﻿ Java - Distance between two points on the surface of earth

# Java: Compute the distance between two points on the surface of earth

## Java Basic: Exercise-36 with Solution

Write a Java program to compute the distance between two points on the earth's surface.

Distance between the two points [ (x1,y1) & (x2,y2)]
d = radius * arccos(sin(x1) * sin(x2) + cos(x1) * cos(x2) * cos(y1 - y2))
Radius of the earth r = 6371.01 Kilometers

Test Data:
Input the latitude of coordinate 1: 25
Input the longitude of coordinate 1: 35
Input the latitude of coordinate 2: 52.5
Input the longitude of coordinate 2: 35.5

Pictorial Presentation:

Sample Solution:

Java Code:

``````import java.util.Scanner;

public class Exercise36 {

public static void main(String[] args) {
Scanner input = new Scanner(System.in);

// Prompt the user to input the latitude and longitude of coordinate 1
System.out.print("Input the latitude of coordinate 1: ");
double lat1 = input.nextDouble();
System.out.print("Input the longitude of coordinate 1: ");
double lon1 = input.nextDouble();

// Prompt the user to input the latitude and longitude of coordinate 2
System.out.print("Input the latitude of coordinate 2: ");
double lat2 = input.nextDouble();
System.out.print("Input the longitude of coordinate 2: ");
double lon2 = input.nextDouble();

// Calculate and display the distance between the two coordinates
System.out.print("The distance between those points is: " + distance_Between_LatLong(lat1, lon1, lat2, lon2) + " km\n");
}

// Points will be converted to radians before calculation
public static double distance_Between_LatLong(double lat1, double lon1, double lat2, double lon2) {
// Convert latitude and longitude to radians

// Earth's mean radius in kilometers

// Calculate the distance using the haversine formula
return earthRadius * Math.acos(Math.sin(lat1) * Math.sin(lat2) + Math.cos(lat1) * Math.cos(lat2) * Math.cos(lon1 - lon2));
}
}
```
```

Explanation:

In the exercise above -

• First, it uses the "Scanner" class to obtain user input.
• The user is prompted to input the latitude and longitude of two coordinates:
• Latitude and longitude of coordinate 1 are read into the variables 'lat1' and 'lon1'.
• Latitude and longitude of coordinate 2 are read into the variables 'lat2' and 'lon2'.
• The code then calls a separate method named "distance_Between_LatLong()" and passes the latitude and longitude values of both coordinates as arguments.
• Inside the "distance_Between_LatLong()" method:
• It converts latitude and longitude values from degrees to radians using the "Math.toRadians()" method to perform trigonometric calculations.
• It calculates the distance between the two coordinates using the Haversine formula for calculating distances on a sphere.
• The calculated distance is returned as a double, representing the distance in kilometers.
• Finally, in the "main() method, the result of the "distance_Between_LatLong()" method is printed, displaying the distance between the two coordinates in kilometers.

Sample Output:

```Input the latitude of coordinate 1: 25
Input the longitude of coordinate 1: 35
Input the latitude of coordinate 2: 52.5
Input the longitude of coordinate 2: 35.5
The distance between those points is: 3058.15512920181 km
```

Flowchart:

Java Code Editor:

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