How can I stop the users from accessing the map without sign in?

The GPS tracking app has a direct link to the online map page, which usually requires a login. The newer version (v4.0 for iOS and Android, v1.9 for Windows) signs you in to the map page automatically. This is convenient for most users while you might not want this function. You can stop this behavior in your account page. Look for the option "allow accessing online map from tracker app".