Engineering Surveying
Unit 1 Introduction to Surveying
Definition
Surveying: “the art of making measurements of the relative
positions of natural and man-made features on the earth’s surface
and the presentation of this information either graphically or
numerically” (Bannister, Raymond and Baker, 1992)
Land surveying: the technique and science of accurately
determining the terrestrial or three-dimensional space position of
points and the distances and angles between them
Main types of Surveying
Plane surveying is a type of surveying which considers the earth’s surface to
be flat. It considers relatively small areas and therefore takes the earth’s
surface as a horizontal plane.
Geodetic surveying is a type of surveying which true shape (spheroid) of the
earth’s surface. It involves large areas of the earth’s surface and takes into
account the curvature of the earth.
Earth Shape:
Curvature
Branches of Surveying (Surveys classified according to purpose)
Control surveying: to establish horizontal and vertical positions of control
points to be used as reference points for other surveys.
Land surveying or Planimetric survey: to determine the boundaries and
areas of parcels of land; also known as property survey, boundary survey or
cadastral survey
Topographic survey: to prepare a plan/map of a region which includes
the natural, man-made and other features and their elevation
Engineering survey: to collect required data for planning, design
and execution of engineering projects
Construction survey: to establish points, lines, grades and for
staking out engineering works
Mine surveys: to carry out surveying specifically for mining
purposes
Plans and Maps
Plans and maps of a particular area are established from the survey data collected. The map
shows the location of a specific establishment such as buildings, vegetation, roads, etc. A plan
accurately defines the widths of roads, sizes of buildings and other features in large scale. Figure
1-1 shows an example of a map (a) and a plan (b).
Types of Maps
Maps are pictures or representations of the Earth’s surface. They show how places are related to each other by
distance, direction and size. Maps are a way of showing a part of the Earth’s surface on a flat piece of paper.
There are different types of maps varying according to their function or the type of information they show.
Four of the commonly-used types of maps include:
a. Physical map – shows the natural features of the earth like mountains, plateaus, plains, rivers, oceans, etc.
and are also known as relief map
Types of Maps
b. Thematic map – represent a variety of information including things like climate, precipitation, vegetation,
elevation, population, life expectancy, etc. Given figure shows a thematic map showing the population density of
Oman per square kilometers in 1990.
c. Political map – shows the political boundaries of cities, towns and villages, states, and
countries. Figure shows the political map showing the different municipalities of Oman.
Topographic Map: Figure include contour lines showing the shape and elevation of an
area. Lines that are close to each other indicate steep terrain while lines that are far apart
show flat terrain.
Types of Plans According to Purpose
Plans are produced to clearly illustrate the geometric features of a site or building. Its
presentation depends on its purpose. Plans can be categorized as follows:
ARCHITECTURAL PLAN: Example, site plan, floor plan, section drawing
STRUCTURAL PLAN: Example, column details, footing details, slab details
ARCHITECTURAL PLAN:
STRUCTURAL PLAN
Fundamental Concepts
Rounding OFF
RULE 1: If the highlighted digit is 1, 2, 3, 4 simply drop all digits to the right of rounding digit.
Example 1.1 ROUND OFF 3.423 to the nearest:
Hundredths
Tenths
Units
RULE 2: If the highlighted digit is 5, 6, 7, 8, 9 add one to the rounding digit and drop all digits to the right of rounding digit.
Exception to RULE 2: When the first digit dropped is 5 and there are no digits following or the digits following are zeros, make the
preceding digit even (i.e., round off to the nearest even digit).
Example 1.2
ROUND OFF 2.856 to the nearest:
Hundredths
Tenths
Units
Example 1.3
ROUND OFF 2.315 and 2.325 to the nearest hundredths
Units of measurement
Linear
Units of Measurement Commonly-used in Surveying
No. Item SI Unit English/US Units Conversion
Meter, m Feet, ft 1 m = 3.28 ft
Length/
1 Kilometer, km Yard, yd 1 in = 2.54 cm
Distance
Millimeter, mm Miles, mi 1 mi = 1.609 km
Square meters, m2 Square foot, ft2 1 acre = 4047 m2
2 Area
Hectares, ha Acre 1 ha = 10000 m2
Cubic meter, m3 Cubic foot, ft3 1 Li = 1000 cm3
3 Volume
Liters, Li Gallons, gal 1 gal = 4.546 Li
Kilogram, kg 1 kg = 2.205 lb
4 Pound, lb
Mass/weight Newton, N 1 kg = 9.81 N
Scaling
Methods of showing scale
Expressing in words
Drawn scale
Representative fraction
Large Scale and Small Scale Map
Large Scale and Small Scale Map
Obstacles to Measurement:
It sometimes happens that a survey line passes through some object such as a pond, a building, a river, a hedge
etc. which prevents the direct measurement of that part of the line which the object intersects. The interfering
object in such a case is called on obstacle.
It is necessary to overcome obstacles so that chaining may be continued in a straight line. The following
methods are, therefore, employed in measuring distances across the obstacles.
