2. Surveying
♣It is the art of determination of horizontal distances,
differences in elevation, directions, angles, locations, areas and
volumes on or near the surface of the earth.
♣ It involves the measurement and recording of the size and
shape (including the vertical shape) of an area on the earth's
surface.
3. The process of survey divided into two parts:
(a) Field work- taking measurements
(b)Office work- computing and drawing
4. Object of survey
♣The primary object of survey is the preparation of plan or
map.
♣The results of surveys when plotted and drawn on paper
constitute a plan.
♣The representation is called a map, if the scale is small. If
the scale is large, it is called a plan.
5. Primary division of surveying
Surveying may be divided into two general classes:
(a) Geodetic surveying
(b)Plane surveying
Geodetic surveying is also called trigonometrical surveying . In this survey, the
curvature of the earth is taken into account, since large distances and areas are
covered.
In plane survey, the earth's surface is considered as a plane. The curvature of
the earth is not taken into account, as the surveys extend only to small
areas.
6.
7. I. Classification based upon the nature of the field of
survey:
(a) Land Surveys.
(b) Marine or Navigation Surveys.
(c) Astronomical Surveys.
8. II. Classification upon the object of survey:
(i) Archaeological surveys.
(ii) Geological Surveys -for determining different strata in the
earth's crust.
(iii) Mine Surveys- for exploring mineral wealth such as gold,
coal, etc.
(iv) Military Surveys- for determining points of strategic
importance both offensive and defensive.
9. III. Classification based upon the methods employed
in survey:
(a) Triangulation Surveys. (b) Traverse Surveys
10. IV. Classification based upon the instrument
employed:
(i) Chain Surveys.
(ii) Theodolite Surveys.
(iii) Tacheometric Surveys.
(iv) Compass Surveys.
(v) Plane Table Surveys.
(vi) Photographic and Aerial Surveys.
11. Uses of survey:
The planning of all engineering and construction projects
extending over large areas, such as highways, railways,
irrigation, water supply etc., are based upon elaborate and
complete surveys.