Ranging is the process of locating intermediate points along a survey line. There are two methods of ranging: direct ranging and reciprocal ranging. Direct ranging involves aligning intermediate points between stations that are intervisible, while reciprocal ranging is used when the stations are not intervisible and involves ranging from both ends simultaneously. Chain surveying involves dividing the survey area into a network of triangles and measuring the sides of the triangles directly in the field using chains or tapes, without taking angular measurements. The key principle of chain surveying is triangulation, where a plan can be drawn if the lengths and sequence of the three sides of a triangle are recorded.
Metric Chain : It Consists of galvanized mild steel wire of 4mm diameter known as link.
It is available in 20m, 30m, 50m length which consists of 100 links.
Gunter’s Chain : A 66 feet long chain consists of 100 links, each of 0.66 feet, it is known as Gunter’s chain.
This chain is suitable for taking length in miles.
Engineer’s Chain : A 100 feet long chain consisting of 100 links each of 1 feet is known as engineer’s chain.
This chain is used to measure length in feet and area in sq.yard.
Revenue Chain : it is 33 feet long chain consisting of 16 links.
This chain is used for distance measurements in feet & inches for smaller areas.
Introduction to surveying, ranging and chainingShital Navghare
This presentation contains the complete introduction of surveying. It also includes all the instrucments used in linear measurement and the terms related to Ranging and Chaining
This ppt presentation covers compass surveying, which explains principal of compass surveying, Types of compass, Difference between compass, Bearing, Definitions related to compass surveying etc.
Surveying is an important part of Civil engineering. Various part like theodolite, plane table surveying, computation of area and volume are useful for all university examination and other competitive examination
Metric Chain : It Consists of galvanized mild steel wire of 4mm diameter known as link.
It is available in 20m, 30m, 50m length which consists of 100 links.
Gunter’s Chain : A 66 feet long chain consists of 100 links, each of 0.66 feet, it is known as Gunter’s chain.
This chain is suitable for taking length in miles.
Engineer’s Chain : A 100 feet long chain consisting of 100 links each of 1 feet is known as engineer’s chain.
This chain is used to measure length in feet and area in sq.yard.
Revenue Chain : it is 33 feet long chain consisting of 16 links.
This chain is used for distance measurements in feet & inches for smaller areas.
Introduction to surveying, ranging and chainingShital Navghare
This presentation contains the complete introduction of surveying. It also includes all the instrucments used in linear measurement and the terms related to Ranging and Chaining
This ppt presentation covers compass surveying, which explains principal of compass surveying, Types of compass, Difference between compass, Bearing, Definitions related to compass surveying etc.
Surveying is an important part of Civil engineering. Various part like theodolite, plane table surveying, computation of area and volume are useful for all university examination and other competitive examination
Chain survey is the simplest method of surveying. ... The necessary requirements for field work are chain, tape, ranging rod, arrows and sometime cross staff. It is a system of surveying in which sides of various triangles are measured directly in the field and NO angular measurements are taken.
unit I
Introduction and Basic Concepts: Introduction, Objectives, classification and principles of
surveying, Scales, Shrinkage of Map, Conventional symbols and Code of Signals, Surveying
accessories, phases of surveying.
Measurement of Distances and Directions
Linear distances- Approximate methods, Direct Methods- Chains- Tapes, ranging, Tape corrections.
Prismatic Compass- Bearings, included angles, Local Attraction, Magnetic Declination and dip.
Chain survey is the simplest method of surveying. ... The necessary requirements for field work are chain, tape, ranging rod, arrows and sometime cross staff. It is a system of surveying in which sides of various triangles are measured directly in the field and NO angular measurements are taken.
unit I
Introduction and Basic Concepts: Introduction, Objectives, classification and principles of
surveying, Scales, Shrinkage of Map, Conventional symbols and Code of Signals, Surveying
accessories, phases of surveying.
Measurement of Distances and Directions
Linear distances- Approximate methods, Direct Methods- Chains- Tapes, ranging, Tape corrections.
Prismatic Compass- Bearings, included angles, Local Attraction, Magnetic Declination and dip.
Surveying and scale_Surveying, Civil EngineeringA Makwana
It is defined as the process of measuring horizontal distances, vertical distances and included angles to determine the location of points on, above or below the earth surfaces.
The term surveying is the representation of surface features in a horizontal plane.
The process of determining the relative heights in the vertical plane is referred as levelling.
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
Saudi Arabia stands as a titan in the global energy landscape, renowned for its abundant oil and gas resources. It's the largest exporter of petroleum and holds some of the world's most significant reserves. Let's delve into the top 10 oil and gas projects shaping Saudi Arabia's energy future in 2024.
TECHNICAL TRAINING MANUAL GENERAL FAMILIARIZATION COURSEDuvanRamosGarzon1
AIRCRAFT GENERAL
The Single Aisle is the most advanced family aircraft in service today, with fly-by-wire flight controls.
The A318, A319, A320 and A321 are twin-engine subsonic medium range aircraft.
The family offers a choice of engines
Hybrid optimization of pumped hydro system and solar- Engr. Abdul-Azeez.pdffxintegritypublishin
Advancements in technology unveil a myriad of electrical and electronic breakthroughs geared towards efficiently harnessing limited resources to meet human energy demands. The optimization of hybrid solar PV panels and pumped hydro energy supply systems plays a pivotal role in utilizing natural resources effectively. This initiative not only benefits humanity but also fosters environmental sustainability. The study investigated the design optimization of these hybrid systems, focusing on understanding solar radiation patterns, identifying geographical influences on solar radiation, formulating a mathematical model for system optimization, and determining the optimal configuration of PV panels and pumped hydro storage. Through a comparative analysis approach and eight weeks of data collection, the study addressed key research questions related to solar radiation patterns and optimal system design. The findings highlighted regions with heightened solar radiation levels, showcasing substantial potential for power generation and emphasizing the system's efficiency. Optimizing system design significantly boosted power generation, promoted renewable energy utilization, and enhanced energy storage capacity. The study underscored the benefits of optimizing hybrid solar PV panels and pumped hydro energy supply systems for sustainable energy usage. Optimizing the design of solar PV panels and pumped hydro energy supply systems as examined across diverse climatic conditions in a developing country, not only enhances power generation but also improves the integration of renewable energy sources and boosts energy storage capacities, particularly beneficial for less economically prosperous regions. Additionally, the study provides valuable insights for advancing energy research in economically viable areas. Recommendations included conducting site-specific assessments, utilizing advanced modeling tools, implementing regular maintenance protocols, and enhancing communication among system components.
Automobile Management System Project Report.pdfKamal Acharya
The proposed project is developed to manage the automobile in the automobile dealer company. The main module in this project is login, automobile management, customer management, sales, complaints and reports. The first module is the login. The automobile showroom owner should login to the project for usage. The username and password are verified and if it is correct, next form opens. If the username and password are not correct, it shows the error message.
When a customer search for a automobile, if the automobile is available, they will be taken to a page that shows the details of the automobile including automobile name, automobile ID, quantity, price etc. “Automobile Management System” is useful for maintaining automobiles, customers effectively and hence helps for establishing good relation between customer and automobile organization. It contains various customized modules for effectively maintaining automobiles and stock information accurately and safely.
When the automobile is sold to the customer, stock will be reduced automatically. When a new purchase is made, stock will be increased automatically. While selecting automobiles for sale, the proposed software will automatically check for total number of available stock of that particular item, if the total stock of that particular item is less than 5, software will notify the user to purchase the particular item.
Also when the user tries to sale items which are not in stock, the system will prompt the user that the stock is not enough. Customers of this system can search for a automobile; can purchase a automobile easily by selecting fast. On the other hand the stock of automobiles can be maintained perfectly by the automobile shop manager overcoming the drawbacks of existing system.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Welcome to WIPAC Monthly the magazine brought to you by the LinkedIn Group Water Industry Process Automation & Control.
In this month's edition, along with this month's industry news to celebrate the 13 years since the group was created we have articles including
A case study of the used of Advanced Process Control at the Wastewater Treatment works at Lleida in Spain
A look back on an article on smart wastewater networks in order to see how the industry has measured up in the interim around the adoption of Digital Transformation in the Water Industry.
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptxR&R Consult
CFD analysis is incredibly effective at solving mysteries and improving the performance of complex systems!
Here's a great example: At a large natural gas-fired power plant, where they use waste heat to generate steam and energy, they were puzzled that their boiler wasn't producing as much steam as expected.
R&R and Tetra Engineering Group Inc. were asked to solve the issue with reduced steam production.
An inspection had shown that a significant amount of hot flue gas was bypassing the boiler tubes, where the heat was supposed to be transferred.
R&R Consult conducted a CFD analysis, which revealed that 6.3% of the flue gas was bypassing the boiler tubes without transferring heat. The analysis also showed that the flue gas was instead being directed along the sides of the boiler and between the modules that were supposed to capture the heat. This was the cause of the reduced performance.
Based on our results, Tetra Engineering installed covering plates to reduce the bypass flow. This improved the boiler's performance and increased electricity production.
It is always satisfying when we can help solve complex challenges like this. Do your systems also need a check-up or optimization? Give us a call!
Work done in cooperation with James Malloy and David Moelling from Tetra Engineering.
More examples of our work https://www.r-r-consult.dk/en/cases-en/
CFD Simulation of By-pass Flow in a HRSG module by R&R Consult.pptx
Linear measurement
1.
2. Ranging
• When a survey line is longer than a chain
length, it is necessary to align intermediate
points on chain line so that the measurements
are along the line. The process of locating
intermediate points on survey line is known
as ranging. There are two methods of ranging
viz., direct ranging and reciprocal ranging.
4. Direct Ranging
• If the first and last points are intervisible this method is
possible.
• Stations A and B in which an intermediate point C is to
be located. Point C is selected at a distance slightly less
than a chain length. At points A and B ranging rods are
fixed. The assistant holds another ranging rod near C.
Surveyor positions himself approximately 2 m behind
station A and looking along line AB directs the assistant
to move at right angles to the line AB till he aligns the
ranging rod along AB. Then surveyor instructs the
assistant to mark that point and stretch the chain along
AC.
13. Indirect or Reciprocal Levelling
• Due to intervening ground, if the ranging rod at B is not
visible from station A, reciprocal ranging may be
resorted. Figure shows this scheme of ranging.
• It needs two assistants one at point M and another at
point N, where from those points both station A and
station B are visible. It needs one surveyor at A and
another at B. To start with M and N are approximately
selected, say M1 and N1. Then surveyor near end A
ranges person near M to position M2 such that AM2N1
are in a line. Then surveyor at B directs person at N, to
move to N2 such that BN2M2 are in a line. The process
is repeated till AMNB are in a line.
20. Linear Measurements
• The determination of the distance between two
points on the surface of the earth is one of the
basic operation of surveying. Measurement of
horizontal distances or measuring linear
measurement is required in chain surveying,
traverse surveying and other types of
surveying.
22. Linear Measurements
• In the direct method, the distance is actually
measured during field work using a chain or a
tape. This is the most commonly used method
for linear measurements.
• In the optical methods, principles of optics are
used. The distance is not actually measured in
field but it is computed indirectly. The
instrument used for making observations is
called tacheometer.
24. Linear Measurements
• Electronic Distance Measuring (E.D.M)
instruments have been developed quite
recently.
• These are practically replacing the
measurement of distances using chains or
tapes. There is a large variety of such
instruments and depending upon the precision
required the instruments should be used.
26. Linear Measurements
Approximate methods
• The methods given below may be used in
reconnaissance or for detecting major mistakes in
linear measurements obtained with a chain or a
tape.
Pacing
• A distance between two points can be
approximately be determined by counting the
number of paces and multiplying it with average
length of the pace.
29. Linear Measurements
Passometer:
• It is a small instrument which counts the
number of paces.
Pedometer:
• This instrument directly gives the distance by
multiplying the number of paces with the
average pace length of the person carrying the
instrument.
33. Linear Measurements
Odometer
• An odometer is a simple device which can be
attached to the wheel of a bicycle or any such
vehicle. The odometer registers the number of
revolution made by the wheel. The distance
covered is equal to the product of the number
of revolutions and the perimeter of the wheel.
35. Linear Measurements
Speedometer
• This is used in automobiles for measuring
distances.
Measuring Wheel
• It is a wheel fitted with a fork and handle. The
wheel is graduated and shows a distance per
revolution. There is a dial which records the
number of revolution. Thus the distance can be
computed.
39. Instruments Used in Chaining
• The following instruments are used while
chaining.
• Chains
• Tapes
• Arrows
• Ranging rods and offset rods
• Laths & Whites
• Pegs
• Plumb bob
• Line Ranger
40. Instruments Used in Chaining
Chains
• Various types of chains used in surveying are
• Metric Chain
• Gunter’s Chain or Surveyor’s Chain
• Engineer’s Chain
• Revenue Chain
• Steel Band or band chain
41. Instruments Used in Chaining
Metric Chain
• Normally this chain consists of galvanized
mild steel wire of 4 mm diameter known
as link. The ends of the links are bent into
loop and connected together by means of
three oval rings which provide the
flexibility to the chain and make it less
liable to kinking. Both ends of the chain
have brass handle with swivel joint so that
the chain can be turned round without
42. Metric Chain
• In a metric chain at every one meter interval of
chain, a small brass ring is provided. Brass tallies
are also provided at every 5.0 m length of chain.
Each tally has different shape which indicates 5 ,
10, 15m from any one side of the chain, metric
chains are available in 20 m and 30 m length.
• A 20 m chain has 100 links each of 20 cm and 30
m chain has 150 links. Length of chain is
embossed on the brass handles of the chain.
44. Instruments Used in Chaining
Günter's chain
• A 66 feet long chain consists of 100 links each
of 0.66 ft it is known as Gunter’s Chain
• Here, 10 sq chain are equal to 1 acre,
• 10 chains= 1 furlong and 8 furlongs = 1 mile
• This chain is suitable for taking length in miles
and areas in acres.
47. Instruments Used in Chaining
Engineer’s Chain
• A 100 ft chain of 100 links each of 1 foot is
known as Engineer’s chain. Brass tags are
fastened at every 10 links. This chain is used to
measure length in feet and area in square
yards.
50. Instruments Used in Chaining
Revenue Chain
• Revenue chain is 33 ft long chain consisting of
16 links. This chain is used for distance
measurements in feet & inches for small areas.
52. Instruments Used in Chaining
Steel Band or Band Chain
• Steel bands are preferred than chains because
they are more accurate, but the disadvantages
is that they get broken easily and are difficult
to repair in the field. They are 20 and 30 m
long, 12 to 16 mm wide and 0.3 to 0.6 mm
thick. They are numbered at every metre and
divided by brass studs at every 20 cm
55. Testing and Adjustment of Chain
• During continuous use, the length of a chain
gets altered. Its length is shortened chiefly due
to the bending of links. Its length is elongated
either due to stretching of the links and joints
and opening out of the small rings. For
accurate work it is necessary to test the chain
time to time. The chain can be thus tested by a
steel tape or by a standard chain. Sometimes, it
is convenient to have a permanent test gauge
established where the chain is tested.
56. Testing and Adjustment of Chain
• When the length of a chain is measured at a
pull of 8 kg at 20 0C the length of the chain
should measure 20 m ± 5 mm and 30 m ± 8
mm for 20 m and 30 m long chain shall be
accurate to within 2 mm. Following measures
are taken to adjust the length of a chain.
58. Testing and Adjustment of Chain
If chain is found to be too long
• It can be adjusted by;
• Closing up the joints of the rings if found to be
opened out
• Reshaping damaged rings
• Removing one or more small rings
• Adjusting the links at the end.
59. Testing and Adjustment of Chain
• If the chain is found to be too short
• Straightening the bent links
• Opening the joints of the rings
• Replacing one or more small circular rings by
bigger ones.
• Inserting new rings where necessary.
• Adjusting the links at the end.
60. Measuring Tapes
• Tapes are used for more accurate
measurement. The tapes are classified based
on the materials of which they are made of
such as:
• Cloth or linen tape
• Fibre Tape
• Metallic Tape
• Steel tape
• Invar Tape
62. Measuring Tapes
Cloth or linen Tape
• Linen tapes are closely woven linen and
varnished to resist moisture. They are
generally 10 m, 20 m, 25 m and 30 m long in
length and 12 to 15 mm wide. They are
generally used for offset measurements. These
tapes are light and flexible.
64. Measuring Tapes
• Fibre Glass Tape
• These tapes are similar to linen and plastic
coated tapes but these are made of glass fibre.
The tapes are quite flexible, strong and non-
conductive. These can be used in the vicinity
of electrical equipment. These tapes do not
stretch or shrink due to changes in temperature
or moisture. These tapes are available in length
of 20 m, 30 m and 50 m length.
66. Measuring Tapes
• Metallic Tape
• A linen tape reinforced with brass or copper wires
to prevent stretching or twisting of fibres is called
a metallic tape. As the wires are interwoven and
tape is varnished these wires are visible to naked
eyes. This is supplied in a lather case with a
winding device. Each metre length is divided into
ten parts (decimetres) and each part is further sub-
divided into ten parts. It is commonly used for
taking offset in chain surveying.
68. Measuring Tapes
• Steel Tape
• The steel tape is made of steel ribbon of width
varying from 6 to 16 mm. The commonly
available length are 10 m, 15 m, 20 m, 30 m
and 50 m. It is graduated in metres,
decimetres, and centimetres. Steel tapes are
used for accurate measurement of distances.
70. Measuring Tapes
• Invar Tape
• Invar tape are made of alloy of nickel 36 %
and steel 64 % having very low co-efficient of
thermal expansion. These are 6 mm wide and
generally available in length of 30 m, 50m,
100m. It is not affected by change of
temperature therefore, it is used when high
degree of precesion is required.
72. Arrows
• Arrows are made of tempered steel wire of
diameter 4 mm. one end of the arrow is bent
into ring of diameter 50 mm and the other end
is pointed. Its overall length is 400 mm.
Arrows are used for counting the number of
chains while measuring a chain line. An arrow
is inserted into the ground after every chain
length measured on the ground.
75. Ranging Rods and Offset Rods
• Ranging rods are used for ranging some intermediate
points on the survey line. Ranging rods are generally 2
to 3 m in length and are painted with alternate bands of
black or white or red and white colour with length of
each equalizing 20 cm. The location of any survey
station can be known from long distances only by
means of ranging rods. If the distance is too long, a rod
of length 4.0 to 6.0 m is used and is called ranging pole.
• The offset rod is similar to ranging rod with the
exception that instead of the flag, a hook is provided at
the top for pushing and pulling the chain or the tape. It
is also used for measuring small offsets
80. Laths & Whites
Laths
• Laths are 0.5 to 1.0 m long sticks of soft wood. They
are sharpened at one end and are painted with white or
light colours. They are used as intermediate points
while ranging or while crossing depressions.
Whites
• Whites are the pieces of sharpened thick sticks cut from
the nearest place in the field. One end of the stick is
sharpened and the other end is split. White papers are
inserted in the split to improve the visibility. Whites are
also used for the same purpose as laths
82. Pegs
• Pegs are made of timber or steel and they are
used to mark the position of the station or
terminal points of a survey line. Wooden pegs
are 15 cm long and are driven into the ground
with the help of a hammer.
85. Plumb Bob
• Plumb-bob is used to transfer points on the
ground. It is also used for fixing the
instruments exactly over the station point
marked on the ground by checking the centre
of the instrument whether coincides with the
centre of the peg or station not, by suspending
the plumb-bob exactly at the centre of the
instrument under it. Plumb bob is thus used as
centring aid in theodolites and plane table.
88. Line Ranger
• It is an optical instrument used for
locating a point on a line and hence
useful for ranging. It consists of two
isosceles prisms placed one over the other
and fixed in an instrument with handle.
The diagonals of the prisms are silvered
so as to reflect the rays.
90. Line Ranger
• Its advantage is it needs only one person to
range. The instrument should be occasionally
tested by marking three points in a line and
standing on middle point observing the
coincidence of the ranging rods. If the images
of the two ranging rods do not appear in the
same line, one of the prism is adjusted by
operating the screw provided for it.
92. Line Ranger
• To locate point C on line AB (ref. Fig.) the surveyor
holds the instrument in hand and stands near the
approximate position of C. If he is not exactly on line
AB, the ranging rods at A and B appear separated as
shown in Fig. (b). The surveyor moves to and fro at
right angles to the line AB till the images of ranging
rods at A and B appear in a single line as shown in
Fig. (c). It happens only when the optical square is
exactly on line AB. Thus the desired point C is
located on the line AB.
95. Chain Surveying
• Chain surveying is the type of surveying in which
only linear measurements are taken in the field.
• This type of surveying is done for surveying of
small extent to describe the boundaries of plots of
land and to locate the existing feature on them.
• It is the method of surveying in which the area is
divided into network of triangles and the sides of
the various triangles are measured directly in the
field with a chain or a tape and no angular
measurements are taken.
97. Principles of Chain Surveying
• The principle of chain surveying is to divide the
area into a number of triangles of suitable sides.
As a triangle is the only simple plane geometrical
figure which can be plotted from the length of the
three sides even if the angles are not known. A
network of triangles is preferred to chain
surveying.
• Triangulation is the principle of chain surveying.
If the area to be surveyed is triangle in shape and
if the lengths and sequence of its three sides are
recorded, the plan of the area can be easily drawn.
103. Terms related to Chain
Surveying
Survey Stations
• Survey stations are the points at the beginning
and at the end of a chain line they may also
occur at any convenient position on the chain
line. Such station may be
• Main Stations
• Subsidiary Stations
• Tie Stations
105. Terms related to Chain
Surveying
• Main Station Stations along the boundary of an
area as controlling points are known as ‘Main
Stations’ The lines joining the main station are
called ‘ Main Survey Lines’. The main survey
lines should cover the whole area to be
surveyed. The main stations are denoted by Δ.
106. Terms related to Chain
Surveying
• Subsidiary Stations: Stations which are on
the main survey lines or any other survey lines
are known as ‘ Subsidiary Stations’ these
stations are taken to run subsidiary lines for
dividing the area into triangles, for checking
the accuracy of triangles and for locating
interior details.
107. Terms related to Chain
Surveying
• Tie Stations:
• These stations are also subsidiary stations
taken on the main survey lines. Lines joining
the stations are known as ‘ Tie lines’ Tie lines
are taken to locate interior details.
108. Terms related to Chain
Surveying
Main Survey Lines:
• The line joining the main stations are called
main survey lines or chain lines.
109. Terms related to Chain
Surveying
• Base Line: The line on which the framework of the
survey is built is known as ‘ Base line’. It is the most
important line of the survey. Generally the longest of
the main survey lines is considered as the base line.
This lines should be taken through fairly level ground,
and should be measured very carefully and accurately.
110. Terms related to Chain
Surveying
• Check Line
• The line joining the apex point of a triangle to
some fixed points on its base is known as ‘
Check line’. It is taken to check the accuracy
of the triangle. Sometimes this line helps to
locate interior details.
111. Terms related to Chain
Surveying
• Tie Line
• A line joining tie stations is termed as a tie
line. It is run to take the interior details which
are far away from the main lines and also to
avoids long offsets. It can also serve as check
line.
112. Selection of Survey Station
• The following points should be considered while
selecting survey stations:
• It should be visible from at least two or more
stations.
• As far as possible main lines should run on level
ground.
• All triangles should be well conditioned (No
angle less than 30º).
• Main network should have as few lines as
possible.
113. Selection of Survey Station
• Each main triangle should have at least one
check line.
• Obstacles to ranging and chaining should be
avoided.
• Sides of the larger triangles should pass as
close to boundary lines as possible.
• Trespassing and frequent crossing of the roads
should be avoided
114. Operation in Chain Surveying
• The following operations are involved in chain
surveying.
• Chaining
• Ranging
• Offsetting
• These three operations are done
simultaneously during chain Surveying.
115. Operation in Chain Surveying
Chaining
Chaining on Level Ground
• The method of taking measurement with the help
of chain or tape is termed as chaining.
Chaining involves following operations
• Fixing the stations
• Unfolding the chain
• Ranging
• Measuring the distance (Survey Line)
• Folding the Chain
116. Operation in Chain Surveying
Fixing of Station
• Stations are first of all marked with pegs and
ranging rods to make them visible.
Unfolding of a Chain
• To open a chain, the strap is unfastened and the
two brass handles are held in the left hand and the
bunch is thrown forward with the right hand.
Then one chainmen moves forward by holding the
other handle until the chain is completely
extended.
119. Operation in Chain Surveying
Ranging
• The process of establishing intermediate points
on a straight line between two end points is
known as ranging. Ranging must be done
before a survey line is chained
120. Ranging ( Code of Signals)
Sr. No. Signal by the Surveyor Meaning of the signal to the
assistant
1 Rapid Sweep with right hand Move considerable towards left
2 Slow Sweep with right hand Move slowly towards left
3 Right arm extended Continuously move towards left
4 Right arm up and move to the right Plumb the rod towards left
5 Rapid Sweep with left hand Move considerable towards right
6 Slow Sweep with left hand Move slowly towards right
7 Left arm extended Continuously move towards right
8 Left arm up and move to the right Plumb the rod towards right
9 Both hand above head and brought
down
Ranging is correct
10 Both arm extended horizontally
and brought down quickly
Fix the ranging rod
122. Operation in Chain Surveying
Measuring the distance (Survey Line)
• Two persons are required in this operation, i.e.
Leader and Follower.
• The chainman at the forward end of the chain
who drags the chain forward, is known as the
leader
• The chainmen at the rear end of the chain, who
holds the zero end of the chain at the station, is
known as the follower.
124. Operation in Chain Surveying
• To chain the line, the leader moves forward by dragging the
chain line and taking with him ranging rod and ten arrows.
The follower stands at the starting station by holding the
other end of the chain. When the chain is fully extended, the
leader holds the ranging rod vertically at arms length.
• The follower directs the leader to move his rod to the left or
right until the ranging rod is exactly in the line. Then the
follower holds the zero end of the chain by touching the
station peg.
• The leader stretches the chain by moving it up and down
with both hands, and finally place it on the line. He then
inserts an arrow on the ground at the end of the chain and
mark it with cross.
125. Operation in Chain Surveying
• Again the leader moves forward by dragging the chain
with nine arrows and the ranging rod. At the end of the
chain, he fixes another arrow as before, As the leader
moves further, the follower picks the arrow which were
inserted by the leader. During chaining the surveyor or
an assistant should conduct the ranging operation.
• In this way, chaining is continued, when all the arrows
are inserted the leader has non left with him, the
follower hands over to the leader.
• To measure the fractional length, the leader should drag
the chain beyond the station and the follower should
hold the zero end of the chain at last arrow, then odd
links should be counted.
127. Operation in Chain Surveying
Folding of Chain
• To fold the chain, a chainmen should move
forward by pulling the chain at the middle. Then
the two halves of the chain will come side by side.
After this, commencing from the central position
of the chain, two pairs of links are taken at a time
with the right hand and placed on the left hand
alternately in both directions. Finally the two
brass handles will appear at top. The bunch
should be then fastened by the strap.
129. Operation in Chain Surveying
Chaining on Sloping Ground
• The object of survey is to prepare a plan or a map.
In the plan or a map the distance plotted between
any two points is always a straight line. Even if
the chaining is done on a sloping ground, this
sloping distance is converted into horizontal
equivalent distance while plotting.
• There are two methods of finding out horizontal
distance while on a sloping ground.
• Direct Method
• Indirect Method
130. Operation in Chain Surveying
Direct Method
• This method is also called method of stepping in this method, the
distance is measured in small horizontal stretches. A suitable length of
chain or tape say l1 is taken. The follower holds the zero end of the
tape at a point on the top of the hill or sloping ground. i.e. at point A.
The tape is stretched horizontally from A at small length l1 of 3 to 5 m.
The point at the end of the l1 is dropped and marked on the ground as
a1. From a1, again tape is stretched exactly in a horizontal plane at a
convenient step l2 and drop end of l2 on the ground as b1. Likewise
entire length of line on the sloping ground is measured.
• Finally the total horizontal length of the line AB, i.e. D is obtained
• D= l1 + l2 + l3 + ……… ln
• Where ln= the last step for the given survey line
136. Operation in Chain Surveying
• Indirect Method
• Indirect method involves calculation from the
directly measured length these methods are
briefly explained here.
Method-1
• Horizontal distance of the segment is calculated
by knowing sloping length of the segment and
angle of inclination of that with horizontal.
• The angle of the sloping surface with horizontal
can be known by a simple handy instrument
called as abney’s level
137. Operation in Chain Surveying
• Total Distance D= ∑d = d1 +d2 +….dn, and
• d= l CosӨ for d1 = l1 Cos Ө1
Where,
Ө = angle of sloping surface with horizontal and
l= sloping length.
144. Operation in Chain Surveying
Method 2
• If elevation difference between two terminal point
and the sloping distance between the two terminal
point is known, the horizontal distance H can be
calculated as,
• H= l2 – D2
• Where,
• l= sloping length
• D= Elevation difference between two points
146. Operation in Chain Surveying
Method 3
• This method is also known as hypotenusal allowance
method. The chaining is done on the sloping ground,
but instead of putting the end arrow at the actual end of
the chain, it is put at some advanced distance and that
point is considered as the end of one chain length.
• In this method, the chain of 20 m length ends at point
B. Therefore, sloping length l = 20 m, but the actual
horizontal length (H) is less than 20 m and calculation
is required to calculate horizontal distance based on Ө.
Angle of inclination of ground.
147. Operation in Chain Surveying
• Horizontal distance H= (l + a) Cos Ө ,
Where,
H is intended to make one chain length,
• Therefore ,
• H= (l + a) Cos Ө
Here, AB= one chain length= l= H= 20 m
• Therefore Put H= l= 20 m
• 20= (20 +a) Cos Ө
• 20 Sec Ө= 20 + a
• a= 20 Sec Ө – 20
• a= 20 (Sec Ө – 1)
148. Operation in Chain Surveying
• Where a hypotenusal allowance for 20 m chain
• For a chain other than 20 m length,
• a= l (Sec Ө – 1) where l= length of chain in m
• Thus the arrow is inserted at (l+a) distance on
the ground instead of at the end of chain. Thus
the horizontal distance of this sloping distance
on ground is equal to one chain length.
150. Offsets
• Lateral measurements to chain lines for
locating ground features are known as offsets.
For this purpose
• perpendicular or oblique offsets may be taken .
If the object to be located (say road) is curved
more number of offsets should be taken. For
measuring offsets tapes are commonly used.
151. Offsets
Perpendicular Offsets
• The offsets which are taken perpendicular to
the chain line are termed as perpendicular
offsets. These offsets are taken by holding zero
end of the tape at the object and swinging the
tape on the chain line. The shortest distance
measured from object to the chain line is
usually the perpendicular offset.
153. Offsets
Oblique Offset
• Oblique distance is always greater than
perpendicular distance. All the offsets which
are not taken at the right angle to chain line are
known as oblique offsets.
156. Offsets
• For setting perpendicular offsets any one of the
following methods are used:
• (i) Swinging
• (ii) Using cross staffs
• (iii) Using optical or prism square.
157. Perpendicular Offset by
Swinging
• Chain is stretched along the survey line. An
assistant holds the end of tape on the object.
Surveyor swings the tape on chain line and
selects the point on chain where offset distance
is the least.
• and notes chain reading as well as offset
reading in a field book on a neat sketch of the
object
162. Perpendicular Offsets Using Cross
Staffs
• Three different types of cross staffs used for setting
perpendicular offsets. All cross staffs are having two
perpendicular lines of sights. The cross staffs are
mounted on stand. First line of sight is set along the
chain line and without disturbing setting right angle line
of sight is checked to locate the object.
• With open cross staff (Fig(a)) it is possible to set
perpendicular only, while with French cross staff
• (Fig(b)), even 45º angle can be set. Adjustable cross
staff can be used to set any angle also, since there are
graduations and upper drum can be rotated over lower
drum.
165. Perpendicular Offsets Using Optical
Square and Prism Square
• These instruments are based on the optical
principle that if two mirrors are at angle ‘θ’ to
each other,
• they reflect a ray at angle ‘2θ’. Figure shows a
typical optical square.
175. 3-4-5 Method
• AB is the chain line it is required to erect a
perpendicular at C of the chain line. Establish a pt
D at 3 m distance. 5m & 6m marks are brought to
gather to form a loop .The tape is stretched tight
by fastening the end D and C. The point D is
established such that DE = 5 m and CE= 4 m and
CD = 3 m and DE2 = CD2 + DE2
• i.e. 5 2 = 3 2 + 4 2 = 25 thus Angle DCE = 90 0
• i.e. CE is perpendicular to chain line at C