Vertical angle measuring principle is the angle between the vertical angle α detected in the same vertical plane theodolite, the horizontal line of sight between the direction of a target, 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 theodolite, zenith distance z angular values ??ranging from 0 ° ~ 180 °. When the line of sight at a vertical angle above the horizon called elevation theodolite metal, 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 Su light theodolite, and its center can be easily placed on the same line intersections with the direction vertical line of the scale disc - horizontal circle; (2) there must be a distant goal can aim the telescope, and To be able to make a 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 theodolite models, theodolite, 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!