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**Introduction** To Chain Surveying

Ch**ain surveying** is the method of surveying in which only **linear measurements** are taken in fieldwork.

These **types are of surveys** main suitable for surveying small **areas of land**. It describes the boundaries of the **plot, area of land,** and other **distances and angles** on the field.

Chain surveying is one of the **simplest methods** of **land surveying**. It is the type of **surveying **in that just linear measurements are made, **no angular measurements **are taken.

**What Is Surveying?**

**Surveying **is a method of determining the **relative position of the **object above or below the ground level. With the **help of surveying**, we can find out the** area of land, **size of plot and topography** of the area**, etc.

The detailed **survey work** is essential before starting **any construction** work for example a bridge,** railway ,** canal, dam, road, and

**highway construction.**

The** nature** of the** ground surface** and **topography of an area** can be known by the u**se of different surveying methods.**

Before starting can **road construction work**, a survey of different **possible routes** of the roa**d is carried** out. The possible **obstruction** such as canal, **nature water crossing** and g**round-level data** is collected to compare and find a **best suitable ro**ute for** road construction.**

## Fundametal **Principles Of Surveying**

There are two basic principles of surveying,

- Work from whole of part
- Fix the position of new point by at least two indipendant methods.

### 1. **Always Work From Whole to the Part**

**According **to this principle, a **whole area of survey** is covered triangle with **survey lines** and locating **major survey stations.**

The area is **sub-divided into** numbers of** small triangles.** The major advantage of using this * principle* is that all the

**objects of the survey**are now classes to

**survey line**which increases the

**accuracy of work.**

The **major survey lines** are measured very precisely with **surveying instruments. **The others **side’s triangle** is also measured. The main **goal of this principle easy to reduce the area of work by dividing it into sub-parts** which increase the **accuracy of work.**

**During survey work**, if any error is found it **will not affect** the survey work of the **whole area. **Always located new survey stations by taking reference of two survey lines.

As per the second principle of surveying, the survey point is to be fixed with linear and angular measurement or the use of both methods.

In case there are 2 control points that are fixed first, then other points are can be fixed by leanier measurement. Let say

If two control points are established first, then a new station can be located by linear measurement. Let A & B are major control points, another new point C can be located

The following are the steps to be followed to a located a new point with help of A & B points.

- Measure distance A & B and Draw the poisition of these points on the plain papers.
- Measure distance from A & B to C.
- Take right angle measurement from D to C.
- Take horizontal measurement from B and 1angular measurement as angle ABC
- Take another 2 angular measurements at A & Bas angles angle CAB and angle ABC.
- Mesure one angle at B as angle ABC and one linear measurement from A asAC

**Read More: Theodolite | Transit Theodolite | Types of Theodolite | Theodolite Parts**

**What Is Chain Surveying?**

Chain surveying is the method of surveying in that horizontal measurement and angle area taken in fieldwork.

These types are of surveys main suitable for surveying small areas of land. It describes the boundaries of the plot, area of land, and other distances and angles on the field.

In chain surveying, measurements are noted in separate book which is called “filed book”. The data of the survey includes – angle measurement, distance measurement, survey station, and base details, etc.

These data in the filed book is used to draw the survey work on the paper by taking proper scale.

**Principles Of Chain Surveying**

The main **principle of surveying** is to divide the **area of a survey** into numbers of small survey areas by **using triangles.** Measure the length with tap and angle with a compass. The measurement is used to plot a survey drawing on paper.

Since **triangulation** forms the** principle of chain surveying, **the chain survey is similarly sometimes called **chain triangulation.**

If area to be surveyed is **triangular **and if the lengths and sequence of its** 3 sides** are recorded, the plan of the area can be **easily drawn.**

However, if the area has more than **three straight boundaries,** for instance as in figure (a) it is no longer enough to measures the lengths of the sides completely.

The** field measurements** must be so arranged that the area can be plotted by** laying down triangles.** Various arrangements should be prepared to satisfy this **condition** but only two are given here as shown in **figure (b) and (c)**.

**Types Of Equipment Used In Chain Surveying**

The several types of equipment used in chain surveying are as follows.

- Chain
- Arrows
- Pegs
- Ranging Rods
- Plumb Bob
- Hammer
- Cross Staff
- Offset

### 1. **Chain**

In **chain surveying **chains are the considerably essential equipment for the procedure of survey. Chains are utilized to measure **horizontal distances**. **Chains **are created of **straight links** of galvanized** mild steel wire** named links.

The ends of each link are bent into a **looped hand** connected using **three oval rings** which afford **flexibility **to the chain. The chain is formulated of mild steel. The **ends of the chain** are given** brass handles **for **dragging **the chain on the ground.

The outside of the handle is the **zero points** or the **endpoint **of the chain and the **length of the chain** is assessed from the **outside** of one handle to the outside of the **additional**. The** length of a link **is the distance between the centers of the two consecutive **intermediate rings.** The end links contain the handles.

### 2. **Arrows **

These are the **marking pens** made of steel wire and mainly, **10 arrows **are given with a chain survey. Length may differ from **25 mm to 50 mm **but indicated length as per the **IS-Code.**

The arrow is made sharp and another end is bent into a **loop or circle **for the facility of carrying. The usage arrows are injected into the ground after **every chain length **measured on the ground.

### 3. **Pegs **

Pegs are utilized to mark the** position station** or **terminal point** of a **survey line**. They are pushed in the ground with the support of the **wooden hammer **and **kept 40 mm** above the ground surface.

The dimension of pegs is mainly **150 mm** long and **30 mm **square at the top. Pegs are generally available of** wooden**.

### 4. **Ranging Rods **

Ranging rods are **2 m – 3 m high** rods of steel or well-seasoned wood utilized the ranging of point. They are **coated **in **alternate colors **of the band either white & black, white & red, or black, white, and red in series.

The band is of length **200 mm**, so that can be utilized for the rough measurement of smaller length **2 m ranging rod** being more popular. They are **octagonal **or circular in **cross-sections** of **30 mm **diameter and are almost invisible at a distance of** 200 m**.

They are given with the white or yellow flag 0f **30 – 50 sq. cm** area tied near its stop.

### 5. **Plumb Bob **

While **chaining **along the s**loping surface** of the **ground, a plumb bob** is required to transfer the points to the ground. It is similarly utilized for **accurate centering **of the **theodolite **compass, **plane table,** etc over a **station mark** and for assessing the vertically of **ranging **poles.

### 6. **Hammer **

**Hammer **is used to **driving the pegs** and wooden pegs into the earth. Because some **hard soil** surface hammer is must to **insert **the **pegs** into the soil

### 7. **Cross Staff **

This is the tool utilized for **setting out right angles** to a** chain line**. It includes either the** frame or box **with two pairs of **vertical slits **and is mounted on a **pole shoe **for fixing in the ground.

The three types of **cross staff**,

**Open cross-staff****French cross-staff****Adjustable cross-staff**

### 8. **Offset **

The **offset rod** is the same as that of the **ranging rod.** They are should with a pointed** iron shoe** at one end and given with a **notch **or a **hook **at the different for **pushing **or **pulling** the chain through **hedges or different obstructions.**

## Different Chains Used In Surveying

**Depending upon the length** of the chain, these are divide into the following types,

### 1. **Metric Chains **

**Metric chains** are the most commonly utilized chain in **India**. These types of chains come in various lengths such as **5 m, 10 m, 20 m, **and **30 m**. The most commonly utilized is a** 20 m chain**.

**Tallies **are given at every **2 m** of the chain for **quick reading. **Every link of this type of chain is** 0.2 m. **The total length of the **chain **is noted on the **brass handle** at the ends.

### 2. **Steel Band Or Band Chain **

These types of chains come up the steel small band strip of** the same width** of **12 mm**–**16 mm** and** 0.3 mm**–**0.6 mm** thickness. This chain is divided by **brass studs** at every **20 cm** or instead of brass studs, the band chain may have graduated carving as a **centimeter**.

For easy **usage **and **workability**, **band chains** are wound on **steel crosses** or **metal reels **from which they can be handily **unrolled**. This steel band is accessible in **20 m**–**30 m** length and the width of about **12mm-16mm**.

### 3. **Gunther’s Chain**

A** Gunter’s chain** is **66 feet** lengthy and contains **100 links**, each link **0.66 feet** lengthy (7.92 inches). It was originally obtained for comfort in land measurement since **10 square** chains are equal to **1 acre**, also while measuring **linear measuremen**t.

- 10 Gunter’s chain =
__201.17 meter__ - 80 Gunter’s chain =
__1609.36 meter__

**Read More: What Is Total Station | Components of Total Station | Advantages of Total Station **

### 4. **Engineer’s Chain**

Being **100 feet** long and contains **100 links,** each link being **1 foot**. At every **10 links **brass tags are clamped with **notches **specifying 10 links segments.

The usages of the** engineer’s chain** are mainly measured to Feet.

### 5. **Revenue Type of Chain **

The Revenue chain is **33 feet **lengthy and contains 10 **links **each link is **2 feet 0.75 inches** long, the chain in surveying is utilized for measuring fields in **cadastral survey.**

**Procedure Of Chain Surveying **

The procedure of chain surveying is as follows,

**1.Reconnaissance: **The** preliminary inspection** of the to be **surveyed **is named the reconnaissance. The **surveyor** evaluates the area to be surveyed, surveys, or prepares an **index drawing **or **key plan**. He should also evaluate the problems of plotting the** survey line **and **supplementary work.**

**2. Marking Station: **The survey fixed up the required **no. of stations **at the **spot **from where the** **maximum possible **station** can be plotted

**Some Operation:- **

- Fixing of ranging rod or poles.
- Driving pegs.
- Making a cross (X) if the surface is hard.
- Digging & fixing a stone.

**3.** **Choose a way for passing** the **mainline**. Which should be as horizontal and **clean **as feasible and should be **passed **almost through the **center** of work.

**4**. **The** **ranging rods** are fixed on the station.

**5. After** **fixing the stations,** a chain in could be initiated.

**6.** **Make** **ranging **where ever essential.

**8. Measure** the chain edge and offsets.

**9. Enter the observation** and measurement in the field book.

**Errors In Chain Surveying**

Errors in chaining may be classified as,

**Personal Errors****Compensating Errors****Cumulating Errors**

### 1. **Personal Errors **

The **personal errors** include **incorrect recording, **reading from the** incorrect end of the chain**, etc., which are personal errors. These errors are **serious **and **cannot be inspected easily**. Care should be taken to prevent such **kinds of errors**.

### 2. **Compensating Errors **

This type of error may be sometimes **positive and **sometimes **negative.** Thus they are **likely to get compensated **when a large number of readings are obtained. The magnitude of such errors can be assessed by the **theory of probability.** The following are the examples of the errors,

**Wrong marking**of the end of a chain.**A fractional part**of the chain may not be accurate though the**total length**is corrected.**Graduations**in the tape may not be**similar throughout.**- In the
**method of stepping**while assessing the**sloping ground, plumbing**may be crude.

### 3. **Cumulating Errors **

The **errors **that arise often in a **similar direction** are called **cumulative errors**. In each reading, the error may be small, but when a large number of **measurements **are given rise to they may be considered since the error is often on **one side**. Some examples of such errors are:

**Bad ranging****Bad straightening****Erroneous length**of chain**Temperature deviation****Variation in applied pull**Non-horizontality**A sag in the chain**, if discontinued for measuring horizontal distance on sloping ground.

**Advantages Of Chain Surveying**

The advantages of the chain surveying method are as follows,

- Chain survey is the
**easiest**and**commonest method**utilized in surveying exercises. - The
**equipment**utilized to conduct a chain survey is**simple to utilize**. - The equipment utilized in the chain survey can
**easily be replaced.**For instance, measuring rods can be replaced with**measuring tape**. - This method does not involve
**complicated mathematical computations.**This is a relief for those who are afraid of mathematics. - In a chain survey, a
**limited number of people**are required to perform the survey. Generally, the chain survey team has**three people Booker, leader, and follower.**

**Disadvantages Of Chains In Surveying**

Chain surveying has following disadvantages,

- A simple chain survey
**cannot be performed**in**built-up areas**and**huge areas**. - A simple chain survey is subject to
**various changes of errors**of accumulation which may cause by the difficulty of the chain. - The
**chain linkage may fail**to stretch up appropriately and result in**wrong data**. Similarly**clogging of the chain**may read to an error in reading. - It is
**time-consuming.** - It may not be performed in areas with
**steep slopes**or**waterlogged areas.**Chain survey is generally performed in**dry areas**with gentle slopes. - It becomes more difficult
**too wet.** - Chain survey becomes a more difficult method when there are
**raised points (obstacles)**in between areas to be surveyed.

**Line Types In Chain Surveying **

There are four lines for chain surveying,

- Base Lines
- Chain Line
- Tie (Subsidiary) Lines
- Check (Proof) Lines

### 1. **Base Lines **

In the **chain survey maps**, there is three chain line and one extra line is measured with high precision is called the **baselines.** The accuracy of survey work in the chain surveying method depends on how precisely the baseline is measured.

To increase the **accuracy of survey work**, the baseline is select such it is the** longest line among all **the other line and passing to a **major area** of the survey area. For **better results base line** must be lain on a** flat ground surface.**

**2. Chain Line (Major Survey) Lines **

The lines that join **main station**s are termed chain lines or **major survey lines**.

### 3. **Tie (Subsidiary) Lines **

**Tie lines** join** two fixed points** on the chain line. The benefit of tie-line appears while checking** surveying exactness **in locating interior details such as **buildings **and **ways**.

### 4. **Check (Proof) Lines **

It joins the **triangle apex** to some fixed points on any two **triangle sides**. It is utilized to evaluate the accuracy of the framework. The length of the check line measured on the ground surface shall be **consistent** with its **length on the plan.**

**Obstacles In Chain Surveying**

There are three obstacles in chain surveying,

- Obstacles To Ranging
- Obstacles To Chaining
- Obstacles To Both Ranging And Chaining

### 1. **Obstacles To Ranging **

This type of obstacle in which the ends are not **intervisible** is relatively common except in a** flat region. **These may be** two cases.**

- Both ends of the line may be
**visible**from the**middle points**on the line.

- Both ends of the line may
**not be visible**from the**middle points**on the line.

### 2. **Obstacles To Chaining**

The **obstacle to chaining** prevents chain measuring immediately between **two points **and rises to a **set of difficulties** in which distances are found by** indirect measurement.**

**Read More: What Is Surveying | 23 Types of Surveying Equipment **

### 3. **Obstacles To Both Ranging And Chaining **

The **obstacle to ranging and chaining** may be in the two cases,

- When it is likely to chain around the obstacle. For example,
**a pond,**etc. - When it is not likely to chain around the obstacle. For example,
**a river.**

**Offset In Chain Surveying **

The **offsets** are the** lateral measurement** from the surveying lines to fixed the position of various objects concerning the **survey lines.** The types of offset,

**Perpendicular Offsets****Oblique Offsets**

### 1. **Perpendicular Offsets **

When the **angle **of the offsets is **90° degrees**. It is named perpendicular offsets.

**Perpendicular offsets** are also categories two types,

- Pythagoras theorem
- Swing method

#### **Pythagoras Theorem **

**This method** is utilized to **draw perpendicular** offsets and it depends on the principle of the **Pythagoras theorem.**

**Swing Method **

This method is similarly utilized to **draw perpendicular offsets** in **chains** in surveying and another survey. It depends on the** principle **that the **shortest distance** of any two-point is nothing but the perpendicular distance.

### 2. **Oblique Offsets **

When the angle of offsets is any **different angle **but not be **90°.** It is named **oblique **offsets. **Oblique offsets** are extremely used in **chain surveying**.

## How to Record Survey Data In Field Book

The** chain survey **reading is taken with **tape and chain **measurements are **noted down** in a sep**arate book**, it is called a** Field Book.**

In the field, there are **two lines are drawn** by hand in the **half way of the page**. These two-line represent the **chain lines** on the field.

### 1. Single Line Book

**Single line books** are used for a bigger **larger area** for more **descriptive measurement** work. In such** field books,** the chain line starts lower side of page and respectively **works upward** direction.

**Read More: Contour Interval | Index Contour | What are Contour Lines **

### 2. Double Line Filed Book

The **double-line field book **shown below in the drawing is the most commonly used for performing **ordinary survey works**. The observed distance is along the chain which is entered between the **two lines **of the page.

## FAQs

### Chain Survey

The **chain survey** is the whole area of the survey the area is allotted into a **network of triangles** and the sides of the **several triangles** are measured quickly in the field with **chain or tape**.

### What is Chain Survey and its types?

The **chain survey** is the whole are survey is divied into a network of triangles and the sides of the several triangles are measured quickly in the field with chain or tape.**Types Of Chains Used In Surveying**

1. Metric chains

2. Steel band or Band chain

3. Gunter’s chain or surveyor’s chain

4. Engineer’s chain

5. Revenue chain

### What does Chain surveying require?

The several types of equipment** used in chain surveying** are as follows,

1. Chain

2. Arrows

3. Pegs

4. Ranging Rods

5. Plumb Bob

6. Hammer

7. Cross Staff

8.Offset

### What are the advantages of chain surveying?

The **advantages of the chain surveying** method are as follows,

1. Chain survey is the easiest and commonest method utilized in surveying exercises.

2. The equipment utilized to conduct a chain survey is simple to utilize.

3. The equipment utilized in the chain survey can easily be replaced.

4. This method does not involve complicated mathematical computations.

5. In a chain survey, a limited number of people are required to perform the survey.

### Types of Chains In Surveying

The following are different types of chains used in surveying,

1. Metric chains

2. Steel band or Band chain

3. Gunter’s chain or surveyor’s chain

4. Engineer’s chain

5. Revenue chain

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