R/population.register.R

In sorvi: sorvi - avoimen datan tyokalupakki

# This file is a part of the soRvi program (http://louhos.github.com/sorvi/)

# Copyright (C) 2010-2012 Louhos <louhos.github.com>. All rights reserved.

# This program is open source software; you can redistribute it and/or modify 
# it under the terms of the FreeBSD License (keep this notice): 
# http://en.wikipedia.org/wiki/BSD_licenses

# This program is distributed in the hope that it will be useful, 
# but WITHOUT ANY WARRANTY; without even the implied warranty of 
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.


#' Retrieve population register data
#'
#' Retrieves municipality data from population register. 
#' TODO: merge with get.municipality.info function
#' The url should be changed when there are updates:
#'
#' @param url String specifying the URL containing the population register data.
#' @return data.frame with municipality information.
#' @export
#' @references
#' See citation("sorvi") 
#' @author Leo Lahti \email{sorvi-commits@@lists.r-forge.r-project.org}
#' @examples # df <- GetPopulationRegister()
#' @keywords utilities

GetPopulationRegister <- function (url = "http://vrk.fi/default.aspx?docid=5127&site=3&id=0") {

  .InstallMarginal("XML")

  # Read tables from the website
  tables <- XML::readHTMLTable(url)

  # Population is in table 4
  pop <- tables[[4]]

  # Preprocess the data
  # Remove Swedish header and summary row
  pop <- pop[-c(1, (nrow(pop):(nrow(pop)-1))),] 

  # Pick informative columns 
  pop <- pop[, c(1, 4, 5, 6)]
  colnames(pop) <- c("Kunta", "Miehet", "Naiset", "Yhteensa")

  # Separate municipality (kunta) code and Finnish/Swedish names
  parser <- function (x) { 
    x <- as.character(x)
    x <- unlist(strsplit(unlist(strsplit(x, "\r\n")), " - "))
    x <- unname(strstrip(x))  
  }
  nimet <- t(sapply(pop[[1]], function (x) {parser(x)}))

  # Convert counts to numeric
  pop <- data.frame(apply(data.frame(pop[, -1]), 2, function (x){as.numeric(as.character(x))}))
  # Store all in data.frame
  df <- data.frame(list(nimet, pop))
  colnames(df)[1:3] <- c("Koodi", "Kunta", "Kommun")

  # Convert municipality names to UTF-8
  rownames(df) <- iconv(as.character(df$Kunta), from = "latin1", to = "UTF-8")

  df

}