用R画海盗袭击区域的.gif图

摘自 http://www.r-bloggers.com/animated-irl-pirate-attacks-in-r/

在R-blogger看到的一篇用R画.gif动态图的文章，记录下来。

 

library(maps)
library(hexbin)
library(maptools)
library(ggplot2)
library(sp)
library(mapproj)
library('animation')

# 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
# you may need to use a diffeRent name depending on d/l date
pirates.df <- as.data.frame(readShapePoints("ASAM 02 OCT 13.shp")) 

# 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()
}

 

 

如此可以画出35幅.png的静态图，用谢益辉的animation package生成.gif图。

# requires imagemagick
png.name <- sprintf("arrr-%d.png",ends)
im.convert(files=png.name, output = "world.gif", convert = c("convert", "gm convert"),
           cmd.fun = system, extra.opts = "", clean = FALSE)
file.copy(from=paste("C:/Users/~/AppData/Local/Temp/RtmpEvkIWJ", "world.gif", sep="/"), 
        to='D:/R/world.gif', overwrite =T, copy.mode = TRUE)