Air distance function in Scala

airDistance

import math._
def airDistance(lat1: Double, lon1: Double, lat2: Double, lon2: Double) = {
  val R = 3958.75
  val dLat = (lat2 - lat1).toRadians
  val dLon = (lon2 - lon1).toRadians
  val a = pow(sin(dLat/2),2) + pow(sin(dLon/2),2) * cos(lat1.toRadians) * cos(lat2.toRadians)
  R * 2 * asin(sqrt(a))
}