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Feb 26, 2016 / Haseeb Jamal -

5 Travel Myths You Need to Stop Believing Right Now

Feb 26, 2016 / Haseeb Jamal -

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How to do Trigonometric Surveying

Geodetic or trigonometrically surveying takes into account the curvature of earth Since very extensive areas and very large distances are involved. In geodetic surveying highly refined instruments and methods are used. Geodetic work is undertaken by the state agency e.g. survey of Pakistan undertaken by the state agency. The object of geodetic surveying is to

What is Phototheodolite

A photo theodolite is a form of ground camera. It is a combination of camera and theodolite ans is used of taking photographic and measuring the angles which the rival plane of collimation makes with base line. The optical axis of the camera is arrange parallel to the line of collimation of the chocolate telescope and the theologize allows The determination of the orientation

What is Trilateration Surveying

Because of the development of highly accurate electronic measuring devices, a triangulation system can be completely observed, computed and adjusted by measuring the lengths o the sides in the network.

Applications of Triangulation

The establishment of accurately located control points for surveys of large. The accurate location of indirection work such as: Centre lines, terminal pts shafts for long tunnels

Classification of Triangulation System

Triangulation system may be classified according to Degree of accuracy required Magnitude of work

Types & Uses of Photographic Surveying

Photographic surveying also called photograph icing is a method of surveying in which plans or maps are prepared from photographic taken at suitable camera stations or photographic is the science of making measurement from photographs. In terrestrial photo-grammetry maps are prepared from terrestrial (or ground) photographs or terrestrial

Objectives and Uses of Hydrographic Surveying

It is the branch of surveying which deals with any body of still or running water such as a lake, harbor, stream or river. Hydrographic surveys are used to define shore line and under water features.

Method of Surveying a River & Sounding

The survey of the shore line of a river is made by running a theodolite and tape traverse on a shore at a convenient distance form the edge of the water. If the river is narrow, a single theodolite and tape traverse is on one bank and both banks. Located by staid or plane table methods. If the river is wide, it is necessary to run traverses on both banks and locate each shore

How to Establish controls in Hydrographic Surveying

In an extensive survey, the primary horizontal control is established primary horizontal control secondary once by running theodolite and tape traverse b/r the triangulation station, the traverse lines being run to following the shore lines approx. in survey of less extent the primer horizontal, control only is required and is established by running a theodolite and tape

Compound Curves in Engineering Survey

Combination of two or more simple circular curves of different radius having their curvature in the same direction. Essentially, a compound curve consists of two curves that are joined at a point of tangency and are located on the same side of a common tangent. Though their radii are in the same direction, they are of different values. tr= perception/reaction time

Errors and Corrections of Errors in Levelling

Collimation error occurs when the collimation axis is not truly horizontal when the instrument is level. The effect is illustrated in the sketch below, where the collimation axis is tilted with respect to the horizontal by an angle a:

Factors Affecting Construction of Tunnels

Tunnels are constructed To avoid the expensive acquisition of valuable built up land, tearing up pavements and holding up traffic for long periods in large cities. When the depth of ordinary cutting exceeds 20m and the ground rises rapidly for a considerable distance after wards. To avoid the excessive cost of maintenance of an open cut subjected to land slides or snow

Equipment and Advantages of Aerial Photography

Arial photogram try induces the use of photographs taken in a systematic manner from the air they are then controlled by lend survey and measured by photogrametric techniques. Since the First World War the terrestrial photographic surveying has been replaced by aerial photographic surveying or aerial surveying for most of survey work due to development of aero plane.

Types of and Uses of Photographic Surveying

Verticals are taken with the axis of the camera pointing vertically downward. These photographs can produce more accurate maps as the variation n scale over the area is smaller and no area remains hidden. However the details in photograph can not be easily identified as the view offered is unfamiliar to eyes. Oblique are produced by giving a camera a tilt up to 30 to the

Angle Measuring Equipment in Surveying

The theodolite is the basic instrument for measuring horizontal and vertical angles. It consists essentially of a sighting tube in form of a telescope, an horizontal and vertical scales, which are so set that horizontal and vertical angles of the object sighted in the telescope can be read from the scale (see fig. 5 and 6)

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