A free program for Android, by Topobyte.de.

Graz Offline City Map is an offline map app that can be downloaded to your phone and used without any internet connection. It allows you to view the city at high detail, browse the streets, find places of interest such as museums, restaurants, hotels, cafés, and many more. The app is designed to work offline and it does not require any internet connection for loading the maps or for searching the streets. As a result, you can use the app even if you do not have a data plan.

The app has been designed with the user in mind. It can be easily downloaded and used.