module 1 - part 1.pptx.pdf

GEOMATICS AND SURVEYING PRACTICES DEPARTMENT OF CIVIL ENGINEERING RAJAGIRI SCHOOL OF ENGINEERING AND TECHNOLOGY  SURVEYING Definition of surveying SURVEYING is the art of determining the relative positions of different features on, above or beneath the surf...

GEOMATICS AND SURVEYING PRACTICES DEPARTMENT OF CIVIL ENGINEERING RAJAGIRI SCHOOL OF ENGINEERING AND TECHNOLOGY  SURVEYING Definition of surveying SURVEYING is the art of determining the relative positions of different features on, above or beneath the surface of the earth by means of direct or indirect measurements of distance, direction and elevation and finally representing them as plans, maps or sections.  Objectives of surveying Objectives of surveying  Principles of surveying Principles of surveying Two basic principles of surveying are: 1. Always work from whole to the part 2. To fix or locate a new station by at least two measurements (linear or angular) from fixed reference points  Principles of surveying Always work from whole to the part: According to the first principle, the whole survey area is first enclosed by main stations (i.e. Control stations) and main survey lines. The purpose of this method of working is to control accumulation of errors. During measurement, if there is any error, then it will not affect the whole work, but if the reverse process is followed then the minor error in measurement will be magnified.  Principles of surveying According to the second principle the points are located by linear or angular measurement or by both in surveying. Let A & B are control points, a new point C can be established. Following are the methods of locating point C from reference points A & B. The distance AB can be measured accurately and the relative positions of the point can be then plotted on the sheet to some scale. (a) Taking linear measurement from A and B for C. (b) Taking linear measurement of perpendicular from D to C. (c) Taking one linear measurement from B and one angular measurement as