[ggplot2, animation] Create animated choropleth map

animated-choropleth.R

rm(list=ls())
toInstall <- c("ggplot2", "maptools", "animation", "rgdal")
lapply(toInstall, library, character.only=TRUE)

# Load and clean World Governance Indicators (WGI) data
# Can be downloaded here https://dl.dropboxusercontent.com/u/18955935/wgi_final.RData
# Most of the cleaning involving matching World Bank naming system with that of the map
load('./data/wgi_cleaned.RData')

# Load world map shape file (Google "TM_WORLD_BORDERS_SIMPL-0.3")
world.map <- readOGR(dsn="./data", layer="TM_WORLD_BORDERS_SIMPL-0.3")
world.ggmap <- fortify(world.map, region = "NAME")

# Check the country names in WGI and world.ggmap and fix the unmatched

# Plot

saveSWF({ # Output a flash
  for (i in c(1996, 1998, 2000, 2002:2011)) {
    temp <- subset(na.omit(wgi[, c('year', 'country', 'cc_est')]), year==i)
    choro <- merge(world.ggmap, temp, by.x="id", by.y="country")
    choro <- choro[order(choro$order), ] # order matters in map data, so we must reorder
    p <- ggplot(data=choro, aes(long, lat, fill=cc_est, group=group))
    print(
      p + geom_polygon() + ylim(c(-60,85)) + # Fix the y-axis range for consistency between the years
        scale_fill_gradient2("Control of\n corruption\n score", limits=c(-2.5,2.5)) + # Use scale_fill_gradient2 for contrast
        labs(title=substitute(paste("Severity of corruption in the world, year ", i), list(i=i)))
    )
  }
}, swf.name="world_corruption.swf", interval=1,
        ani.width=1200, ani.height=600,
        swftools="C:/Program Files (x86)/SWFTools",
         outdir=getwd())

saveLatex({ # Output a pdf that can be embedded in latex documents
  for (i in c(1996, 1998, 2000, 2002:2011)) {
    temp <- subset(na.omit(wgi[, c('year', 'country', 'cc_est')]), year==i)
    choro <- merge(world.ggmap, temp, by.x="id", by.y="country")
    choro <- choro[order(choro$order), ]
    p <- ggplot(data=choro, aes(long, lat, fill=cc_est, group=group))
    print(
      p + geom_polygon() + ylim(c(-60,85)) +
        scale_fill_gradient2("Control of\n corruption\n score", limits=c(-2.5,2.5)) + 
        labs(title=substitute(paste("Severity of corruption in the world, year ", i), list(i=i)))
    )
  }
}, ani.basename = "world_corruption", interval=1,
          ani.width=900, ani.height=450,
          ani.opts="autoplay,loop,controls,width=\\linewidth",
          latex.filename = "world.corruption.tex",
          outdir=getwd())