Gera valor de latitude e longitude até uma determinada distância de um ponto inicial.

randomLatitudeLongitude.php

<?php

$randomCoordinated = function($x0, $y0, $radius){
    $randomFloat = function($min = 0, $max = 1) {
        return $min + mt_rand() / mt_getrandmax() * ($max - $min);
    };

    // Convert radius from meters to degrees
    $radiusInDegrees = $radius / 111000;

    $u = $randomFloat();
    $v = $randomFloat();
    $w = $radiusInDegrees * sqrt($u);
    $t = 2 * pi() * $v;
    $x = $w * cos($t);
    $y = $w * sin($t);

    // Adjust the x-coordinate for the shrinking of the east-west distances
    $new_x = $x / cos($y0);

    $foundLongitude = $new_x + $x0;
    $foundLatitude = $y + $y0;
    

    $object = new StdClass();
    $object->lat = $foundLongitude;
    $object->lng = $foundLatitude;
    return $object;
};

// Usage:
// Ex: Algum ponto em Florianópolis.
$randomLatitude = $randomCoordinated(-27.59465, -48.53699, 2000);