Angles are a fundamental part of measurement in 2-D and 3-D surveying. While modern total stations have almost completely replaced optical and electronic theodolites for most work, the need to measure angles has not changed. While total stations are designed to support measurement of large numbers of single observation measurements, such as are used for topographic surveying, there is still a need for precise and reliable angle measurements for control, setting-out, construction and other tasks.

This report discusses instrument construction and internal operations, because this is needed to understand why the recommended observation procedures are done as they are. Both optical and electronic reading systems are presented, so that the differences may be understood. As it happens, the same procedures that were developed for optical theodolites can be applied with only minor modifications to electronic theodolites and total stations. The nature of systematic errors in instruments are discussed, and the methods that are built into the observation procedures to eliminate them are presented.

$2.99