Traditional surveying techniques (introduction to civil engineering)

Ancient Egypt surveying
• Egypt is regarded as the home of the first
known Surveyors.
• Surveying was necessary in Ancient Egypt
because the annual floods buried or destroyed
boundary markers, which then had to be re-
established for ownership of the fields.
• Using only basic equipment the Pyramids
were built and aligned with astonishing
accuracy.

Surveying Tool: Plummet
A Plummet (aka Plumb Bob) is a small weight suspended
on a cord and is still much in use today.
The board was held vertically against the wall to be tested
and the Plumb Bob was attached to a wooden cross-
board so that the cord, if in a vertical position, would
touch a second cross board below, which was the same
size as the first.
Once a vertical is established then horizontals can also be
set by placing a Builders' Square against it. Plumb Bobs
were used also to establish a vertical Datum Reference in
other surveying instruments.

Surveying Tool: Square Level
A square level has two legs of equal length, connected at
a right angles and with a cross piece to create a tool in
the shape of the letter 'A'. From the connecting corner of
the two legs was suspended a Plumb Bob, which could
line up with a mark in the centre of the cross piece when
the two legs were stood on the horizontal surface of a
building stone for example.
The Square Level was the main levelling instrument used
not only in Ancient Egypt but also in later Roman and
Medieval building although water-filled trenches may
have been used to level larger distances

Surveying Tool: Groma
The Groma was a right-angle device designed for laying
out the corners of fields, much like the Surveyors' Cross
of more recent times.
The long vertical pole was set vertically in the ground at
the start corner and turned until one of the cross-pieces
lined up with one of the sides of the field to be set out.
Sightings were then made along the second cross piece
and a Ranging Pole, some distance from the Groma,
aligned and set into the ground to mark a line at right
angles to the first side.

Surveying Tool: Merkhet
One person would have stood at an observation
point and sighted the falling (or rising) star through a
narrow slit in a palm leaf, known as a Bay. A second
person could move until a Plum Bob suspended
from a Merkhet crossed the line of sight and then
mark a point on the ground. This process would be
repeated to create an angle between where a star
rises and where it falls. Bisecting this angle would
always give a true North.

Surveying Tool: 3-4-5 Triangle
Egyptians knew that a triangle with sides 3, 4 & 5 makes a 90 degree
angle.
As a matter of fact, they had a rope with 12 evenly spaced knots.
They used to build perfect corners in their buildings & pyramids.

Basic equipment to built Pyramids

Astonishing accuracy
The Great Pyramid at Giza (Khufu) has been measured at 231 meters square and the
largest discrepancy is 30cm between the north and west sides - but the difference
between the north and east sides is only 6cm!

Ancient Babylon (early Iraq) surveying
• A limestone tablet known as the
Babylonian Kudurru was inscribed
and set in the land.
• Develop base 60 system.
• This boundary stone, the earliest
known example of one, held the
description of the property, the
name of the surveyor and the
owner, and the ownership history.
This stone also contained lengthy
curses for anyone who would
deny the owner’s right to the land
or move the stone.

Ancient Greece & Rome surveying
• Mathematicians including Thales and
Pythagoras traveled to Egypt to study geometry,
returning to impart their knowledge on
mathematicians and surveyors in Greece.
• In Greece, legendary figures, including Aristotle,
Plato, and Archimedes made the city of
Alexandria a great center of science, surveying,
and related endeavors.
• They were crucial in the creation of the straight
angles and perfect lines that shaped those
amazing buildings and coliseums that still stand
today.

Surveying Tool: Chorobates
the Chorobates consisted of a beam of
wood 6 m in length held by 2
supporting legs and equipped with 2
plumb lines at each end. The legs were
joined to the beam by two diagonal
rods with carved notches. If the
notches corresponding to the plumb
lines matched on both sides, it showed
that the beam was level. On top of the
beam, a groove or channel was carved.
If the condition was too windy for the
plumb bobs to work effectively, the
surveyor could pour water into the
groove and measure the plane by
checking the water level.
• Used to measure horizontal planes
• Similar to modern spirit levels.

Surveying Tool: Diopra
Disk being of wood of 60 cm in diameter.
It works in either of two planes. When
mounted horizontally on a tripod by
means of a swiveling joint, it is used to
project straight lines, in either
direction or in both, for marking on the
ground, and if necessary to lay out
further lines at right angles to them by
means of right angled diameter lines
inscribed on the disk. A quarter of the
rim is also graduated in degrees, a
facility used (as far as we know) for
celestial observations but not for
terrestrial surveying.
• Used to measure angles
• Similar to modern theodolite.

Surveying Tool: Hodometer
At device, a metal ball from each milliarum (Roman shaft) through a carefully
crafted wheel assembly, fell through the pipe. The two-wheeled car had wheels
of 4 pes (4 foot approx. 1,185 m) and a circumference of 12.5 pes (approx. 3.7
m). The wheel made 400 turns and 1 milliarum.
• Used to measure Distances
• Similar to modern odometer.

Traditional surveying techniques (introduction to civil engineering)

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