Great App!

Offline maps (several types to choose from), ability to choose the ares you want to download so you dont use more memory than necessary, contour lines on maps, built in altimeter that responds very quickly, 3D. Everything you would want except the ability to plan a route that follows the actual trail, not a series straight lines connecting waypoints. Get Footpath app for that (only app I have found that will "snap" to trail during planning a route) and export the result to Maps 3D and you have the best of all worlds!

Hikercycler about Maps 3D PRO - Hike & Bike, v4.1.2