Vertical angle vertical angle measurement principle means that in the same vertical plane, a line of sight between the target direction of the horizontal angle α theodolite rentals, also known as the vertical angle or elevation angle; angle vertical angle is 0 ° ~ ± 90 °. The angle between the line of sight with the plumb line is called the zenith distance domestic theodolite, zenith distance z angular values ??ranging from 0 ° ~ 180 °. When the line of sight when the angle is called a vertical elevation above the horizon, the angle is positive; line of sight when the value is negative as the angle of depression below the horizontal, the angle, as shown in FIG. From this angle measuring instrument is also equipped with a theodolite must be able to be placed vertical dial - vertical dial, or called Vertical angle measuring instrument in the measurement of the horizontal angle must have two basic conditions: (1) to give a horizontal, and the center can be easily placed in the direction of the line of intersection of the vertical line of the same scale disc - horizontal circle; (2) there must be a distant goal can aim the telescope, and to be able to make full circle rotation in the horizontal plane and the vertical plane, so that the level of the telescope through different target A and B. The difference between the figure for the two directions of the horizontal angle β A and B readings: β = ba measuring horizontal and vertical angles of the instrument. By the British mechanic Sisson (Sisson) first developed in about 1730 theodolite, improved after molding, the official British geodesy. 1904 Qingdao theodolite, Germany began production of glass dial theodolite. With the development of electronic technology, the emergence of electronic theodolite 1960s. On this basis, the 1970s made electronic speed measuring instrument. Industrial theodolites | theodolites | Jinke instrumentation provided by Qingdao Branch of the Instrument Co., Ltd. Qingdao Branch of the Instrument Co., Ltd. (www.qdjk17.com) strong, credible, in Qingdao, Shandong analytical instruments industry has accumulated a large number of loyal customers. The company better work attitude and constantly improving innovative ideas will lead the Branch of the Instrument and you hand in hand into the brilliant, for a better future!