How to check if a certain coordinates fall to another coordinates radius using PHP only

Thanks for the help. Below is an example function that takes two sets of longitude and latitude co-ordinates and returns the distance between the two.

function getDistance($latitude1, $longitude1, $latitude2, $longitude2) {    $earth_radius = 6371;  $dLat = deg2rad($latitude2 - $latitude1);    $dLon = deg2rad($longitude2 - $longitude1);    $a = sin($dLat/2) * sin($dLat/2) + cos(deg2rad($latitude1)) * cos(deg2rad($latitude2)) * sin($dLon/2) * sin($dLon/2);    $c = 2 * asin(sqrt($a));    $d = $earth_radius * $c;    return $d;  }$distance = getDistance(56.130366, -106.34677099999, 57.223366, -106.34675644699);if ($distance < 100) {  echo "Within 100 kilometer radius";} else {  echo "Outside 100 kilometer radius";}

You should use Haversine formula to compute distance between two points. You have a PHP version here.

Then just check if distance < 100000.

This should help,

$lat_origin = 56.130366;$long_origin = -106.34677099999;$lat_dest = 57.223366;$long_dest = -106.34675644699;$radius      = 3958;      # Earth's radius (miles, convert to meters)$deg_per_rad = 57.29578;  # Number of degrees/radian (for conversion)$distance = ($radius * pi() * sqrt(            ($lat_origin - $lat_dest)            * ($lat_origin - $lat_dest)            + cos($lat_origin / $deg_per_rad)  # Convert these to            * cos($lat_dest / $deg_per_rad)    # radians for cos()            * ($long_origin - $long_dest)            * ($long_origin - $long_dest)    ) / 180);