Clever Geek Handbook

How to calculate the difference between longitudes?

I need to calculate the difference between the longitude and latitude of the current position
and the previous position. but it displays the result in exponential format and I need it in
meters. I don't understand how to convert it to counter format. What formula does this require?

double distance2 = distanceCalculate(lat,lng,locationB.getLatitude(),locationB.getLongitude());
Toast.makeText(this, "distance2=="+Double.valueOf(distance2).longValue() + "meter" , Toast.LENGTH_SHORT).show(); 

double ActualDistance=(Double.valueOf(distance2).longValue())/1E6;
if(ActualDistance<400)
{
    System.out.println("identical");
    Toast.makeText(this,"identical", Toast.LENGTH_LONG).show();
}
else
{
    // send sms
    SmsManager sms = SmsManager.getDefault();
}

public static float distanceCalculate (double lat1, double lng1, double lat2, double lng2 ) 
{
      double earthRadius = 3958.75;
      double dLat = Math.toRadians(lat2-lat1);
      double dLng = Math.toRadians(lng2-lng1);
      double a = Math.sin(dLat/2) * Math.sin(dLat/2) +
      Math.cos(Math.toRadians(lat1)) * Math.cos(Math.toRadians(lat2)) *
      Math.sin(dLng/2) * Math.sin(dLng/2);
      double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a));
      double dist = earthRadius * c;

      int meterConversion = 1609;

      return new Float(dist * meterConversion).floatValue();
}
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3 answers


I find this in JavaScript, I think it might help you figure out how you can do this



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It's simple - you are currently using the Earth's radius in miles; just change the radius value in meters ( per Wikipedia : 6,371,000) and remove the conversion



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In this question I found this code:

public static double distFrom(double lat1, double lng1, double lat2, double lng2) { 
  double earthRadius = 3958.75; 
  double dLat = Math.toRadians(lat2-lat1); 
  double dLng = Math.toRadians(lng2-lng1); 
  double a = Math.sin(dLat/2) * Math.sin(dLat/2) + 
           Math.cos(Math.toRadians(lat1)) * Math.cos(Math.toRadians(lat2)) * 
           Math.sin(dLng/2) * Math.sin(dLng/2); 
  double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
  double dist = earthRadius * c; 

  return dist; 
}

This is a java implementation of Haversine .

It will return the distance in miles. For other units, change the earthRadius value with http://en.wikipedia.org/wiki/Earth_radius

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