Chain Surveying

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Chain Surveying

Chain surveying is one of the oldest and most fundamental techniques used in land surveying. Dating back to ancient times, this method involves using a chain or measuring tape to measure distances and angles to create precise maps and plans of land. Despite the advancements in technology, chain surveying remains a valuable tool for surveyors, particularly in areas with challenging terrain or limited access. In this article, we will delve into the origins of chain surveying, its techniques, and its practical applications in modern-day surveying.

What is Chain Surveying

Chain surveying is a type of surveying in which measurements are made close to the ground using a chain or tape. This method is commonly used in surveying land for construction projects, road alignments, and property boundaries. The main equipment used in chain surveying includes a chain or tape for measuring distances, a compass or theodolite for determining angles, and pegs or stakes for marking points on the ground.

The process of chain surveying involves a series of steps. First, a baseline is selected and measured, which serves as the reference for all other measurements. The chain is then laid out along the desired path and distances are measured using the chain’s incremental markings. When obstacles such as trees or buildings are encountered, the chain is either bent or a new baseline is established. Angles are also measured at each point, either with a compass or theodolite, to accurately determine the direction of each line.

Chain surveying is considered to be a simple and cost-effective method as it does not require high-tech equipment or skilled technicians. However, the accuracy of the measurements heavily relies on the precision of the chain and the skill of the surveyor. In areas with complex terrain or dense vegetation, this method may not be suitable as it may be difficult to lay out the chain or obtain accurate measurements.

Despite its limitations, chain surveying is still a widely used method in civil engineering and land surveying. It provides a detailed and accurate map of the surveyed area, which is essential for planning and designing construction projects. It also allows for on-site adjustments and can be easily adapted for small or large-scale projects.

In conclusion, chain surveying is an important technique in the field of civil engineering. It plays a crucial role in accurately determining the boundaries, topography, and features of a particular area, which are essential in the design and construction of infrastructure projects. While it may have certain limitations, the simplicity and reliability of chain surveying make it a valuable tool in the surveyor’s arsenal.

Suitability of Chain Surveying

Chain surveying is a widely used method in the field of civil engineering. It is a traditional method of surveying which involves the use of a chain or tape to measure the distance between two points on the ground. This method is suitable for various types of land surveying projects and has been used for centuries due to its simplicity and accuracy.

One of the major advantages of chain surveying is its suitability for small and medium-sized land surveying projects. It is most commonly used for surveying agricultural land, road alignments, and small-scale topographic surveys. This method is particularly useful when working in areas with dense vegetation, rough terrain or obstacles such as rivers and lakes. It is also suitable for surveying areas with uneven ground as the chain can easily be laid out along the contours of the land.

Another advantage of chain surveying is its low cost. The equipment used for this method is simple and inexpensive, making it a cost-effective option for small projects. This makes it a popular choice for surveying projects that have a limited budget.

Furthermore, chain surveying does not require skilled personnel to operate the equipment, unlike other surveying methods such as Global Positioning System (GPS) or Total Station. This makes it a suitable option for projects in remote locations where there may be a lack of skilled surveyors.

Moreover, chain surveying is highly accurate when carried out correctly. With proper training and attention to detail, this method can produce accurate results with minimal errors. This makes it suitable for precision land surveys, especially in areas with limited infrastructure.

One of the limitations of chain surveying is its labor-intensive nature. As the equipment needs to be physically carried and laid out on the ground, it can be time-consuming and tiring. This can also result in human error if the surveyors are fatigued, leading to inaccurate measurements.

In conclusion, chain surveying is a simple yet effective method suitable for various types of land surveying projects. Its low cost, accuracy, and versatility make it a popular choice among civil engineers. However, it is important to consider the limitations of this method and ensure that it is appropriate for the specific project at hand.

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Un-suitability of Chain Surveying

Chain surveying, also known as the band/pacing method, is a traditional form of surveying that has been used for centuries. It involves the use of a chain and a set of poles to measure and map land boundaries and topographical features. While this method has been widely used in the past, there are certain limitations and drawbacks that make it unsuitable for modern engineering projects.

One of the major disadvantages of chain surveying is its lack of accuracy. The chain used for measurements can easily stretch or contract due to changes in temperature, humidity, and tension applied during the measurement process. This can result in errors in the measurements and ultimately affect the accuracy of the final results. The accuracy of chain surveying also depends on the skill and experience of the surveyor, as any small error in measurement can lead to significant discrepancies in the final map.

Another major drawback of chain surveying is its limited scope. The method is suitable only for small-scale surveys and cannot be applied to large or complex projects. The chaining process is time-consuming and requires the surveyor to walk along the entire length of the land, making it impractical for large-scale surveys. Moreover, it is not suitable for areas with dense vegetation, rough terrain, or water bodies. In such cases, alternative surveying methods like aerial surveys or GPS are more efficient and accurate.

One of the biggest challenges of chain surveying is its vulnerability to human error. A surveyor may miscount the number of turns or miss a stake, resulting in incorrect measurements. Moreover, chaining requires manual calculations, which can lead to computational errors and further inaccuracies in the final results. This method also heavily relies on the surveyor’s estimation and judgment, making it subjective and prone to mistakes.

In addition to these limitations, chain surveying also lacks efficiency and productivity. As the surveyor has to physically walk through the entire land, it is a time-consuming process. This can slow down the progress of the project and result in delays. The method also requires the use of multiple surveyors, poles, and chains, adding to the cost of the project.

In conclusion, while chain surveying played a crucial role in the history of land surveying, its unsuitability for modern engineering projects is evident. Its limited accuracy, scope, and efficiency make it an impractical and unreliable method for large-scale surveys. With the advent of advanced technologies like GPS and laser scanning, it is essential for civil engineers to embrace more precise and efficient surveying methods for successful project execution.

Instruments Used in Chain Surveying

Chain surveying is a commonly used method in civil engineering for determining the measurements and positions of points on a piece of land. It involves the use of a predetermined length of chain and specialized surveying instruments to measure distances and angles.

Here are some of the instruments that are commonly used in chain surveying:

1. Chains: As the name suggests, chains are an important tool in this type of surveying. They are typically made of steel and are used to measure linear distances on the ground. The most commonly used chain is the Gunter’s chain, which is 66 feet long and divided into 100 links.

2. Ranging rods: These are used to mark the positions of the end points of a chain and are placed perpendicular to the chain. They are usually made of wood or metal and help in achieving accurate and consistent measurements.

3. Arrows: Arrows are used to mark the points on the ground where the ranging rods are placed. They are typically made of metal and have pointed ends, making them easy to insert into the ground.

4. Measuring tape: In addition to chains, measuring tapes may also be used in chain surveying to determine smaller distances. They are more accurate than chains and are particularly useful for measuring short distances.

5. Compass: A compass is used to determine the direction of a line or an angle. It helps in maintaining a straight line while measuring distances using a chain.

6. Abney level: This is a simple, lightweight instrument that is used to measure vertical angles. It consists of a level and a sighting mechanism, making it useful for both leveling and measuring angles.

7. Theodolite: Theodolites are precision instruments used to measure horizontal and vertical angles. They consist of a telescope, a horizontal and vertical circle, and a spirit level, making them suitable for a variety of surveying tasks.

8. Plumb bob: A plumb bob is a tool used to establish a vertical reference line. It consists of a pointed weight attached to a string and is used to ensure the verticality of the ranging rods when marking control points.

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9. Clinometer: A clinometer is a device used to measure slopes and inclinations. It allows surveyors to determine the gradient of the land, which is crucial in planning construction projects.

10. Prism poles: Prism poles are used to mark points on the ground during surveying. They consist of a sturdy pole with a prism on top, which makes it easier to locate and measure points in the field.

In conclusion, chain surveying is a traditional method of surveying that relies on a combination of specialized instruments to measure distances and angles accurately. The above-mentioned instruments are essential for conducting a successful chain survey and play a significant role in determining the quality and accuracy of the survey results. As a civil engineer, it is important to be proficient in using these instruments to ensure the success of any chain surveying project.

Basic Terms Used in Chain Surveying

Chain surveying is a fundamental technique used in land surveying that involves measuring distances and creating detailed maps to determine the boundaries of a particular area of land. It is typically conducted with the use of a measuring chain, hence the name. To better understand this method, it is important to familiarize oneself with the basic terms used in chain surveying. Some of these terms include:

1. Station – A station is a fixed point on the ground from where the measurements are taken. It is marked on the ground and serves as a reference point for all subsequent measurements.

2. Base line – The base line is the longest line in a chain survey and serves as a reference for all other measurements. It is usually set along the longest dimension of the area being surveyed.

3. Tie line – A tie line is a line that connects two points on the ground. It is used to join and extend the base line to form a grid network for accurate measurements.

4. Chain – A chain is a measuring instrument used in chain surveying. It is typically made up of 100 links, each link being 7.92 inches in length.

5. Chainage – Chainage is the distance measured using the chain. It is measured in links, which are then converted to feet or meters for mapping purposes.

6. Offset – An offset is a perpendicular line drawn from a point on the base line to the object being measured. It is used to accurately measure the distance between the base line and the object.

7. Ranging – Ranging is the process of setting up the chain and marking a line on the ground connecting two points. It is done by aligning the chain along the points using one end as the station.

8. Obstacles – Obstacles refer to any natural or man-made features such as trees, rivers, buildings, etc., that may impede the chain surveying process. These are marked and avoided during the survey.

9. Theodolite – A theodolite is a precision instrument used to measure angles in chain surveying. It is mounted on a tripod and has a telescope for sighting the points being measured.

10. Traverse – A traverse is a series of connected lines joining the various points measured in a chain survey. It serves as the framework for mapping the area being surveyed.

Chain surveying is an essential tool for land surveyors in accurately mapping out the boundaries of a particular area. Understanding these basic terms will help in carrying out the survey efficiently and producing accurate results.

Types of Chain Used in Chain Surveying

Chain surveying is a traditional method of land surveying that involves the use of a chain to measure distances and outline boundaries. There are several types of chain used in chain surveying, each with its own unique characteristics and advantages. In this article, we will discuss the different types of chains used in chain surveying.

1. Gunter’s chain

Gunter’s chain was invented by English mathematician and surveyor Edmund Gunter in the 17th century. It is the most commonly used type of chain in chain surveying. The chain is made up of 100 links, with each link measuring exactly 7.92 inches. This makes the total length of the chain 66 feet which is equal to one chain. Gunter’s chain is made of iron or steel and is marked with brass tags at every 10 links for easy counting.

2. Engineer’s chain

Engineer’s chain is another commonly used type of chain in chain surveying. It is similar to Gunter’s chain in terms of length, but is made up of 100 links, with each link measuring 1 foot (12 inches). It is marked with brass tags at every 10 links like the Gunter’s chain, but also has additional tags at every half-link (6 inches). Engineer’s chain is commonly used for measuring smaller distances and is more accurate than Gunter’s chain.

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3. Metric chain

Metric chain is a modern type of chain that is used in countries that use the metric system of measurement. It is made up of 100 links, with each link measuring exactly 0.2 meters. This makes the total length of the chain 20 meters. The metric chain is marked with brass tags at every 10 links for easy counting.

4. Revenue chain

Revenue chain is a specialized type of chain used for measuring government land. It is made up of 80 links, with each link measuring exactly 15 inches. This makes the total length of the chain 40 feet. Revenue chain is marked with brass tags at every 8 links for easy counting.

5. Engineer’s tape

Engineer’s tape is also known as fiberglass tape or tape chain. It is made of a tough and durable fiberglass material and is typically used for measuring large distances. Engineer’s tape comes in different lengths, ranging from 50 feet to 300 feet. It is marked with a series of lines that indicate different measurements, making it easy to measure distances without the need for a chain.

In conclusion, the type of chain used in chain surveying depends on the purpose and accuracy required for the survey. While Gunter’s chain and engineer’s chain are commonly used for general land surveying, metrics chain and revenue chain are used for specific purposes. Engineer’s tape is a modern alternative to chains and is commonly used for measuring large distances. As a civil engineer, it is important to understand the different types of chain and their uses in order to conduct accurate and efficient chain surveys.

The procedure of Chain Surveying

Chain surveying is a fundamental technique used in civil engineering for determining the relative positions of points on the Earth’s surface. It involves the use of a chain or tape, along with other simple instruments, to measure distances and angles between points.

The following is the procedure of chain surveying:

1. Reconnaissance: This is the initial step in any surveying process. It involves a thorough study of the area to be surveyed, considering factors such as topography, accessibility, and any physical features that may affect the survey.

2. Marking the stations: The surveyor identifies and marks the primary stations (also known as stations) on the ground where measurements will be taken. These stations are usually marked with wooden pegs, steel pickets, or masonry pillars.

3. Setting up the tripod and sighting: A tripod is set up at each station, with the help of a plumb bob, to ensure that it is accurately vertical. The surveyor then uses a compass or a theodolite to establish the direction of the baseline. This is the reference line from which all other measurements will be taken.

4. Taking measurements: With the baseline established, the surveyor measures the distances between points by using a chain or tape. The chain is usually 100 feet long and is divided into 100 links, each measuring one foot. The length of the chain can vary depending on the accuracy required for the survey.

5. Calculating offsets: In addition to measuring the distances between points, the surveyor also takes offsets or measurements at right angles, from the baseline, to any features or objects that need to be included in the survey.

6. Recording data: The surveyor uses a field book to record all the measurements and offsets taken at each station. This data is crucial for drawing an accurate plan or map of the area being surveyed.

7. Closing the survey: Once all the measurements have been taken, the surveyor returns to the starting point and measures the last line back to the first station. This is known as the “closing line” and its accuracy is crucial in validating the survey.

8. Plotting: After completing the field work, the surveyor uses the recorded data to plot the points and draw a map or plan of the surveyed area. This map or plan is then used for future reference or as a basis for further engineering works.

In conclusion, chain surveying is an essential surveying method used in civil engineering, especially for smaller areas. With its simple and systematic procedure, it ensures accurate and reliable measurements, making it a crucial tool for various construction projects.

Conclusion

In conclusion, chain surveying is a fundamental technique used in many fields, such as civil engineering, land management, and mapping. It is a reliable and cost-effective method for gathering accurate data on the topography and boundaries of a specific area. While it may require physical labor and detailed planning, its results are highly precise and easy to interpret. With advancements in technology, chain surveying has evolved to include electronic and GPS equipment, making it even more efficient and accurate. However, it is important to follow proper procedures and techniques to ensure the reliability of the survey data. Overall, chain surveying continues to play a crucial role in accurately mapping and measuring the earth’s surface, and its uses are likely to expand as technology continues to advance.

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