LEARNING NOTES
OPERATE
SURVEY
INSTRUMENTS
Kevin Kiprotich
, LAND SURVEYING LEVEL 6
LEARNING OUTCOME 1: OPERATE LINEAR MEASURING INSTRUMENTS
Learning Activities
1.1 Linear measuring instruments are identified as per survey procedures
1.2 Linear measuring instruments are operated as per manufacturer’s manual
1.3 Linear measuring instruments are maintained as per manufacturer’s instructions and
survey procedures
Linear measuring instruments are the surveying instruments for measuring distance between two
points in a straight line.
Units of linear measurements and their conversions
The units of measurement of distances have been recommended as metre for the execution of
surveys.
Surveyors use both metric and imperial unit systems. The common units of linear measurements are:
1. Metric Unit System
(i) Millimeter (mm)
1 mm = 0.001 meters (m)
- Used for fine measurements (e.g., construction details).
(ii) Centimeter (cm)
1 cm = 10 mm
1 cm = 0.01 m
- Often used in leveling or detailed plotting.
(iii)Meter (m)
1 m = 100 cm
1 m = 1000 mm
- This is the standard unit in surveying for general measurements like distances between
boundary points.
(iv) Kilometer (km)
1 km = 1000 m
- Used for large distances in geodetic surveys or road alignments.
2. Imperial Unit System
(i) Inch (in)
1 in = ft
1 in = 2.54 cm
- Sometimes used for small-scale detailed measurements.
(ii) Foot (ft)
1 ft = 12 in
1 ft = 0.3048 m
- The primary unit in many parts of the world, particularly in the U.S., for measuring land
distances.
PreparedbyKevinKiprotich
Page 1
, LAND SURVEYING LEVEL 6
(iii)Rod/Perch/Pole
1 rod = 16.5 ft
1 rod = 5.0292 m
- Used historically for land surveys and sometimes still referenced in legal descriptions.
(iv) Chain
1 chain = 66 ft
1 chain = 4 rods = 20.1168 m
- A commonly used unit in older land surveys (Gunter’s chain).
(v) Mile (mi)
1 mile = 5280 ft
1 mile = 80 chains
1 mile = 1.609 km
- Used for large distance measurements in land surveys, especially for highways and property
boundaries.
Note: Surveyors use these units based on the precision required and the geographic region they are
working in.
Methods of Linear measurements
There are two main methods of determining the distances between points on the surface of the earth:
(i) Direct method
(ii) Computative method.
(i) Direct Method.
In this method, distances are actually measured on the surface of the earth by means of chains, tape or
Steel bands.
(ii) Computative Method.
In this method, distances are determined by calculation as in tacheometry, trigonometry, triangulation
etc.
Note. Each method has its own limitation of the degree of accuracy (precision).
Types of linear measuring instruments and their operations
Linear measuring instruments are grouped into the following three categories:
A. Instruments for measuring distances.
B. Instruments for marking stations.
C. Instruments for setting out simple angles.
PreparedbyKevinKiprotich
Page 2
, LAND SURVEYING LEVEL 6
A. INSTRUMENTS FOR MEASURING DISTANCES
1. Measuring tapes
2. Surveyor’s chains
3. Steel Measuring bands
4. Electromagnetic Distance Measuring Instruments (EDMs)
5. Optical Distance Measuring Instruments (ODMs)
6. Sonic Distance Measuring Instruments (SDMs)
7. Tacheometers
8. Laser distance meters
Note: The first three instruments are used in direct linear measurements while the last five are
computative.
1. MEASURING TAPES.
Tape is a flexible ruler with graduated divisions in inches, meters, feet etc.
They are made in a variety of materials, length and weight depending on their use.
Types of Tapes.
Depending upon the material, tapes are classified as:
(i) Cloth or linen tape
(ii) Metallic tape
(iii) Steel tape
(iv) Invar tape
(i) Cloth or Linen Tape (Fig. 2.1)
Linen tapes are closely woven linen and varnished to resist moisture.
They are generally 10 metres to 30 metres in length and 12 mm to 15 mm in width.
One end of the tape is provided with a ring whose length is included in the total length of the tape.
Cloth tapes are little used in surveying but generally used for measuring subsidiary measurements
like offset measurements due to the following reasons:
(i) It is easily affected by moisture and thus gets shrunk.
(ii) Its length gets altered by stretching.
(iii) It is likely to twist and tangle.
(iv) It is not strong as a chain or steel tape.
PreparedbyKevinKiprotich
Page 3
OPERATE
SURVEY
INSTRUMENTS
Kevin Kiprotich
, LAND SURVEYING LEVEL 6
LEARNING OUTCOME 1: OPERATE LINEAR MEASURING INSTRUMENTS
Learning Activities
1.1 Linear measuring instruments are identified as per survey procedures
1.2 Linear measuring instruments are operated as per manufacturer’s manual
1.3 Linear measuring instruments are maintained as per manufacturer’s instructions and
survey procedures
Linear measuring instruments are the surveying instruments for measuring distance between two
points in a straight line.
Units of linear measurements and their conversions
The units of measurement of distances have been recommended as metre for the execution of
surveys.
Surveyors use both metric and imperial unit systems. The common units of linear measurements are:
1. Metric Unit System
(i) Millimeter (mm)
1 mm = 0.001 meters (m)
- Used for fine measurements (e.g., construction details).
(ii) Centimeter (cm)
1 cm = 10 mm
1 cm = 0.01 m
- Often used in leveling or detailed plotting.
(iii)Meter (m)
1 m = 100 cm
1 m = 1000 mm
- This is the standard unit in surveying for general measurements like distances between
boundary points.
(iv) Kilometer (km)
1 km = 1000 m
- Used for large distances in geodetic surveys or road alignments.
2. Imperial Unit System
(i) Inch (in)
1 in = ft
1 in = 2.54 cm
- Sometimes used for small-scale detailed measurements.
(ii) Foot (ft)
1 ft = 12 in
1 ft = 0.3048 m
- The primary unit in many parts of the world, particularly in the U.S., for measuring land
distances.
PreparedbyKevinKiprotich
Page 1
, LAND SURVEYING LEVEL 6
(iii)Rod/Perch/Pole
1 rod = 16.5 ft
1 rod = 5.0292 m
- Used historically for land surveys and sometimes still referenced in legal descriptions.
(iv) Chain
1 chain = 66 ft
1 chain = 4 rods = 20.1168 m
- A commonly used unit in older land surveys (Gunter’s chain).
(v) Mile (mi)
1 mile = 5280 ft
1 mile = 80 chains
1 mile = 1.609 km
- Used for large distance measurements in land surveys, especially for highways and property
boundaries.
Note: Surveyors use these units based on the precision required and the geographic region they are
working in.
Methods of Linear measurements
There are two main methods of determining the distances between points on the surface of the earth:
(i) Direct method
(ii) Computative method.
(i) Direct Method.
In this method, distances are actually measured on the surface of the earth by means of chains, tape or
Steel bands.
(ii) Computative Method.
In this method, distances are determined by calculation as in tacheometry, trigonometry, triangulation
etc.
Note. Each method has its own limitation of the degree of accuracy (precision).
Types of linear measuring instruments and their operations
Linear measuring instruments are grouped into the following three categories:
A. Instruments for measuring distances.
B. Instruments for marking stations.
C. Instruments for setting out simple angles.
PreparedbyKevinKiprotich
Page 2
, LAND SURVEYING LEVEL 6
A. INSTRUMENTS FOR MEASURING DISTANCES
1. Measuring tapes
2. Surveyor’s chains
3. Steel Measuring bands
4. Electromagnetic Distance Measuring Instruments (EDMs)
5. Optical Distance Measuring Instruments (ODMs)
6. Sonic Distance Measuring Instruments (SDMs)
7. Tacheometers
8. Laser distance meters
Note: The first three instruments are used in direct linear measurements while the last five are
computative.
1. MEASURING TAPES.
Tape is a flexible ruler with graduated divisions in inches, meters, feet etc.
They are made in a variety of materials, length and weight depending on their use.
Types of Tapes.
Depending upon the material, tapes are classified as:
(i) Cloth or linen tape
(ii) Metallic tape
(iii) Steel tape
(iv) Invar tape
(i) Cloth or Linen Tape (Fig. 2.1)
Linen tapes are closely woven linen and varnished to resist moisture.
They are generally 10 metres to 30 metres in length and 12 mm to 15 mm in width.
One end of the tape is provided with a ring whose length is included in the total length of the tape.
Cloth tapes are little used in surveying but generally used for measuring subsidiary measurements
like offset measurements due to the following reasons:
(i) It is easily affected by moisture and thus gets shrunk.
(ii) Its length gets altered by stretching.
(iii) It is likely to twist and tangle.
(iv) It is not strong as a chain or steel tape.
PreparedbyKevinKiprotich
Page 3
