A theodolite is used to measure both horizontal and vertical angles. It is an important tool for individuals specializing in triangulation networks and geolocation work. Beyond the fields of surveying and engineering, theodolites are useful in creating floor layouts and working with concrete slabs. You may also need a theodolite for work on golf courses, swimming pools, landscaping, or road design. Theodolites can be used to measure elevations, but auto levels will do this more accurately over long distances.