SURVEYING_chains-types
Explore the various types of surveying chains including the metric chain, Gunter’s chain, and revenue chain. Learn about their parts and applications in engineering and surveying.
10/12/20263 min read
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Surveying Chains: Essential Surveying Equipment in Civil Engineering
Introduction
Surveying chains are fundamental instruments used in land surveying to measure horizontal distances accurately. They have played an important role in civil engineering for centuries and are still useful in basic surveying practices, field demonstrations, and educational experiments. Surveying chains are commonly used for measuring land boundaries, preparing site plans, setting out building foundations, and carrying out chain surveying.
A surveying chain consists of a series of interconnected metal links, usually made of galvanized steel, connected by small rings. Handles are provided at both ends for convenient handling and measurement. The chain is laid along the survey line, and distances are measured by counting its full lengths.
Types of Surveying Chains
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The main types of surveying chains are:
1. Metric Chain
Metric chains are widely used in modern surveying. Common lengths are 5 m, 10 m, 20 m, and 30 m, with the 20 m and 30 m chains frequently used for fieldwork. A metric chain consists of links of 20 cm each. Therefore, a 20 m chain contains 100 links, while a 30 m chain contains 150 links.
2. Gunter’s Chain
Gunter’s chain is 66 feet long and
contains 100 links. It was
traditionally used in land
measurement and is particularly
associated with the acre-based
land measurement system.
3. Engineer’s Chain
An engineer’s chain is 100 feet long and consists of 100 links, each measuring one foot.
It was traditionally used in engineering surveys that employed imperial units.
4. Revenue Chain
A revenue chain is commonly associated with cadastral and land-record surveys. Its length and link arrangement depend on the local
land measurement system and surveying practice.
Parts of a Surveying Chain
The main components include:
Links: Metal segments connected to form the chain.
Connecting rings: Join the links and provide flexibility.
Handles: Allow surveyors to hold and stretch the chain.
Tallies or tags: Help identify chain lengths at regular intervals.
End rings: Connect the chain body to its handles.
Procedure for Using a Surveying Chain
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Select and mark the survey stations.
Clear obstacles along the survey line where necessary.
Align the chain between the stations using ranging rods.
Stretch the chain straight along the ground without unnecessary slack.
Place arrows or marking pins at the end of each chain length.
Count the complete chain lengths and measure the remaining distance.
Record the measurements in the field book.
The total distance is calculated as:
Total distance = (Number of complete chain lengths × Chain length) + Remaining distance
For example, if a 20 m chain is used for 5 complete lengths and the remaining distance is 8 m, the total distance is:
\[ D=(5\times20)+8=\boxed{108\text{ m}} \]
Advantages and Limitations
Surveying chains are economical, easy to operate, durable, and suitable for teaching basic surveying principles. However, their accuracy can be affected by sagging, incorrect alignment, temperature changes, worn links, and uneven terrain. Dense vegetation, steep slopes, and obstacles may also make chain surveying difficult.
Conclusion
Surveying chains remain valuable tools for understanding distance measurement and basic land surveying. For civil engineering students, learning the types, components, handling procedures, and limitations of surveying chains builds a strong foundation for practical fieldwork. Although modern instruments such as total stations, GNSS receivers, and electronic distance measurement devices are widely used today, chain surveying continues to provide essential hands-on knowledge.
