SURVEYING - I

UNIT-1

PART-1

According to RTU syllabus

Syllabus of Unit-1

                                   Introduction:

• Importance of surveying to Engineers,
• Plane and geodetic surveying,
• Methods of location of points,
• Principle of surveying from whole to part,
• Conventional sign.

                        Measurement of Distances:

• Different types of chain,
• Tapes and their uses,
• Sources of Errors and precautions,
• Correction to tape measurements,
• Field problems in distance measurement     

Surveying Definition:

Surveying is an art of determining the relative positions of points on, above and below the surface of earth and presenting it graphically and numerically.

Importance of Surveying to Engineers:

• To determine relative position of points.
• To layout proposed structure on the ground.
• To measure relative quantities like area and volume.

Classification of Surveying:

Plane Surveying

Geodetic Surveying

• we neglect the effect of curvature of Earth's surface
• It is done for small area i.e.area less than 195.5 km^2
• It is done for local surveys.
• Plane trignometry is used.

• we consider the effect of curvature of Earth's surface.
• It is done for large area i.e. area greater than 195.5 km^2
• It is done to establish control points which serves the purpose of reference point for local survey.
• spherical trignometry is used

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Shape of Earth:

• oblate spheroid
• ellipsoid
• ovaloid
• new name given: GEOID

For Ease in calculation the shape of Earth is assumed to be spherical.

Great Circle:

• It is an imaginary circle passing through the center of Earth.
• A great circle divides the earth into two equal parts.

Spherical Triangle:

A spherical traingle is that triangle which is formed on the surface of a sphere by intersection of three arcs of great circle.

Spherical angle:

Spherical angle is defined as the angle between tangents to the great circle drawn at a point of intersection i..e. angle  A1 A A2.

 Properties of Spherical Triangle:

• Each angle of a spherical triangle should be less then 180°.
• Sum of spherical angles should be in range of 180°-540°.

Spherical Excess:

Amount by which the sum of the angles  of a spherical triangle exceed by 180 degree is called as spherical Excess.

ADITI SHARMA