * size_factor * 0.6,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) - new_cases_smoothed_per_million * size_factor * 0.5,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) - new_cases_smoothed_per_million * size_factor * 0.4,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) - new_cases_smoothed_per_million * size_factor * 0.3,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) - new_cases_smoothed_per_million * size_factor * 0.2,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) - new_cases_smoothed_per_million * size_factor * 0.1,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) + new_cases_smoothed_per_million * size_factor,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) + new_cases_smoothed_per_million * size_factor * 0.9,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) + new_cases_smoothed_per_million * size_factor * 0.8,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) + new_cases_smoothed_per_million * size_factor * 0.70,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) + new_cases_smoothed_per_million * size_factor * 0.6,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) + new_cases_smoothed_per_million * size_factor * 0.5,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) + new_cases_smoothed_per_million * size_factor * 0.4,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) + new_cases_smoothed_per_million * size_factor * 0.3,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) + new_cases_smoothed_per_million * size_factor * 0.2,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    geom_line(aes(x = day_of_year, 
                  y = as.POSIXct(date) + new_cases_smoothed_per_million * size_factor * 0.1,
                  group = year, color = new_cases_smoothed_per_million), 
              width = 0,
              # color = outline_color, 
              size=1.75, 
              show.legend = T) +
    # annotate("text", label = paste0(year_annotations$year, "\u2192"), x = year_annotations$x, 
    #          y = year_annotations$y, 
    #          family = "Arial",
    #          size = 1, vjust = 1.3, hjust = 0.15) +
    # basic line
    
    scale_x_continuous(minor_breaks = month_breaks, 
                       breaks = month_breaks,
                       labels = c("Jan.", "Feb.", "March", "April", "May", "June", "July", "Aug.", "Sep.", "Oct.", "Nov.", "Dec."),
                       limits = c(1, 365),
                       expand = c(0, 0)
    ) +
    #' set the lower limit of the y-axis to a date before 2020 
    #' so that the spiral does not start in the center point
    scale_y_continuous(limits = c(as.POSIXct("2019-07-01"), NA),
                       expand = c(0, 0)) +
    coord_polar() +
    theme_void()  +
    labs(title = "COVID-19 in the Netherlands",
         subtitle="7-day Average COVID cases per illion people\n",
         caption="Data: Our World in Data | Inspired by: NYT | Initial Code: Ansgar Wolsing (@_ansgar) | Animation: Fabio Votta (@favstats)") +
    theme(
      legend.position = "bottom",
      plot.title = element_text(hjust = 0.5, size = 16),
      plot.subtitle = element_text(hjust = 0.5, size = 7),
      plot.caption = element_text(hjust = 1, size = 3.5),
      plot.background = element_rect(color = NA, fill = "white"),
      panel.grid.major.x = element_line(color = "grey70", size = 0.2, linetype = "dotted"),
      panel.grid.minor.x = element_line(color = "grey70", size = 0.2, linetype = "dotted"),
      axis.text.x = element_text(color = base_grey, size = 5, hjust = 0.5)
    ) +
    viridis::scale_color_viridis(option = "rocket", direction = -1) + 
    guides(color = guide_colourbar(title = "7-day Average COVID cases per million", 
                                   title.vjust = 1,
                                   title.theme = element_text(size = 6.5),
                                   label.theme = element_text(size = 3.5),
                                   barwidth = 5, barheight = 0.5)) +
    transition_reveal(date) +
    ease_aes('linear')
  
  p <- p %>%
    animate(nframes = 300, fps = 20, #duration = 25,
            width = 1000, height = 1000,
            res = 300, end_pause = 60)
  
  anim_save("netherlands.gif", animation = p)