2. SURVEYING
•Art of determining relative position of objects on
the earth surface or above or beneath the earth
surface.
•Relative positions are determined by taking
horizontal and vertical distances.
•Horizontal and vertical angles accurately using
surveying equipments.
•After taking measurements computations are
done and maps are prepared.
3. •Different methods and instruments are used
to facilitate the work of surveying.
•The measured distances and directions are
represented through a plan or map to
suitable scale.
4. OBJECTIVES OF SURVEYING
•Take measurements to determine relative position of
existing features on or near the ground.
•To layout or mark positions of proposed structure on
ground.
•Data obtained from surveying are used to prepare plan or
map showing ground features.
•Setting out of engineering work like buildings, roads,
railway tracks, bridges and dams involves surveying.
•To determine areas, volume and other related quantities.
5. • The primary object of any survey is the
preparation of plan or map.
• Plan – Projection of a ground and the features
6. PRINCIPLES OF SURVEYING
•Work from whole to part
•To fix position of new stations by atleast two
independent points of reference
7. According to this principle, it is always desirable
to carryout survey work from whole to part. This
means, when an area is to be surveyed, first a
system of control points is to be established
covering the whole area with very high precision.
Then minor details are located by less precise
methods.
1.Working from whole to part
The idea of working this way is to prevent the accumulation of errors and to control and
localize minor errors which, otherwise, would expand to greater magnitudes if the reverse
process is followed, thus making the work uncontrolled at the end.
8. 2. Location of new station from two reference points
•Let A and B are the reference points and C is a new
station
1. By measuring distance AC and BC
• Used in Chain surveying
9. 2. By dropping perpendicular CD from C
• Measure AD and CD
• Using set square find AC
• Called offsetting and used for locating details
10. 3. By measuring distance BC and < ABC
• C obtained by solution of triangles
• Used in traversing
11. 4. By measuring distance AC and < ABC
•Swing arc of radius AC from A and < from B
•Meeting point is C
•Used in traversing
13. • PRIMARY DIVISIONS:
1.PLANE SURVEYING:
a) Earths curvature is not considered
b) Only small area is considered
c) For areas less than 250sqKm
d) Line joining any two points is treated as a straight line and angles as plane angle.
e) Line joining any 3 points as plane triangle
f) Used for layout of canals,highways, railways, bridges etc
g) Conducted by state agencies
CLASSIFICATION OF SURVEYING
14. 2. GEODETIC SURVEYING: (Trigonometrical survey)
a) Covers large areas of land with greater accuracy.
b) Curvature of earth is taken into consideration.
c) For areas larger than 250sqKm
d) Line joining two points on the surface of earth is curved and forms arc of a
great circle and line connecting three points forms spherical triangle
e) Conducted by national survey of India
15. DIFFERENCE B/W PLANE AND GEODETIC SURVEYING
Plane Surveying Geodetic Surveying
Curvature of earth is ignored Curvature of earth is taken into consideration
For small areas <250 sq.km For areas >250 sq.km
Accuracy is less Accuracy is more
Direction of plumb lines at various points are
assumed to be parallel
Direction of plumb lines at various points are
different
Used for establishing less important points For establishing Precise points of reference
17. 1. HYDROGRAPHICAL SURVEY
•Conducted on or near water surfaces like lake, rivers, harbours etc
•Marine surveys are special type of hydrographical surveys
•Consist of locating shore lines, estimation of water flow and
determination of profiles beneath water surface
•Marine surveys are special type of hydrographical surveys
18. 2. Land surveys
•To determine boundaries and areas of land
•1. Topographic surveys- Topographic features Eg: Hills,
Valleys etc.
•2. City surveys-Within city limits for urban planning
•3. Engineering surveys- For design and planning of
structures, roads etc
•4.Cadastral surveys-Fix boundaries of private owners
19. 3. ASTRONOMICAL SURVEYS
•To determine latitudes , longitudes , azimuths
for various places on earth by observing
heavenly bodies
•Absolute location of points can be obtained
20. B. Based on objective of survey:
i) Geological survey: systematic investigation of the geology beneath
a given piece of ground for the purpose of creating a geological map or
model.
ii) Mine survey: involved in the accurate measurement and
recording of mine workings
iii) Military survey: establishing strategic points for offense and
defense
iv) Archeological survey: unearthing hidden places and monuments
v) Control Survey:Establish location of horizontal and vertical
positions of control points using geodetic surveying
