javascript里程计算

function calculateDistance(lat1, lon1, lat2, lon2) {
  const earthRadius = 6371; // 地球半径，单位为千米

  const dLat = toRadians(lat2 - lat1);
  const dLon = toRadians(lon2 - lon1);

  const a =
    Math.sin(dLat / 2) * Math.sin(dLat / 2) +
    Math.cos(toRadians(lat1)) * Math.cos(toRadians(lat2)) *
    Math.sin(dLon / 2) * Math.sin(dLon / 2);

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

  const distance = earthRadius * c; // 距离，单位为千米
  return distance;
}

function toRadians(degrees) {
  return degrees * (Math.PI / 180);
}

// 示例用法
const distance = calculateDistance(40.7128, -74.0060, 34.0522, -118.2437);
console.log(distance); // 输出结果：3934.86 千米