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The tribrach is attached to the tripod and placed over the marker. Looking through the optical plummet pick up two of the tripod legs and position the cross-hairs over the marker. Tread all three legs into the grass, bitumen, concrete. Look through the optical plummet and using the thumbscrews put the cross-hairs back over the marker.
The initial setting operation includes fixing the theodolite on a tripod, along with approximate levelling and centering over the station mark.For setting up the instrument, the tripod is placed over the station with its legs widely spread so that the centre of the tripod head lies above the station point and its head approximately level (by eye estimation).
A plumb bob, plumb bob level, or plummet, is a weight, usually with a pointed tip on the bottom, suspended from a string and used as a vertical direction as a reference line, or plumb-line. It is a precursor to the spirit level and used to establish a vertical datum. It is typically made of stone, wood, or lead, but can also be made of other ...
A theodolite (/ θ i ˈ ɒ d ə ˌ l aɪ t /) [1] is a precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes. The traditional use has been for land surveying , but it is also used extensively for building and infrastructure construction , and some specialized applications such ...
Used with survey and 3D point monitoring systems to measure changes in elevation and position of a point. A total station or total station theodolite is an electronic/optical instrument used for surveying and building construction .
A surveyor's tripod with a shoulder strap. The head of the tripod supports the instrument while the feet are spiked to anchor the tripod to the ground. A surveyor's tripod is a device used to support any one of a number of surveying instruments , such as theodolites , total stations , levels or transits.
Wild brand subtense bar. Another device used in tacheometry to measure distance between the measuring station and a desired point is the subtense bar. [2] This is a rigid rod, usually of a material insensitive to change in temperature such as invar, of fixed length (typically 2 metres (6.6 ft)).
The Möller–Trumbore ray-triangle intersection algorithm, named after its inventors Tomas Möller and Ben Trumbore, is a fast method for calculating the intersection of a ray and a triangle in three dimensions without needing precomputation of the plane equation of the plane containing the triangle. [1]