The document summarizes common units of measurement used in surveying for length, area, volume, weight, angles, temperature, and pressure. It provides conversion factors between British and metric units as well as between different units within each system of measurement. For example, it states that 1 foot is equal to 12 inches in the British system of length measurements and 1 meter is equal to 1000 millimeters in the metric system.

1. Unit Measurement
In surveying, the most commonly used units define quantities of length (or distance),
area, volume, weight and horizontal or vertical angles. The two systems used for
specifying units of measure are the British (English ) and metric systems.
1. Length
a. British Unit
The basis units for length or distance measurements in the British System are
inch, foot, yard and mile.
1 foot = 12 inches
1 yard = 3 feet
1 rod = 5.5 yards = 16.5 feet
1 chain = 4 rods = 66 feet = 100 links
1 furlong = 10 chain = 40 rods = 660 feet
1 mile = 8 furlong = 80 chain = 320 rods = 1760 yards = 5280 feet
b. Metric Units
The basic unit of length in the SI system is the meter. The subdivisions of the
meter are the millimeter, centimeter, and the decimeter, while multiples of meters
include the decameter, hectometer, and kilometer.
1 meter = 1000 millimeters
1 meter = 100 centimeters
1 meter = 10 decimeters
1 decameter = 10 meters
1 hectometer = 100 meters
1 kilometer = 1000 meters
2. Area
a. British Unit
1 square foot = 12 inches x 12 inches = 144 square inches
1 square yards = 3 feet x 3 feet = 9 square feet
1 square rod = 16.5 feet x 16.5 feet = 272 square feet
1 square chain = 66 feet x 66 feet = 4356 square feet
1 square furlong = 660 feet x 660 feet = 435600 square feet
1 acre =
1
10
square furlong = 10 square chains = 160 square
rods

2. 1 square mile = 1 section = 640 acres
1 township = 36 sections = 36 square miles.
b. Metric Units
1 square meter = 1,000 mm x 1,000 mm = 10,00,000 square millimeters
1 square meter = 100 cm x 100 cm = 10,000 square centimeters
1 hectare = 100 m x 100 m = 10,000 square meters
1 square kilometer = 1000 m x 1000 m = 10,00,000 square meters
1 square kilometer = 100 hectars
3. Volume
a. British Unit
1 cubic foot = 12 inches x 12 inches x 12 inches = 1728 cubic inches
1 cubic yard = 3 feet x 3 feet x 3 feet = 27 cubic feet
1 acre foot = 43560 square feet x 1 foot = 43560 cubic feet
b. Metric Units
1 cubic meter = 1000 mm x 1000 mm x 1000 mm = 1,00,00,00,000 cubic millimeters
1 cubic meter = 100 cm x 100 cm x 100 cm = 10,00,000 cubic centimeters
4. Weight
a. British Unit
1 ounce = 16 drams
1 pound = 16 ounces
1 hundredweight (short) = 100 pounds
1 hundredweight (long) = 112 pounds
1 ton (short) = 2,000 pounds
1 ton (long) = 2,240 pounds
b. Metric Units
1 gram = 1000 milligrams
1 gram = 100 centigrams
1 gram = 10 decigrams
1 kilogram = 10 hectogram
1 kilogram = 100 decagrams
1 kilogram = 1000 grams
1 quintal = 100 kilograms
1 metric ton = 1000 kilograms

3. 5. Angular Measurement
In geometry, any horizontal or vertical angle is measured in degrees. These angles may
be given in decimal degrees or degrees, minutes, and seconds.
1 degree = 60 minutes = 3600 seconds
eg.: 45.555 degree = 45º 33' 20"
OR,
45.55 x 60 minutes = 2733.3 minutes
45.555 x 60 x 60 seconds = 163998 seconds
The radian is another unit of measure for angles. By definition, a full circle has 2π
radians or 360 degrees.
2π radians = 360 degree
1 radians =
360
2𝜋
degree
=
180
𝜋
degree
= 57.2958 degree
And,
1 degree =
2𝜋
360
radian
=
𝜋
180
radian
= 0.01745 radian
6. Temperature:-
a. British Unit
The Fahrenheit scale, or degrees Fahrenheit (°F), is used in the United States
to measure temperature. On the Fahrenheit scale, the freezing point of water
is 32°F while the boiling point is 212°F at standard atmospheric pressure.

4. b. Metric Units
The Celsius scale, or degrees Celsius (°C), is used the metric system to
measure temperature. On the Celsius scale, the freezing point of water is 0°C
while the boiling point is 100°C at standard atmospheric pressure.
The Fahrenheit and Celsius scales converge at -40° (i.e. -40°F and -40°C are
the same temperature).
(212 -32)°F = (100 - 0) °C
180°F = 100°C
1 °F =
100
180
°C
=
5
9
°C
And,
1 °C =
180
100
°F
=
9
5
°F
For British to Metric conversions
°F =
9
5
x °C + 32
°C =
5
9
x (°F - 32)
7. Pressure:-
Atmospheric pressure is the force per unit area exerted against a surface by
the weight of the Earth’s atmosphere above that surface.
a. British Units
In this system, air pressure is typically measured in inches mercury (inHg).
1 atm = 29.2125 inHg

5. a. Metric Units
In this system, Air pressure is measured in millimeters mercury (mmHg) or
millibars (mbars) in the metric system, but may also be measured in pascals
or kilopascals.
1 atm = 101325 Pa.
1 atm = 1013.25 mbars
1 atm = 760 mmHg
For British to Metric conversions
1 inHg x
1000
39.37
= 25.40 mmHg
Unit Conversion
The conversion between different units of measurement for the same quantity
is called unit conversion. To make measurement easier one of the units can
be converted into another system of measurement.
A conversion factor is used to change the units of a measured quantity
without changing its value.
a. Conversion factor for length
Meter Feet Inches Yards
1 3.28 39.37 1.0936
0.3048 1 12 0.333
0.0254 0.0833 1 0.0278
0.9144 3 36 1
b. Conversion factor for Areas
Square
Meter
Square Feet
Square
Inches
Square
Yards
1 10.76 1550 1.196
0.0929 1 144 0.111
0.00065 0.0069 1 0.00077

6. R-A-P-D
Square
Feet
Square
Meter
1 Dam 21.39 1.99
1 Paisa 4 Dam 85.56 7.95
1Aana 4 Paisa 342.25 31.8
1 Ropani 16 Aana 5476 508.72
Bigha-Katha-Dhur
Square
Feet
Square
Meter
1 Dhur 182.25 16.93
1 Katha 20 Dhur 3645 338.63
1Bigha 20 Katha 72900 6772.63
c. Conversion factor for Volume
1 cub. meter = 35.3 cub.feet.
1 cub. feet = 0.0283 cub. meter
1 mana = 10 muthi
1 kuruwa = 2 mana
1 pathi = 8 mana
1 muri = 20 pathi
c. Conversion factor for Weight
1 pound = 0.4536 kilogram
1 kilogram = 2.2046 pounds
1 tola = 11.66 gram
1 lal = 0.1166 gram
Chain and Tape Corrections
……. to be continued