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Avast me hearRties! (ok, enough of the pirate speak in a blog post)

It wouldn’t be TLAPD without out some modest code & idea pilfering from Mark Bulling & Simon Raper. While those mateys did a fine job hoisting up some R code (your really didn’t think I’d stop with the pirate speak, did you?) for their example, I took it one step furrrrther to build an animation of cumulative, yearly IRL pirate attacks from 1978 to the present. I found it a bit interesting to see how the hotspots shifted over time. Click on the graphic for the largeR version or I’ll make ye walk the plank!!.

```library(maps) library(hexbin) library(maptools) library(ggplot2) library(sp) library(mapproj)   # piRate the data from the militaRy download.file("http://msi.nga.mil/MSISiteContent/StaticFiles/Files/ASAM_shp.zip", destfile="ASAM_shp.zip") unzip("ASAM_shp.zip")   # extRact the data fRame we need fRom the shape file pirates.df <- as.data.frame(readShapePoints("ASAM 19 SEP 13")) # you may need to use a diffeRent name depending on d/l date   # get the woRld map data world <- map_data("world") world <- subset(world, region != "Antarctica") # inteRcouRse AntaRctica   # yeaRs we want to loop thoRugh ends <- 1979:2013   # loop thRough, extRact data, build plot, save plot: BOOM for (end in ends) { png(filename=sprintf("arrr-%d.png",end),width=500,height=250,bg="white") # change to 1000x500 or laRgeR dec.df <- pirates.df[pirates.df\$DateOfOcc > "1970-01-01" & pirates.df\$DateOfOcc < as.Date(sprintf("%s-12-31",end)),] rng <- range(dec.df\$DateOfOcc) p <- ggplot() p <- p + geom_polygon(data=world, aes(x=long, y=lat, group=group), fill="gray40", colour="white") p <- p + stat_summary_hex(fun="length", data=dec.df, aes(x=coords.x1, y=coords.x2, z=coords.x2), alpha=0.8) p <- p + scale_fill_gradient(low="white", high="red", "Pirate Attacks recorded") p <- p + theme_bw() + labs(x="",y="", title=sprintf("Pirate Attacks From %s to %s",rng[1],rng[2])) p <- p + theme(panel.background = element_rect(fill='#A6BDDB', colour='white')) print(p) dev.off() }   # requires imagemagick system("convert -delay 45 -loop 0 arrr*g arrr500.gif")```