Yes it can, the app’s basic features needed for navigation can be used without an internet connection, as long as you download at least one of the available maps.
Since your map and the routing engine are both stored on your phone's storage, Karta GPS can easily calculate any route and guide you with turn-by-turn instructions, which may include road and street names.
To get a map select Downloads from the Main menu. You can then download and manage our free available maps at Free World Maps. To uninstall it tap the uninstall button .
Another useful feature which doesn't require internet connection, is the Safety Cameras information, that will alert you during navigation and on dashboard mode when you are approaching any speed cameras. To purchase this service, including regular updates of the speed cameras database, go to Downloads and check the Services section.