If route is not defined, then check web.php routing file.
Route::get('/map', 'NavigationController@map')->name('map'); // note the name() method.
Then you can use this method in the views:
<a class="nav-link" href="{{ route('map') }}">{{ __('Map') }}</a>
PS: the __('Map') is to translate "Map" to the current language.
And the list of names for routes you can see with artisan command:
php artisan route:list