Please open and read the full description. A simple parallel driving aid for the small farm, with AB-line, simple contour line and recording the already worn surface. The app is free for the liberated Ukraine. Attention: This is a demo, the demo has a running time limit and terminates after the expiration of itself. Please test the demo extensively before buying. If you have problems please use the external Bluetooth app to connect the GPS receiver: https://play. google.com/store/apps/details? id=googoo. android. btgpsUserforum for Android version from here: http://www.landtreff.de/post1119366. html#p1119366configure external GPS receiver: http://www.landtreff.de/post1291433. html#p1291433DIY receiver 1, uBlox N7M: http://www.landtreff.de/post1305701. html#p1305701DIY receiver 2, uBlox M8T: http://www.landtreff.de/post1371164. html#p1371164Ideas for external steering motor drive: http://www.landtreff.de/post1380443. html#p1380443first experiments with RTKlib: http://www.landtreff.de/post1397891. html#p1397891Please use the app only with external GPS receiver, e.g. this: http://www.landtreff.de/post1371550. html#p1371550https://www.google.de/search? q=Qstarz%20BT%20Q818XT%20GPS%20Receiverif there is not a option "Developer options / mock locations", then do the following: 1. go to the menu item "Settings / About phone"2. Click repeatedly on "Build number" until a message appears3. Now you have a new menu item "Settings / Developer Options"4. Here you can then "Allow mock locations" to enable (or also "Simulated locations") There are various options (press the menu button on the device to browse), a small guide can be found under "About.". For Tablet and Smartphone. Questions, comments, suggestions, please contact via email: email@example.comRecently integrated: Added simple partial widths view (beta) - Dutch added (thanks to Thomas) - French added (thanks to Francis) - Some bugs fixed (arrows, kml, ) - Text can be saved as a kml (press enter) - Worked route is saved as a kml file- Size of text and direction arrows can be adjusted- 3D display works now correct- App now runs as service in the background (home button) - Settings changed (press "? " for help) - Added simple contour line- Directional arrows to the line are shown in color- Current driving line is displayed in red- PayPal button added- Touch-and-zoom has been revised- Map will now always rotates forward- Northstar and GPS Simulation added- Areal recording revised (but still not perfect) - Direct integration of external Bluetooth GPS receiver- English added (google english) You need a different language? Then write me and help me.