When geocaching, a GPS get you in the vicinity. Obviously you have to use your eyes to find the cache. Sometimes even that isn't easy, when you're talking about trick rocks, and logs. Different strokes for different folks. The elevation (altitude) derived by the GPS multiple triangulation is just as accurate as a barometric altimeter which can be affected by changes in the weather. I've used several barometric altimeters, and one thing a person learns is to check it before bedding down, and reset it in the morning, if the barometer has risen, or fallen during the night. The two main pieces of information a GPS gives you are your geographic coordinates, AND the elevation at your location. I didn't mention the altimeter function, or the coordinates function because that's just basic info.