Which one is the CORRECT statement?
Length of Gunter’s chain is 66 ft.
Understanding Surveying Chain Lengths
Surveying chains are historical measuring instruments used in land surveying. Different types of chains were developed for specific purposes, and they vary in length and the number of links they contain. This question tests knowledge about the standard lengths of common surveying chains.
Types of Surveying Chains and Their Standard Lengths
Let's look at the standard lengths of the chains mentioned in the options:
- Engineering Chain: This chain is typically 100 feet long. It consists of 100 links, with each link measuring 1 foot. Engineering chains are often used in engineering surveys.
- Gunter’s Chain (also known as Surveyor’s Chain): Invented by Edmund Gunter in the 17th century, this chain is standardized at 66 feet. It contains 100 links, meaning each link is 0.66 feet (or 7.92 inches). The length of 66 feet is significant because it is equal to one chain (or 4 rods), and 10 square chains equal 1 acre.
- Revenue Chain: This chain is shorter, measuring 33 feet. It consists of 16 links. Revenue chains were historically used for measuring fields in cadastral surveys for revenue purposes.
Evaluating the Given Statements
Now let's examine each statement provided in the options based on the standard lengths:
-
Statement: Length of engineering chain is 33 ft.
Evaluation: Incorrect. The standard length of an engineering chain is 100 ft.
-
Statement: Length of engineering chain is 66 ft.
Evaluation: Incorrect. The standard length of an engineering chain is 100 ft.
-
Statement: Length of Gunter’s chain is 66 ft.
Evaluation: Correct. The standard length of a Gunter’s chain is indeed 66 ft.
-
Statement: Length of revenue chain is 16 ft.
Evaluation: Incorrect. The standard length of a revenue chain is 33 ft.
Summary of Chain Lengths
Here is a summary table for quick reference:
| Type of Chain | Standard Length | Number of Links | Length per Link |
|---|---|---|---|
| Engineering Chain | 100 ft | 100 | 1 ft |
| Gunter’s Chain | 66 ft | 100 | 0.66 ft (or 7.92 inches) |
| Revenue Chain | 33 ft | 16 | 2.0625 ft |
Based on the evaluation, only the statement regarding the length of Gunter’s chain is accurate.
Revision Table: Surveying Chains
| Chain Type | Length (\(\text{ft}\)) | Links |
|---|---|---|
| Engineering | 100 | 100 |
| Gunter’s | 66 | 100 |
| Revenue | 33 | 16 |
Additional Information on Surveying Measurement
Understanding the historical units and tools in surveying provides context for modern practices. While chains are less common now, replaced by tapes and electronic distance measurement (EDM) devices, their influence is still seen in land area units like the acre, which is historically linked to the Gunter's chain.
- A furlong is 10 chains (\(10 \times 66 \text{ ft} = 660 \text{ ft}\)).
- A mile is 8 furlongs (\(8 \times 660 \text{ ft} = 5280 \text{ ft}\)).
- An acre is 10 square chains (\(10 \times (66 \text{ ft})^2 = 43560 \text{ sq ft}\)).
- A chain (specifically Gunter's chain) is equal to 4 rods.
Knowing these standard lengths is crucial for questions related to basic surveying concepts and historical measurement systems.
Important Questions from Linear Measurement
The engineer's chain is typically:
Correction for pull or tension in a tape is given by
Cross-staff is used for:
The scale of a drawing is given as 1 : 20.
What is the representative fraction?
An Engineer measured the distance between two locations on a plan having a scale of 1 cm = 50 m as 600 m. Later, however, he found that he used a wrong scale of 1 cm = 30 m to measure the distance. The true distance between the locations is:
