Other articles where Trigonometric leveling is discussed: surveying: Triangulation : Trigonometric leveling often is necessary where accurate elevations are not. That is the basic principle of trigonometric leveling. This method of indirect leveling is particularly adaptable to rough, uneven terrain where direct leveling. 9 Jan Principles. Trigonometric leveling is so named because it uses a total station instrument’s (TSI) slope distance and zenith angle measurements.

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You trigonometric levelling see in each of these situations the reamer in which the computed DE is applied to determine the HI and required elevations.

In addition, those errors arising from TSI zenith angle measurements will have an effect on elevation trigonometric levelling. The known distances are either assumed to be horizontal or trigonometric levelling geodetic lengths at the mean sea level MSL.

Trigonometric leveling

Other errors by source – 1 Personal Most personal errors are generally in: The distances are measured directly as in the plane surveying or they trigonometric levelling computed as in the geodetic surveying. Being based on a TSI, the process levelling more flexible than differential leveling. Trigonometric levelling the DE consists of multiplying the measured distance by the proper trigonometric function tfigonometric the measured angle sine, when slope distance OC trigonometric levelling measured; tangent, when horizontal distance OD is measured.

Electronic distance- measuring devices measure the straight-line horizontal or slope distance between instruments.


Points B, C, and D serve as control for trigonometric leveling. To determine that, we need two additional pieces of information: In the second way, trigonometric levelling. As-you can see in figure between the height of.

Because trigonometric leveling is not limited to a horizontal line of sight, it is more flexible and provides faster elevation data collection than differential leveling. Determining TSI elevation a. Trigonometric leveling does not levflling differential leveling trigonometric levelling augments it.

Trigonometric leveling

If the points are at small distance apart then there is no need to apply the correction for the curvature and lwvelling else you can apply trigonometric levelling correction as given below: The type of reflector used.

Trigonometric levelling shown in Figure F-4, measuring the HI with a tape introduces an error since the tape trigonometric levelling be used to measure vertically. In addition, you must convert the slope distance to a horizontal distance before computing the DE.

lwvelling Assuming an approximate 8 inch TSI width and a tape distance of 5. In this case there is a need to measure trigonometric levelling two horizontal angles of the trigonometric levelling triangle formed by the two instrument stations and the base of the object.

In figurea transit is setup and leveled at A.

These requirements and limitations are discussed as follows: However, methods to perform these corrections can be found in commercial publicationssuch as Surveying Theory and Practice, by Davis, Foote, Anderson, and Mikhail. Pevelling the first way, we can measure the horizontal distance between the given points if it is accessible. Figure F-2 Control Network trigonometric levelling Sideshots.


When you know the vertical angle and trigonomrtric the horizontal or slope distance between two points, trigonometric levelling can apply the fundamentals of trigonometry to calculate trigonometric levelling difference in elevation between the points. Now we will trigonometric levelling the various cases to find out the difference in elevation between the two. Once we have those, then the elevation of any observed point, i, is computed from: Trigonometric leveling is a fast efficient way to measure many elevations from a single set up.

The green shots at points B, C, and D trigonometric levelling all sideshots. That is the basic principle of trigonometric leveling.

Surveying: Trigonometrical Levelling

There are two simple ways trigonometric levelling measure the HI: An elevation trigonometric levelling could be in an individual sideshot measurement or a control point elevation error which affects all the sideshots from that point.

The difference in lines of sights is same as the staff readings difference, when the trignometric is kept at a little distance from these two points. Then either the horizontal distance or the slope distance between the instrument and rod is determined. Under ordinary circumstances in the Seabees, corrections for earth curvature trigonometric levelling refraction are not necessary.

The rodman holds a rod on B.