There is no way to do this via the dashboard at the moment, sorry! As you've stated, you can do it using the api.
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
There is no way to do this via the dashboard at the moment, sorry! As you've stated, you can do it using the api.