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Faculty of Applied Engineering and Urban Planning. Civil Engineering Department. Surveying. First Semester 2010/2011. Introduction. Lecture 2. Content. Definitions of Surveying and Surveyor Figure of Earth Types of Surveying Units of Measurement Scale of Surveys. Definitions.
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Faculty of Applied Engineering and Urban Planning Civil Engineering Department Surveying First Semester 2010/2011 Introduction Lecture 2
Content • Definitions of Surveying and Surveyor • Figure of Earth • Types of Surveying • Units of Measurement • Scale of Surveys
Definitions • Surveying • Art and science of making and analyzing measurements made on, above or below the surface of the earth, and the processing of these measurements into some positional formsuch as maps and coordinates. It also includes the opposite establishment of positions on earth that previously located on a plan or a map.
Definitions • Surveyor • A professional person with the academic qualifications and technical expertise to practice the science of surveying.
Definitions • Surveyor can be enrolled within the following practices: • Determination of size and shape of any part of earth surface. • Positioning of objects in space. • Determination of boundaries. • Measurement of natural resources • Value Assessment • Estimation of Construction Costs • Production of Plans, maps and charts
Importance and uses of surveying • Locating and describing property boundaries for area measurement, dispute resolution between neighbors, etc. • The preparation of plans associated with the work of the civil engineering, architect, builder and town planner. • The making of maps and plans for military, geographical, geological, agricultural and other purposes.
Sine the earth surface is the reference of all surveying measurements so the figure and size of the earth is very necessary. • The first trial to measure the earth size was by the ancient Greeks by Eratosthenes as follow: • Distance between Aswan and Alexandria • = 5000 stadia (each stadia = 185.2 m.) • Tan α = s/h = 7.2 º ( α = β ) • 5000 stadia / L(earth perimeter) = β / 360 • L = 46300 km. = 2 π R • R = 7368.874 km. • This value is larger than the accurate satellite measured value by only 16% Sun Pole α h s Aswan well Alexandria R The figure of the earthand itsrelation to survey measurements R β
The earth surface is irregular and can not be represented by mathematical model. • The geoid is the mean see level which result if there is no topography above mean see level and also this surface is irregular . • If the earth has a uniform density and topographic variation does not exist the geoid will have the shape of ellipsoid. Reference of measurements
For (areas < 50 km²)The reference is a plane. • For (50 km² < areas < 500 km²) the reference is a sphere of radius (R = 6372.2 km.) • For (areas > 500 km²) The reference is Ellipsoid with the following properties : a : semi major axis b : semi minor axis=a(1-f)=a(1-e²)½ f (flattening) = ( a – b ) / a ( the value of f is between 0 “ sphere ” and 1 “ flat surface ”. e : eccentricity (e² = (a² - b²)/a² = 1-(b²/a²) =2f –f²) NP b a The reference for measurements depend on the area to be surveyed as follow : SP
Types of Surveying • Size of Surveying: • Geodetic Surveying • Plane Surveying • Positioning of objects in space. • Ground Surveying • Remote Surveying
Types of Surveying • Purpose of Surveying: • Land Surveying • Topographic Surveying • Hydrographic Surveying • Route Surveying • Construction Surveying • Mine Surveying
Units of Measurement • Length: • English System inch (in “), foot (ft ‘), Yard (yd) • Metric System cm, m, km • 1 foot = 12 inches • 1 yard = 3 ft • 1 mile = 5280 ft • 1 inch = 2.54 cm • 1 ft = 30.48 cm = 0.3048 m • Area: • English 1 acre = 43560 ft • Metric 1 donum = 1000 m2 • 1 hectare = 10000 m2 • 1 km2 = 1,000,000 m2
Units of Measurement • Angles: • Sexagesimal • circle is divided into 360°, each is divided into 60 min (΄), each is divided into 60 seconds (΄΄) • 213° 24΄ 47΄΄
Units of Measurement • Decimal or Centisimal • circle is divided into 400 equal grads (g), each grade is divided into 100 simal minutes (c), each is divided into 100 centisimal (cc) • 128g 60c 47cc
Units of Measurement • The Radian System • The radian is defined as: the central angle opposite to a circular arc whose length is equal to its radius. • The whole circle has an opposing angle 2π
Solving Problem Convert the angle 213° 24΄ 47΄΄ into Decimal and Radian systems. Solution:
Solving Problem Convert the angle 115g 2c 14cc into Sexagesimal system. Solution:
Scale of Surveys • Architectural Works, Building Works, Location Drawings: • 1/50, 1/100, 1/200 • Site Plans, civil engineering works: • 1/500, 1/1000, 1/1250, 1/2000, 1/2500 • Town surveys, highway surveys: • 1/1250, 1/2000, 1/2500, 1/5000, 1/10000, 1/20000, 1/50000 • Mapping: • 1/25000, 1/50000, 1/100000, 1/200000, 1/500000, 1/1000000
Problem • Ex1: A line with length of 100m was rotated by 10" about one of its ends, what is the distance moved by the another end ? • Ex2: what is the angle opposite to circular arc of length 24 mm, and radius of 50m?