I'm using the getTrails method, and it works great with my iPhone app. I allow the user to tap the trail URL, and the associated web site within the app appears describing the trail. On the web site there is text stating "navigate on-trail with our free app" and a link to the App Store and Google Play store. My suggestion is: if the app is already installed onto the users device, have another button link that opens the app. The user could tap that button which would leave my app and open the Hiking Project app. Thanks!