LECTURE
NOTES : WHAT IS SURVEYING?
NOTES : WHAT IS SURVEYING?
☞
Surveying is the branch of applied
mathematics which deals with measuring
mathematics which deals with measuring
and recording of the size and shape
of any portion of the earth’s surface, and
of any portion of the earth’s surface, and
the delineation of the same in a map
or plan.
or plan.
☞
It deals with the setting out of
works such as roads, railways, waterworks,
works such as roads, railways, waterworks,
drainage schemes etc and the
calculation of areas and volumes.
calculation of areas and volumes.
☞
It may be taken to include levelling
i.e. determination of the relative heights
i.e. determination of the relative heights
of different points on the earth
surface.
surface.
TYPES
OF SURVEYING
OF SURVEYING
1. Trigonometrical surveying : –
This is for the preparation of maps of large
This is for the preparation of maps of large
extents of territory
2. Land surveying: – this is ranging
from the land division system and extensive
from the land division system and extensive
topographical surveys and work for
boundary commission to small ones such
boundary commission to small ones such
as farms and estates.
3. Hydrographical surveying: –
ranging from coast surveys to plans for harbour works.
ranging from coast surveys to plans for harbour works.
4. Engineering location surveying: –
For the construction of highways, railways
For the construction of highways, railways
and various public works.
5. Preliminary or parliamentary
surveys: – This is in connection with a projected
surveys: – This is in connection with a projected
scheme such as the construction of a
railway or a waterworks.
railway or a waterworks.
6. Exploratory surveying: – This is
for geological, engineering and mining
for geological, engineering and mining
enterprises including archaeological
expeditions.
expeditions.
7. Environmental survey: – his is
survey carried out for forest and water
survey carried out for forest and water
parameters.
DIFFERENCE
BETWEEN SURVEYING AND LEVELLING:
BETWEEN SURVEYING AND LEVELLING:
Surveying consists in making
measurements in the horizontal plane while
measurements in the horizontal plane while
Levelling is making measurements in
the vertical plane.
the vertical plane.
In surveying, the measurements
consist in fixing position of points in the
consist in fixing position of points in the
horizontal plane; 2 points fix a
straight line while 3 or more straight lines
straight line while 3 or more straight lines
determine the plan of a plane
figure.
figure.
WHAT
IS VISUAL SURVEY?
IS VISUAL SURVEY?
This is also called reconnaissance
survey.
survey.
⇒
It is the preliminary inspection of
an area to be surveyed.
an area to be surveyed.
⇒
It is a see-for-yourself walk-over
of the ground to be used for a fish pond or a
of the ground to be used for a fish pond or a
fish farm. It is first done with a
view to visualise the work to be done.
view to visualise the work to be done.
⇒
It is the venture taken to note and
identify all the parameters to be measured
identify all the parameters to be measured
or surveyed.
⇒
It is a rough sketch of the field or
fields in which all positions and stations
fields in which all positions and stations
are made in the field book.
⇒
It is preliminary work done whereby
the routes of the main chain lines are
the routes of the main chain lines are
noted.
WHAT
DO YOU DO DURING VISUAL SURVEY?
DO YOU DO DURING VISUAL SURVEY?
(i)
The purposes of the survey should be
noted.
noted.
This includes (a) is it for pond
construction?
construction?
(b) Is it for damming? (c) Is it for
irrigation purposes; (d) Is it for Hydro-electric power (HEP)? The purpose will
determine the extent of the reconnaissance survey.
irrigation purposes; (d) Is it for Hydro-electric power (HEP)? The purpose will
determine the extent of the reconnaissance survey.
(ii)
The water parameters to be measured
should be noted as from the beginning. Such parameters include : (a) Water
level; (b) Geological attributes;
should be noted as from the beginning. Such parameters include : (a) Water
level; (b) Geological attributes;
(c) Soil conditions (texture,
structure and permeability); (d) Water pH, hardness,
structure and permeability); (d) Water pH, hardness,
alkalinity, chloride, phosphate,
ammonia, sulphide, sulphite, dissolved oxygen
ammonia, sulphide, sulphite, dissolved oxygen
etc
SURVEY
IN POND CONSTRUCTION
IN POND CONSTRUCTION
Through topographic survey, the
proposed site is inspected and professionally
proposed site is inspected and professionally
approved. The water, soil and other
parameters are determined. Using levelling
parameters are determined. Using levelling
instrument, the topography of the
site is ascertained and the area to be dug/
site is ascertained and the area to be dug/
excavated or filled is pegged out
with the use of lines.
with the use of lines.
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