ionic3 – คำนวณระยะทางระหว่างจุด 2 จุด (latitude-longitude points)

The Haversine Formula

พารามิเตอร์

lat1, lon1: The Latitude and Longitude of point 1 (in decimal degrees)
lat2, lon2: The Latitude and Longitude of point 2 (in decimal degrees)

  toRad(value) {
    var RADIANT_CONSTANT = 0.0174532925199433;
    return (value * RADIANT_CONSTANT);
  }

  calculateDistance(lat1, lng1, lat2, lng2) {
    var KM_RATIO = 6371;
    try {
      var dLat = this.toRad(lat2 - lat1);
      var dLon = this.toRad(lng2 - lng1);
      var lat1Rad = this.toRad(lat1);
      var lat2Rad = this.toRad(lat2);

      var a = Math.sin(dLat / 2) * Math.sin(dLat / 2) +
        Math.sin(dLon / 2) * Math.sin(dLon / 2) * Math.cos(lat1Rad) * Math.cos(lat2Rad);
      var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));

      return KM_RATIO * c * 1000;
    } catch (e) {
      return -1;
    }
  }

toRad(value) {

var RADIANT_CONSTANT = 0.0174532925199433;

return (value * RADIANT_CONSTANT);

}

calculateDistance(lat1, lng1, lat2, lng2) {

var KM_RATIO = 6371;

try {

var dLat = this.toRad(lat2 - lat1);

var dLon = this.toRad(lng2 - lng1);

var lat1Rad = this.toRad(lat1);

var lat2Rad = this.toRad(lat2);

var a = Math.sin(dLat / 2) * Math.sin(dLat / 2) +

Math.sin(dLon / 2) * Math.sin(dLon / 2) * Math.cos(lat1Rad) * Math.cos(lat2Rad);

var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));

return KM_RATIO * c * 1000;

} catch (e) {

return -1;

}

Link

Calculating distance and speed with the GeoLocation API – PhoneGap (Part 9).

Phaisarn Sutheebanjard

blog.phaisarn.com

ionic3 – คำนวณระยะทางระหว่างจุด 2 จุด (latitude-longitude points)