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 const getKilometrosAprox = (lat1, lon1, lat2, lon2)=>{
   let p = 0.017453292519943295;    // Math.PI / 180
   let c = Math.cos;
   let a = 0.5 - c((lat2 - lat1) * p)/2 +
           c(lat1 * p) * c(lat2 * p) *
           (1 - c((lon2 - lon1) * p))/2;

   return 12742 * Math.asin(Math.sqrt(a)); // 2 * R; R = 6371 km
 }