S.H.H.S Building Construction
 Surveying or land surveying is the technique,
profession, and science of accurately determining the
terrestrial or three-dimensional position of points and
the distances and angles between them. These points
are usually on the surface of the Earth, and they are
often used to establish land maps and boundaries for
ownership or governmental purposes.
Number one (1) rule of Surveying:
Incorrect Data is worse then no data!
1. Decision Making – selecting method, equipment and
2.
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5.
desired final point locations.
Fieldwork & Data Collection – making measurements
and recording data in the field.
Computing & Data Processing – preparing calculations
based upon the recorded data to determine locations in
a useable form.
Mapping or Data Representation – plotting data to
produce a map, plat, or chart in the proper form.
Stakeout – locating and establishing monuments or
stakes in the proper locations in the field.
Plane Surveying – surveying with the reference base
for fieldwork and computations are assumed to be a
flat horizontal surface.
1.
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2.
Generally within a 12 mile radius the pull of gravity is very
nearly parallel to that at any other point within the radius
and thus horizontal lines can be considered straight.
Geodetic Surveying – surveying technique to
determine relative positions of widely spaced points,
lengths, and directions which require the
consideration of the size and shape of the earth.
(Takes the earth’s curvature into account.)
1.
2.
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4.
Photogrammetry – mapping utilizing data obtained by
camera or other sensors carried in airplanes or
satellites.
Boundary Surveying – establishing property corners,
boundaries, and areas of land parcels.
Control Surveying – establish a network of horizontal
and vertical monuments that serve as a reference
framework for other survey projects.
Engineering Surveying – providing points and
elevations for the building Civil Engineering projects.
Topographic Surveying – collecting data and preparing
maps showing the locations of natural man-made
features and elevations of points o the ground for
multiple uses.
Route Surveys – topographic and other surveys for
long – narrow projects associated with Civil
Engineering projects.
5.
6.

Highways, railroads, pipelines, and transmission lines.
Hydrographic Surveying – mapping of shorelines and
the bottom of bodies of water.
7.

Also known as bathymetric surveying.
 Datum - This is an arbitrary level surface to
which the heights of all points are referred. This
may be the National Datum or local datum
point established on a construction site.
Datum shifts can be very large. In one case, that of the Tokyo
Datum and the commonly used World Geodetic System 1984
(WGS84) the difference is measured in kilometers or miles.
 Mean sea level (MSL) is the average (mean) height of
the sea between High and Low tides
 Reduced Level (RL) – A distance recorded as a
Height Above or Below the DATUM. This height is in
feet.
RL 44.695
RL 27.969
In this case the DATUM is
Mean Sea Level
Mean
Sea Level
(MSL)
RL 21.146
RL 4.420
In this case the DATUM is lid
of Pit
Mean
Sea Level
(MSL)
 A benchmark (BM)in every-day language is a
point of reference for a measurement. In surveying
a benchmark is specifically any permanent marker
placed by a surveyor with a precisely known vertical
elevation (but not necessarily a precisely known
horizontal location). Designed to be used for many
projects.
A benchmark is physical
structure with a known or
assumed elevation.
To be considered a benchmark
the point should be identified
by a permanent or semipermanent structure that will
not be affected by frost heave,
traffic vibrations or
environmental changes.
Surveying standards have very
specific guidelines on the
required structure for
benchmarks.
RL 44.695
RL 27.969
In this case the DATUM is MSL
Benchmark is Top of Pit
Mean
Sea Level
(MSL)
 A Temporary benchmark (TBM) Benchmark
usually placed for a particular project. Not designed
to be a reference for other projects or for long term
use
RL 44.695
RL 27.969
In this case the DATUM is MSL
Benchmark is Top of Pit
Mean
Sea Level
(MSL)
 The historical method for
measuring distance is the
surveying chain.
 One of the first chains
used in the U.S. was the
Gunter’s chain.
 The Gunter’s chain was a
series of links attached to
a handle which included
an adjustment for wear.
 The chain was 22 yards
(66 ft) long.
Modern chains are metal strips 100 feet long.
Steel chain on holder
To rewind chain on holder:
1.
Hold holder vertical in the left
hand.
2.
Attach 100 foot end of the tape with
the numbers up.
3.
Wind tape up rotating the handle
clockwise.
4.
Remember to wipe tape with a dry
cloth as it is wound onto the
handle.
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Odometer Wheel
Odometer wheels use
different units on the
odometers.
Insure you know the
measuring units before you
start to use the wheel.
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Range finder
Range finders are used to measure
distance.
OPTICAL RANGE FINDER
Two primary types are optical and
EDM.
Optical range finders use lenses,
mirrors and principles trig to
determine distance.
EDM = Electronic distance
measuring
Many different models.
Many different features.
Many different prices. (Precision)
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The staff is simply a large ruler, available
in lengths of 3, 4 or 5 metres and
usually made of aluminium with
telescopic sections
Reading an E-type levelling staff
The value is ?
Read value at
the
horizontal
cross hair
1.930
1.920
1.910
1.900
•It is important to hold staff
plumb
•Use slow rocking technique
•Use vertical line in level to
keep plumb
Rocking the rod should be used when a rod level is
not available.
Set up the instrument where the benchmark can be viewed within correct
parameters and a reasonable number of sights can be viewed. This location
is identified as L1 circled in red
Definitions:
1- Backsight ( BS ): The first reading taken at every instrument station .
2- Foresight ( FS ): The last reading taken at every instrument station .
3- Intermediate sight ( IS ): Any reading taken at an instrument station between BS & FS
4- Turning point ( TP ): A point at which both BS & FS are taken before moving the staff
General Procedure:
The main purpose is to provide RL for a large number of points, such as the center line
of highway, or an area to produce a contour plan, this will be illustrated through the
following example of production longitudinal section (profile ) of a road.
A contour: is an imaginary line connecting points on the ground that have the
same elevation.
Contour Interval ( CI ): The vertical distance or elevation difference between two
successive contours.
Contour interval = 20m
1- Closely contours represent a steep slope, but spaced far contours represent a
flat slope.
2- Contours of different values do not cross each other except in a cave, nor do
they merge except in a vertically standing surface such as a wall.
3- A single contour can not split into two contours of the same value, and must
be a closed circuit not necessary in limits of the contour plan.
4- Irregular contours represent a rough and uneven terrain.
5- contours are perpendicular to the direction of the steepest slope.
6- A hill or depression are represented by closed lines.
Factors affecting choice of contour intervals:
1- Contour plan scale: The larger scale is the smaller contour interval.
2- The importance and purpose of a contour plan : for more details, a small
contour interval is used.
3- Accuracy, time and cost : For higher accuracy, a smaller interval is used.
4- The topography of the ground : For steep ground a large contour interval is
used, but for flat ground a small contour interval is used.
5- The area covered by the plan: For larger areas, a large contour interval is
used.