Note for Surveying-2 - S-2 By Pralay Bagde

Topics ( 7 )

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SURVEY-2 I. INTRODUCTION 1) Total Station: A Total Station is a modern surveying instrument that integrates an electronic theodolite with an electronic distance meter. A theodolite uses a movable telescope to measure angles in both the horizontal and vertical planes. 2) A total station or TST (total station theodolite): is an electronic/optical instrument integrated with an electronic distance measurement (EDM) used for surveying. Fig: Total Station 3) Uses: To read slope distances from the instrument to a particular point, and an onboard computer to collect data and perform advanced coordinate based calculations. 4) GPS: GPS use satellite data to calculate an accurate position on the earth. These calculations can relate to the user’s position to almost any map projection within millissecond. Fig: GPS 5) GIS: Geographical Information System (GIS) is a technology that Visualizes spatial information& has the Power to create maps with images shown

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Fig: GIS 6) USES: Specially used for a vast range of tasks involving geography. 7) Advantages: Provides ability to show lots of information on one map. 8) DORNE Arial Surveying: Aerial survey is a method of collecting geomatics or other imagery by using airplanes, helicopters…etc. Fig: DRONE Arial Survey Measurements on aerial images are provided by photogrammetric technologies and methods. B. Advantages of Advance surveying 1) Modern surveying instruments provide faster and more precise surveying than conventional instruments. 2) Fully automatic electronic measurement. 3) Digital display of staff reading and distance. 4) Data storage & Direct transfer in instrument possible. C. Need of Advanced Techniques used in Surveying: The planning and design of all civil engineering projects of any magnitude is constructed along the lines and points established by surveying and as these instruments integrated with an electronic distance measurement have a capability of capturing measurements accomplish all tasks much more efficiently. Thereby plotation of Map of any structure becomes easy as well as enhanced the skills & reducing lengthy work & completed within a short duration of time. Recent techniques in surveying using advanced instruments provide actual location of any structure with respect to all aspects. D. Objectives 1) To Plot Shraddha park College Campus, using various advanced techniques in surveying. 2) To understand the New techniques such as Total station, GIS, GPS, DGPS...etc. 3) To study the various plotation techniques in surveying. 4) To develop the map of shraddha park college campus using a total station, GPS, GIS, DRONE Arial Survey.

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Tacheometric surveying: Procedure, Method, Advantages. Tacheometric surveying is a method of angular surveying in which the horizontal distance from the instrument to the staff stations are determined from instrumental observations only. Thus the chaining operations are eliminated. Field Work can be completed very rapidly Tacheometry is mainly used for preparing the contour plans of areas. As chaining is avoided, as far as possible, this method of surveying is best suited in broken and hilly areas, areas covered with stretches of water, Swamps, etc. where chaining will become very slow, tedious and inaccurate. Even though this method is not very accurate owing to the above-mentioned advantages, it is employed in location surveys of lines of communications such as roads railways, reservoirs, etc. What is Tacheometer?     What is Tacheometer? Methods of Tachometric Survey: o 1. Stadia System of Tacheometry;  i. Fixed Hair Method:  ii. Movable Hair Method; o 2. Tangential System of Tacheometric Surveying: Procedure for Tacheometric Surveying: Errors and Precautions in Tacheometric Surveying: A tacheometer is similar to an ordinary transit theodolite fitted with stadia wires in addition to the central cross-hairs. As accuracy and speed are necessary, the telescope fitted with a tacheometer must fulfill additional requirements. Also, the vertical circle should be more refined. The telescope of the tacheometer is usually longer than that of the Ordinary theodolite and has a higher power of magnification.

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The object glass is of greater diameter, and the lens system is of better quality. The magnification power should not be less than 20-25. The effective aperture should not be less than 3.5-4.5 cm in diameter facilitating the obtaining of a bright image. The multiplying constant of the instrument (f/I) is generally kept as 100. Sometimes an additional pair of cross-hairs is provided such that the multiplying constant (f/I) is 50. This is used for close sights. As the top and bottom hairs are read, arrangements may be provided by rack-and-pinion for the movement of the eyepiece in the vertical plane. It should be possible to take direct readings up to an angle of 5 degrees on the vertical circle. A Sensitive spirit level should be fixed on the “What is Tacheometer? underarm.” An instrument fulfilling the above requirements is used in fixed hair method of stadia surveying. For use in the movable hair method of stadia surveying, the above tacheometer will have a different type of diaphragm. Generally, the fixed central cross-hair and the vertical hair are stretched in the diaphragm frame. The movable top and bottom cross-hairs are mounted on different slides which can be moved by a micrometer screw. The diaphragm and the slides carrying the stadia wires are located in different vertical planes to prevent wear and tear. Micrometer screws which operate the stadia hairs are provided with milled heads and drum scales. The drums are divided into 100 parts. Readings may be taken up to 0.001 of the pitch of the screws. This instrument is also called as a subtense theodolite. Methods of Tachometric Survey: Various methods of tacheometry survey are based on the principle that the horizontal distance between an instrument Station “A” and a staff station “B” depending on the angle subtended at point “A” by a known distance at point “B” and the vertical angle from point “B” to point “A” respectively. This principle is used in different methods in different ways. Mainly there are two methods of tachometry survey. (1)Stadia system, and (2) tangential system. 1. Stadia System of Tacheometry; In the stadia system, the horizontal distance to the staff Station from the instrument station and the elevation of the staff station concerning the line of sight of the instrument is obtained with only one observation from the instrument Station. In the stadia method, there are mainly two systems of surveying.