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Surveying Engg

CONTROL NETWORKS ( Linear survey )

The establishment of two- or three-dimensional control networks is the most fundamental operation in the surveying of an area of large or small extent. The concept can best be illustrated by considering the survey of a relatively small area of land as shown in Figure below:   prevent sag in …

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TERMS USED IN LEVELLING

Before studying the art of levelling, it is necessary to clearly understand the following TERMS USED IN LEVELLING :   1. Level Surface :  surface parallel to the mean spheroid of the earth is called a level surface and the line drawn on the level surface is known as a level line. …

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OBJECT AND USES OF LEVELLING

OBJECT AND USES OF LEVELLING As stated in the definition of levelling, the object is (i) to determine the elevations of given points with respect to a datum (ii) to establish the points of required height above or below the datum line. Uses of levelling are (i) to determine or …

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ADVANTAGES AND LIMITATIONS OF PLANE TABLE SURVEY

Advantages are: 1. Possibility of omitting measurement is eliminated. 2. The surveyor can compare the plotted work in the field then and there only. 3. Irregular objects are plotted more accurately, since they are seen while plotting. 4. Booking errors are eliminated. 5. Local attractions do not influence the plotting. …

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METHODS OF LINEAR MEASUREMENTS

Various methods used for METHODS OF LINEAR MEASUREMENTS may be grouped as: (i) Approximate (ii) Using chain or tape (iii) By optical means and (iv) Using electromagnetic distance measurement instruments. Approximates Methods of Linear Measurements……….. These methods are used in reconnaissance survey or to detect major mistakes committed while measuring with …

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Levelling staff

Levelling staffs are made of wood, metal or glass fibre and graduated in metres and decimals. The alternate metre lengths are in black and red on a white background. The majority of staffs are telescopic or socketed in three sections for easy carrying. Although the graduations can take various forms, the type adopted …

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Levelling

Levelling is the most widely used method of obtaining the elevations of ground points relative to a reference datum and is usually carried out as a separate procedure to those used in fixing planimetric position. The basic concept of levelling involves the measurement of vertical distance relative to a horizontal …

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HISTORY OF SURVEYING

HISTORY OF SURVEYING The earliest preserved writings on surveying are those of Heron the Elder; a Greek who lived in Alexandria about 150-100 B.C. His writings include a treatise, Dioptra (Surveyor’s Transit); a geometry book, Measurement; and an optical work, Mirrors. In Measurement, he describes the method used in determining the area of …

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CLASSIFICATION OF SURVEYING

Surveying is a very old profession and can be classified in many different ways. Classification Based on Accuracy of work. Two general classifications of surveys are geodetic. and plane. If! geodetic surveying the curvature of the earth is taken into account. Surveys are conducted with a high degree of accuracy. However in plane …

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