PHP Math Exercises : Get the distance between two points on the earth

PHP math: Exercise-12 with Solution

Write a PHP function to get the distance between two points on the earth.

Pictorial Presentation:

Sample Solution:

PHP Code:

<?php
// Define a function to calculate the distance between two points given their latitude and longitude
function lat_long_dist_of_two_points($latitudeFrom, $longitudeFrom, $latitudeTo, $longitudeTo){ 
    // Define the value of pi
    $pi = pi(); 

    // Calculate the angular distance between the two points using Haversine formula
    $x = sin($latitudeFrom * $pi/180) * 
         sin($latitudeTo * $pi/180) + 
         cos($latitudeFrom * $pi/180) * 
         cos($latitudeTo * $pi/180) * 
         cos(($longitudeTo * $pi/180) - ($longitudeFrom * $pi/180)); 

    // Calculate the arc tangent
    $x = atan((sqrt(1 - pow($x, 2))) / $x); 

    // Convert the angular distance to kilometers and then to miles
    return abs((1.852 * 60.0 * (($x/$pi) * 180)) / 1.609344); 
} 

// Calculate the distance from New York to London and echo the result
echo lat_long_dist_of_two_points(40.7127, 74.0059, 51.5072, 0.1275).' mi'."\n"; 
?>

Output:

3458.8601748984 mi

Explanation:

In the exercise above,

• function lat_long_dist_of_two_points($latitudeFrom, $longitudeFrom, $latitudeTo, $longitudeTo){: This line defines a function named "lat_long_dist_of_two_points()" which takes four parameters: the latitude and longitude of the first point ('$latitudeFrom', '$longitudeFrom'), and the latitude and longitude of the second point ('$latitudeTo', '$longitudeTo').
• $pi = pi();: This line assigns the value of pi to the variable '$pi'.
• The subsequent lines determine the distance between the two points using the Haversine formula. This is a method used to calculate the distance between two points on a sphere.
• return abs((1.852 60.0 (($x/$pi) * 180)) / 1.609344);: This line calculates the distance between the two points in kilometers using the Haversine formula and converts it to miles.
• echo lat_long_dist_of_two_points(40.7127, 74.0059, 51.5072, 0.1275).' mi'."\n";: This line calls the "lat_long_dist_of_two_points()" function with the latitude and longitude coordinates of New York and London as arguments, calculates the distance between them, and echoes the result in the unit "mi" (miles).

Flowchart :

PHP Code Editor:

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