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| title | chunk | source | category | tags | date_saved | instance |
|---|---|---|---|---|---|---|
| Level (optical instrument) | 2/2 | https://en.wikipedia.org/wiki/Level_(optical_instrument) | reference | science, encyclopedia | 2026-05-05T09:43:16.386089+00:00 | kb-cron |
An automatic level, self-levelling level, or builder's auto level includes an internal compensator mechanism (a swinging prism) that, when set close to level, automatically removes any remaining variation. This reduces the need to set the instrument base truly level, as with a dumpy level. Self-levelling instruments are the preferred instrument on building sites, construction, and during surveying due to ease of use and rapid setup time. The world's first automatic level was introduced on 8 March 1950. It was produced by the German company Zeiss-Opton in Oberkochen. Main components of an automatic level include a tribrach – a lower, fixed, triangular or circular element containing three sockets for adjusting screws (or wedge rings), attached to the tripod with a heart screw – and an alidade – a movable (rotatable) part. In automatic levels, the spirit level is most often replaced by a pendulum-based opto-mechanical device called a compensator.
=== Digital electronic level === A digital electronic level is also set level on a tripod and reads a bar-coded staff using electronic laser methods. The height of the staff where the level beam crosses the staff is shown on a digital display. This type of level removes interpolation of graduation by a person, thus removing a source of error and increasing accuracy. During night time, the dumpy level is used in conjunction with an auto cross laser for accurate scale readings.
=== Transit level === A transit level also has the ability to measure both the altitude and azimuth of a target object with respect to a reference in the horizontal plane. The instrument is rotated to sight the target, and the vertical and horizontal angles are read off calibrated scales
== In popular culture == In the first chapter of Thomas Hardy's 1887 novel The Woodlanders, the narrator states, "He knew every subtle incline of the ten miles of ground between Abbot's Cernel and Sherton—the market town to which he journeyed—as accurately as any surveyor could have learnt it by a Dumpy level." In the online game World of Warcraft, there is a quest in Wetlands given by Surveyor Thurdan to retrieve his lost dumpy level. He even comments on the name, saying, "I didn't name the bloody thing, alright? Go look it up!"
== See also == Glossary of levelling terms Rotary laser level, laser levels used in surveying and construction Line laser level, laser levels used in carpentry and home improvement Theodolite Total station Philadelphia rod Water level (device)
== References ==
== External links == Checking a level Wye level (Y level)