I want to verify the height of the ground which is provided to me with the help of an app if available. Of course, I am aware an app will not give me exact value but for me, it works if it shows relative height also.
OruxMap is one of the best android apps for navigation. You can get an approximate altimeter using device barometer Compass, you can use it for navigation, save your tracks, waypoints and POIs, and many more. It is free.