Color an SVG Map of the United States with Data

gen3.rb

#!/usr/bin/env ruby

require 'carmen'
require 'nokogiri'

nok = Nokogiri::XML(File.open("usmap.svg"))

states = {}
max = 0
min = 99999
File.open("unemployment.tsv").each_line do |l|
  next if l =~ /^Rank/
  l.chomp!
  row = l.split("\t")
  state = row[1]
  abbv = Carmen::state_code(state)
  next if abbv == nil
  states[abbv] = row[2].to_f
  max = states[abbv] if states[abbv] > max
  min = states[abbv] if states[abbv] < min
end

max = max - min
states.each_key do |abbv|
  pct = (states[abbv] - min) / max.to_f
  amount = (255 * pct)
  blue = "%02x" % amount
  color = "0000#{blue}"
  nok.xpath("//*[@id='#{abbv}']").each do |obj|
    style = obj.attr('style')
    style.gsub!(/fill:#(?:[A-Fa-f0-9][A-Fa-f0-9]){3}/, "fill:##{color}")
    obj.set_attribute('style', style)
    obj.children.each do |chld|
      style = obj.attr('style')
      style.gsub!(/fill:#(?:[A-Fa-f0-9][A-Fa-f0-9]){3}/, "fill:##{color}")
      obj.set_attribute('style', style)
    end
  end
end

File.open('unemployment.svg','w') {|f| nok.write_xml_to f}