Convert JPS format to ascii text.

jps2text.rb

#!/usr/bin/ruby

require "rexml/parsers/streamparser"
require "rexml/parsers/baseparser"
require "rexml/streamlistener"

class JPS2TextListener
  include REXML::StreamListener
  
  def initialize
    @id = -1
    @alti = lambda{|val| 
      pos = calcLatLng(@id+=1)
      print pos[0], " ", pos[1] ," ",val,"\n"
    }
    @func = nil
  end
  
  def tag_start(name, attrs)
    case name
    when "alti" then
      @func = @alti
    when "jps:westBoundLongitude" then
      @func = lambda{|val| @west = val.to_f}
      
    when "jps:eastBoundLongitude" then
      @func = lambda{|val| @east = val.to_f}
      
    when "jps:southBoundLatitude"
      @func = lambda{|val| @south = val.to_f}
      
    when "jps:northBoundLatitude"
      @func = lambda{|val| @north = val.to_f}

    when "jps:high"
      @high = true

    when "jps:low"
      @low = true

    when "jps:coordValues"
      @func = lambda{|val| 
        if @high == true
          @high = [val.split[0].to_f, val.split[1].to_f] 
        else
          @low = [val.split[0].to_f, val.split[1].to_f]
        end
      }
    end
  end
  
  def tag_end(name)
    @func = nil
    
    if name === "jps:extent"
      @dx = (@east - @west) / (@high[0] - @low[0])
      @dy = (@south - @north) / (@high[1] - @low[1])
      @nx = @high[0] - @low[0] + 1
    end
  end
  
  def text(val)
    unless @func == nil
      @func.call val
    end
  end

  def calcLatLng(i)
    lng = sprintf("%.9f", (@west + @dx * (i % @nx)))
    lat = sprintf("%.9f", (@north + @dy * ((i / @nx).truncate)))
    return [lat, lng]
  end
end


def main
  if ARGV.size == 0
    puts "Usage: ruby jps2text.rb JPSFileName"
    return 
  end

  xml = File.open(ARGV[0])
  parser = REXML::Parsers::StreamParser.new(xml, JPS2TextListener.new)
  
  puts parser.parse
end


main