Number years cities are hosting a CRAN mirror

gistfile1.r

## Copyright Markus Gesmann, March 2011
## Distributed under GPL 2 or later
## Since version R-2.0.1 the doc directory includes a list of CRAN mirrors
library(googleVis)
library(XML)
r.tags  <- readLines("http://svn.r-project.org/R/tags/")
r.tags <- r.tags[grep("R-2-",r.tags)]
r.versions <- sapply( strsplit(r.tags, "[< >]", perl=TRUE), '[', 8)
r.sources <- sub("/", ".tar.gz", sub("_", "-", gsub("-", ".", sub("-", "_", r.versions))))
r.svn.history <- data.frame(r.versions, r.sources) 

y=readHTMLTable(readLines("http://cran.r-project.org/src/base/R-2/"), which=1)

R.2_history <- merge(r.svn.history, y, by.x="r.sources", by.y="Name")
R.2_history$Year <-  format(as.POSIXct(as.character(
                            R.2_history[,"Last modified"]),
                            format="%d-%b-%Y %H:%M"),
                            "%Y")

cran.mirror.history <- 
  sapply(r.versions[-1], function(i){
    cran.file <-
      paste("http://svn.r-project.org/R/tags/",i,"doc/CRAN_mirrors.csv",
            sep="")   
    read.csv(cran.file)
  }
         )

cran.cities.by.R.version <- sapply(sapply(cran.mirror.history, "[[", "City"), unique)

cran.cities.by.R.version <- do.call("rbind",
                                    lapply(names(cran.cities.by.R.version), function(x)                                                           
                                           data.frame(Version=x,
                                                      City=cran.cities.by.R.version[[x]])))

cran.cities.by.R.version <- merge(R.2_history[c("r.versions", "Year")],
                                  cran.cities.by.R.version,
                                  by.x="r.versions", by.y="Version")

cran.cities.years <-
  as.data.frame(apply(table(unique(
                                   cran.cities.by.R.version[c("Year", "City")]
                                   )),
                      2, sum))

cran.cities.years$City <- rownames(cran.cities.years)
names(cran.cities.years) <- c("Years.hosting.CRAN.mirror", "City")

Chart.Cran.Cities <- gvisGeoChart(cran.cities.years, "City",
                                  "Years.hosting.CRAN.mirror",
                                  options=list( displayMode="markers",
                                    markerOpacity=0.5,
                                    sizeAxis="{minValue: 0,  maxSize: 15}"),
                                  chartid="CRAN_Mirror_Cities")

plot(Chart.Cran.Cities)