The Dowsing Machine Poketch App can be obtained once you beat snowpoint City completely. After that, prof.rowan will come on a hover craft where they finaly destroy team galactic and they pick what app to get either the Dowsing Machine App or the water tracker app.
its not in the bag, its is located in the touchscreen part, where you can see the time, calculator just click the red button to scroll and go to downsing machine app, downsing machine is the one with large cross line.
How to get it:You get the dowsing maching app from Rowan's assistant on Route 207. How to use it:If you touch the touch screen and there is special stuff around, it will show you where. How to pick up items:You have to walk and stand in front of where it is and press the a button.