If-So uses an IP-to-location database in order to get the user's location. Using the geo data as detected by If-So for any reason is possible using the following code:
require_once(IFSO_PLUGIN_BASE_DIR. 'services/geolocation-service/geolocation-service.class.php');
$geo_data = \IfSo\Services\GeolocationService\GeolocationService::get_instance()->get_user_location();
Please bear in mind that IP-to-location services (any service, not just ours) are not 100% accurate. Learn more about IP-to-location services and how they work.