The free version of Pattern Keeper allows you to view PDF cross-stitch charts. You can access all the charts from all the major vendors and even download PDF versions. This way, you can view your chart as one continuous pattern. You can also mark finished stitches and see where you parked your threads. It is possible to mark an entire 10 by 10 square, and the app will keep you motivated as you can track your progress. 

The app is in beta, and the developers are constantly improving it. This application was developed to help you and to make your cross-stitch experience better.