location_search.php

<?php

function distance($lat1, $lng1, $lat2, $lng2)
{
    // convert latitude/longitude degrees for both coordinates
    // to radians: radian = degree * π / 180
    $lat1 = deg2rad($lat1);
    $lng1 = deg2rad($lng1);
    $lat2 = deg2rad($lat2);
    $lng2 = deg2rad($lng2);

    // calculate great-circle distance
    $distance = acos(sin($lat1) * sin($lat2) + cos($lat1) * cos($lat2) * cos($lng1 - $lng2));

    // distance in human-readable format:
    // earth's radius in km = ~6371
    return 6371 * $distance;
}


function search()
{
      // we'll want everything within, say, 10km distance
    $distance = 10;

// earth's radius in km = ~6371
    $radius = 6371;

    $lat = 60.494717;
    $lng = -151.06813;

// latitude boundaries
    $maxlat = $lat + rad2deg($distance / $radius);
    $minlat = $lat - rad2deg($distance / $radius);

// longitude boundaries (longitude gets smaller when latitude increases)
    $maxlng = $lng + rad2deg($distance / $radius / cos(deg2rad($lat)));
    $minlng = $lng - rad2deg($distance / $radius / cos(deg2rad($lat)));

    $jewel = \DB::connection('jewel');

    $stores = $jewel->table('wp_blue_stores')->whereBetween('lat', [
        $minlat,
        $maxlat
    ])->whereBetween('long', [$minlng, $maxlng])->get();

    $result = $stores->pluck('account_id')->toArray();

    foreach ($stores as $index => $store) {
        $resultDistance = distance($lat, $lng, $store->lat, $store->long);

        if ($resultDistance > $distance) {
            unset($stores[$index]);
        }
    }

    dd($stores->pluck('account_id')->toArray(), $result);
}

// Reference: https://www.mullie.eu/geographic-searches/