Theodolite is a multi-function viewfinder that combines a compass, two-axis inclinometer, rangefinder, GPS, map, nav calculator, and geo-overlay photo/movie camera into one indispensable app. Uses are endless, and the app is great for land measurements, outdoor sports, sightseeing, navigation, and finding your way around. Theodolite has pro features and is used extensively by surveyors, geologists, architects, engineers, competitive sportsmen, first responders, military personnel, and search and rescue workers every day.
Source: Theodolite Augmented Reality Viewfinder for iPhone and iPad