Prior to the theodolite, instruments such as the groma, geometric square and the dioptra, and various other graduated circles (see circumferentor) and semicircles (see graphometer) were used to obtain either vertical or horizontal angle measurements. Over time their functions were combined into a single instrument that could measure both angles simultaneously.
Theodolite Parts And Functions Pdf Freel
Railway engineers working in the 1830s in Britain commonly referred to a theodolite as a "Transit".[16] The 1840s was the start of a period of rapid railway building in many parts of the world which resulted in a high demand for theodolites wherever railways were being constructed.[17] It was also popular with American railroad engineers pushing west, and it replaced the railroad compass, sextant and octant. Theodolites were later adapted to a wider variety of mountings and uses. In the 1870s, an interesting waterborne version of the theodolite (using a pendulum device to counteract wave movement) was invented by Edward Samuel Ritchie.[18] It was used by the U.S. Navy to take the first precision surveys of American harbors on the Atlantic and Gulf coasts.[19]
Wild went on to develop the DK1, DKM1, DM2, DKM2, and DKM3 for Kern Aarau company. With continuing refinements, instruments steadily evolved into the modern theodolite used by surveyors today. By 1977 Wild, Kern and Hewlett-Packard were all offering "Total stations" which combined angular measurements, electronic distance measurement and microchip functions in a single unit.
The parts of a digital theodolite are mostly similar to a non-digital theodolite, except for the presence of a liquid crystal display (LCD), which shows the reading of the target in focus. The display system also has operating keys for changing the device settings.
It will have a base to support on a tripod stand. As per below, the figure shows a transit theodolite with its salient parts. Transit is the operation where the telescope can be reversed or revolved through 180Â in the direction of the vertical plane about its horizontal axis.
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