Ruby haversine distance method, in miles

geodist.rb

def geodist(a, b)
  rads = Math::PI/180
  # 7926.3352 is diameter of earth in miles
  7926.3352 * Math.asin(
    Math.sqrt(
      Math.sin( (b[1] - a[1])*rads / 2 )**2 *
      Math.cos( a[0] * rads ) *
      Math.cos( b[0] * rads ) +
      Math.sin( (b[0] - a[0])*rads / 2 )**2
    )
  )
end

puts geodist([41.2966716,-96.0750074],[41.133382,-95.96915])