elevation_of を使って 3D GeoJSON を作成するスクリプト ref: http://qiita.com/handygeospatial/items/aa9175bd3014acc84209

file0.rb

require 'json'
require './elevation_of.rb'

data = JSON.parse(File.open('kyogatake.geojson').read)

a = data['features'][0]['geometry']['coordinates']
a.each_index {|i|
  a[i] << elevation_of(a[i][0], a[i][1])
}

File.open('kyogatake3d.geojson', 'w') {|w|
  w.print JSON.dump(data)
}