1. The document provides information on theodolite traversing and describes the parts and functions of a transit vernier theodolite. It discusses how to set up the theodolite over a station and level it up, which are important temporary adjustments.
2. The theodolite is used to measure horizontal and vertical angles precisely and for various surveying applications. It has parts like the telescope, vertical circle, standards, and upper and lower plates.
3. Proper temporary adjustments of the theodolite include setting it up over a station point using a plumb bob, and then leveling the instrument using plate levels and levelling screws.
The document discusses theodolite traversing and defines key terms related to using a transit theodolite. It describes the main components of a transit theodolite including the telescope, vertical circle, plate bubbles, tribrach, and foot screws. It explains how to perform temporary adjustments like centering the theodolite over a station mark and leveling it using the tripod and foot screws. It also provides details on measuring horizontal and vertical angles with a vernier theodolite.
This document discusses the use of a theodolite for surveying. It begins by explaining that a theodolite is needed to precisely measure horizontal and vertical angles, unlike a compass. It then defines theodolite surveying as surveying that measures angles using a theodolite. The document goes on to classify theodolites based on their horizontal axis and method of angle measurement. It describes the basic parts of a transit vernier theodolite and explains terms used in manipulating one. Finally, it discusses methods for measuring horizontal angles, including the general, repetition, and reiteration methods.
The document discusses different types of traverses and methods for conducting traverse surveys. It describes two types of traverses: open traverses that begin and end at points of known and unknown positions, and closed traverses that begin and end at points of known positions, including closed-loop traverses that begin and end at the same point. It also outlines four methods for determining directions during traversing: chain angle method, free needle method, fast needle method, and measuring angles between lines. Finally, it discusses instruments used for measuring angles like compasses and theodolites, and defines different types of bearings including true, magnetic, and arbitrary bearings.
Tacheometric surveying is a method of surveying that determines horizontal and vertical distances optically rather than through direct measurement with a tape or chain. It uses an instrument called a tacheometer fitted with a stadia diaphragm to rapidly measure distances. The key principles are that the ratio of perpendicular to base is constant in similar triangles, allowing horizontal distance and elevation to be calculated from observed angles and staff intercept readings. Common tacheometric systems include fixed hair stadia, subtense stadia, and tangential methods. Distance and elevation formulas are derived for horizontal, inclined, and depressed line of sights depending on staff orientation. Tacheometric surveying is well-suited for difficult terrain where direct measurement is challenging
1. The document presents information from a slideshow on tacheometric surveying. It discusses various methods of tacheometric surveying including fixed hair, movable hair, tangential, and subtense bar methods.
2. Formulas are provided for calculating horizontal distance, vertical distance, and elevation of points using these different tacheometric surveying methods under various sighting conditions such as inclined or depressed lines of sight.
3. The document also discusses tacheometric constants, anallatic lenses, and procedures for conducting field work in a tacheometric survey including selecting instrument stations, taking observations of vertical angles and staff readings, and shifting to subsequent stations.
1) Levelling is the process of determining the relative elevations of points on or near the earth's surface. It is important for engineering projects to determine elevations along alignments.
2) Levelling is used to prepare contour maps, determine altitudes, and create longitudinal and cross sections needed for projects.
3) Key terms include bench mark, datum, reduced level, line of collimation, and height of instrument. Different types of levelling include simple, differential, fly, longitudinal, and cross-sectional levelling.
1. Levelling is used to determine the relative heights of points and establish a common datum. It involves using a level instrument and staff to obtain precise elevation readings.
2. Key terms include benchmarks, backsight, foresight, and intermediate sight readings. Common level instruments are the dumpy level, tilting level, wye level, and automatic level.
3. Levelling methods include simple, differential, fly, check, profile, cross, and reciprocal levelling used for different applications such as construction works. Precise setup and focusing of the instrument are required before taking readings.
Introduction, purpose, principle, instruments, methods of tacheometry, stadia constants, anallatic lens, Subtense bar, field work in tacheometry, reduction of readings, errors and precisions.
The document discusses theodolite traversing and defines key terms related to using a transit theodolite. It describes the main components of a transit theodolite including the telescope, vertical circle, plate bubbles, tribrach, and foot screws. It explains how to perform temporary adjustments like centering the theodolite over a station mark and leveling it using the tripod and foot screws. It also provides details on measuring horizontal and vertical angles with a vernier theodolite.
This document discusses the use of a theodolite for surveying. It begins by explaining that a theodolite is needed to precisely measure horizontal and vertical angles, unlike a compass. It then defines theodolite surveying as surveying that measures angles using a theodolite. The document goes on to classify theodolites based on their horizontal axis and method of angle measurement. It describes the basic parts of a transit vernier theodolite and explains terms used in manipulating one. Finally, it discusses methods for measuring horizontal angles, including the general, repetition, and reiteration methods.
The document discusses different types of traverses and methods for conducting traverse surveys. It describes two types of traverses: open traverses that begin and end at points of known and unknown positions, and closed traverses that begin and end at points of known positions, including closed-loop traverses that begin and end at the same point. It also outlines four methods for determining directions during traversing: chain angle method, free needle method, fast needle method, and measuring angles between lines. Finally, it discusses instruments used for measuring angles like compasses and theodolites, and defines different types of bearings including true, magnetic, and arbitrary bearings.
Tacheometric surveying is a method of surveying that determines horizontal and vertical distances optically rather than through direct measurement with a tape or chain. It uses an instrument called a tacheometer fitted with a stadia diaphragm to rapidly measure distances. The key principles are that the ratio of perpendicular to base is constant in similar triangles, allowing horizontal distance and elevation to be calculated from observed angles and staff intercept readings. Common tacheometric systems include fixed hair stadia, subtense stadia, and tangential methods. Distance and elevation formulas are derived for horizontal, inclined, and depressed line of sights depending on staff orientation. Tacheometric surveying is well-suited for difficult terrain where direct measurement is challenging
1. The document presents information from a slideshow on tacheometric surveying. It discusses various methods of tacheometric surveying including fixed hair, movable hair, tangential, and subtense bar methods.
2. Formulas are provided for calculating horizontal distance, vertical distance, and elevation of points using these different tacheometric surveying methods under various sighting conditions such as inclined or depressed lines of sight.
3. The document also discusses tacheometric constants, anallatic lenses, and procedures for conducting field work in a tacheometric survey including selecting instrument stations, taking observations of vertical angles and staff readings, and shifting to subsequent stations.
1) Levelling is the process of determining the relative elevations of points on or near the earth's surface. It is important for engineering projects to determine elevations along alignments.
2) Levelling is used to prepare contour maps, determine altitudes, and create longitudinal and cross sections needed for projects.
3) Key terms include bench mark, datum, reduced level, line of collimation, and height of instrument. Different types of levelling include simple, differential, fly, longitudinal, and cross-sectional levelling.
1. Levelling is used to determine the relative heights of points and establish a common datum. It involves using a level instrument and staff to obtain precise elevation readings.
2. Key terms include benchmarks, backsight, foresight, and intermediate sight readings. Common level instruments are the dumpy level, tilting level, wye level, and automatic level.
3. Levelling methods include simple, differential, fly, check, profile, cross, and reciprocal levelling used for different applications such as construction works. Precise setup and focusing of the instrument are required before taking readings.
Introduction, purpose, principle, instruments, methods of tacheometry, stadia constants, anallatic lens, Subtense bar, field work in tacheometry, reduction of readings, errors and precisions.
The document defines levelling as determining the relative heights of points. It discusses the principle of obtaining a horizontal line of sight and objectives of finding point elevations and establishing points at required elevations. Different types of levels, staffs, benchmarks, and adjustments are described. Various levelling classifications are defined including simple, differential, profile, check, reciprocal and precise levelling. The key principle of levelling is to obtain a horizontal line of sight to measure staff readings and determine reduced levels of points.
This document provides information about tacheometry, which is a method of surveying that determines horizontal and vertical distances from instrumental observations. It discusses how tacheometry can be used when obstacles make traditional surveying difficult. The key aspects covered include:
- Defining tacheometry and the measurements it provides
- When tacheometry is advantageous over other surveying methods
- The instruments used, including tacheometers and levelling rods
- How horizontal and vertical distances are calculated using constants
- The different types of tacheometer diaphragms and telescopes
- The fixed hair method for taking readings
1) Curves are gradual bends provided in transportation infrastructure like roads, railways and canals to allow for a smooth change in direction or grade.
2) There are two main types of curves - horizontal curves which provide a gradual change in direction, and vertical curves which provide a gradual change in grade.
3) Curves are needed to safely guide vehicles and traffic when changing directions or grades, to improve visibility, and to prevent erosion of canal banks from water pressure.
Curves are used in transportation routes to gradually change direction between straight segments. There are several types of curves including simple, compound, reverse, and transition curves. A simple circular curve connects two tangents with a single arc, and is defined by its radius or degree. Transition curves provide a gradual transition between tangents and circular curves to avoid abrupt changes in grade or superelevation that could cause vehicles to overturn. There are several methods for laying out circular curves, including using offset distances from the long chord between tangent points or measuring deflection angles from the initial tangent.
Levelling, terms related to levelling, methods of levellingMir Zafarullah
Levelling is the branch of surveying that deals with determining elevations and measuring vertical distances. It is important for engineering projects to establish accurate networks of heights. The key principle is obtaining a horizontal line of sight to measure vertical distances of points above or below this line. Common equipment includes dumpy levels, automatic levels, and digital levels. Levelling staffs are used to take readings and determine reduced levels of points. There are different types of levelling operations depending on the project needs.
Contour lines on a map connect points of equal elevation above sea level. They show the shape and features of the land. There are two main methods for creating contour maps - direct and indirect. The direct method precisely traces contours in the field but is slow. The indirect method takes spot elevations across an area and interpolates the contour lines, making it faster but less precise. Common indirect techniques include surveying on a grid, along cross-sections, or using a tacheometer along radial lines. Contour maps provide topographic information for engineering projects.
This document provides an overview of surveying and leveling. It defines surveying as determining the relative positions of points on Earth through direct or indirect measurements. The main objectives of surveying are preparing maps and plans. Leveling is defined as determining relative heights or elevations of points through direct measurement of vertical distances from a reference level. Common instruments used for leveling include a level, tripod, staff, tape, and pegs. Leveling follows the principle of obtaining a horizontal line of sight to measure vertical distances of points above or below this line. Key leveling terms defined include bench mark, height of instrument, backsight, foresight, and change point. Methods for recording level data in a field book are also
Theodolite traversing, purpose and principles of theodolite traversingDolat Ram
The document discusses theodolite traversing, which is a surveying method that uses a theodolite to measure angles and a chain or tape to measure distances between control points called traverse stations.
The theodolite is used to measure horizontal and vertical angles, and there are two main types - optical and electronic digital theodolites. The chain or tape is used to measure distances between traverse stations.
A traverse consists of straight lines connecting traverse stations, with known lengths and angles defined by theodolite measurements. Traverses can be open or closed loops. Theodolite traversing is used for area computation, surveying, data reduction, and indirect measurement of elevations, distances, and
This document provides an overview of basic surveying principles and methods:
1) Surveying works from establishing overall control points before measuring details. Control points are established through precise primary networks of triangles or traverses.
2) Secondary control networks further divide the primary network for less precise work. Survey of details then uses the established control points. This minimizes error accumulation.
3) A traverse connects lines whose lengths and directions are measured to establish a framework. Traverses can be open or closed, with closed traverses returning to the starting point.
4) The direction of lines is defined by their bearing from a reference meridian using different systems like true, magnetic, or arbitrary meridians.
This document discusses the topic of chain surveying for a civil engineering class project. It provides definitions of chain surveying, noting that it involves measuring linear distances between survey stations to divide an area into triangles without taking angular measurements. It then outlines the key principles and terms of chain surveying, such as defining main stations, subsidiary stations, tie stations, main survey lines, base lines, check lines, and tie lines. Finally, it provides the basic procedures for conducting a chain survey between two stations.
This document provides an overview of linear measurements and chain surveying techniques. It discusses different types of ranging methods, including direct and reciprocal ranging, to locate intermediate points along a survey line. It also describes instruments used for chain surveying, such as different types of chains, tapes, arrows, ranging rods, and plumb bobs. The key principle of chain surveying is that it involves measuring the sides of triangles within the survey area using a chain or tape, without taking any angular measurements.
1. Levelling is used to determine relative heights and elevations of points and establish points at required elevations. It involves using instruments like levels and staffs.
2. There are different types of levels (dumpy, tilting, wye, automatic) and staffs (self-reading, target). Precise levelling is done to establish permanent benchmarks.
3. Adjustments must be made to level instruments during setup and permanently. Methods like differential, profile and cross levelling are used depending on the task. Reciprocal levelling involves backsight-foresight exchange to check for errors.
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
The document provides information about theodolites. It begins with an introduction stating that a theodolite is used to measure horizontal and vertical angles more precisely than a magnetic compass. It then discusses the main parts of a theodolite including the horizontal circle, vertical circle, telescope, and levels. The document also covers the history of theodolites from their early origins to modern electronic versions. It describes how to operate a transit vernier theodolite including terms like centering, transiting, swinging the telescope, and changing face. Finally, it discusses the permanent and temporary adjustments needed to ensure accurate theodolite measurements.
Tacheometric surveying uses a tacheometer to determine horizontal and vertical distances through angular measurements. A tacheometer is a theodolite fitted with stadia hairs and an anallatic lens. The tacheometric formula relates the staff intercept, focal length, stadia interval and additive constant to calculate horizontal distances. Methods include stadia, fixed/movable hair, and non-stadia techniques. Determining the tacheometer constant involves measuring distances and staff intervals at stations to solve equations. Errors arise from incorrect stadia intervals or graduations. Tacheometric surveying provides distances in rough terrain but with less precision than other methods.
This document is a field report for a traversing survey conducted by students. It contains unadjusted and average field data from three separate traverses, including measured horizontal and vertical angles between stations. It also shows the calculations to determine angular errors, angle adjustments, course bearings, latitudes and departures, adjusted coordinates, and station positions. The objectives, equipment used, and results are presented in tables and graphs.
The document discusses theodolite traversing and provides definitions and explanations of various parts and adjustments of a transit theodolite. It describes the purpose of a theodolite, defines key terms, and explains how to perform temporary and permanent adjustments of the instrument. Specifically, it outlines how to level the theodolite, set the verniers, and adjust the horizontal and vertical hairs to ensure the line of collimation coincides with the optical axis.
The document defines levelling as determining the relative heights of points. It discusses the principle of obtaining a horizontal line of sight and objectives of finding point elevations and establishing points at required elevations. Different types of levels, staffs, benchmarks, and adjustments are described. Various levelling classifications are defined including simple, differential, profile, check, reciprocal and precise levelling. The key principle of levelling is to obtain a horizontal line of sight to measure staff readings and determine reduced levels of points.
This document provides information about tacheometry, which is a method of surveying that determines horizontal and vertical distances from instrumental observations. It discusses how tacheometry can be used when obstacles make traditional surveying difficult. The key aspects covered include:
- Defining tacheometry and the measurements it provides
- When tacheometry is advantageous over other surveying methods
- The instruments used, including tacheometers and levelling rods
- How horizontal and vertical distances are calculated using constants
- The different types of tacheometer diaphragms and telescopes
- The fixed hair method for taking readings
1) Curves are gradual bends provided in transportation infrastructure like roads, railways and canals to allow for a smooth change in direction or grade.
2) There are two main types of curves - horizontal curves which provide a gradual change in direction, and vertical curves which provide a gradual change in grade.
3) Curves are needed to safely guide vehicles and traffic when changing directions or grades, to improve visibility, and to prevent erosion of canal banks from water pressure.
Curves are used in transportation routes to gradually change direction between straight segments. There are several types of curves including simple, compound, reverse, and transition curves. A simple circular curve connects two tangents with a single arc, and is defined by its radius or degree. Transition curves provide a gradual transition between tangents and circular curves to avoid abrupt changes in grade or superelevation that could cause vehicles to overturn. There are several methods for laying out circular curves, including using offset distances from the long chord between tangent points or measuring deflection angles from the initial tangent.
Levelling, terms related to levelling, methods of levellingMir Zafarullah
Levelling is the branch of surveying that deals with determining elevations and measuring vertical distances. It is important for engineering projects to establish accurate networks of heights. The key principle is obtaining a horizontal line of sight to measure vertical distances of points above or below this line. Common equipment includes dumpy levels, automatic levels, and digital levels. Levelling staffs are used to take readings and determine reduced levels of points. There are different types of levelling operations depending on the project needs.
Contour lines on a map connect points of equal elevation above sea level. They show the shape and features of the land. There are two main methods for creating contour maps - direct and indirect. The direct method precisely traces contours in the field but is slow. The indirect method takes spot elevations across an area and interpolates the contour lines, making it faster but less precise. Common indirect techniques include surveying on a grid, along cross-sections, or using a tacheometer along radial lines. Contour maps provide topographic information for engineering projects.
This document provides an overview of surveying and leveling. It defines surveying as determining the relative positions of points on Earth through direct or indirect measurements. The main objectives of surveying are preparing maps and plans. Leveling is defined as determining relative heights or elevations of points through direct measurement of vertical distances from a reference level. Common instruments used for leveling include a level, tripod, staff, tape, and pegs. Leveling follows the principle of obtaining a horizontal line of sight to measure vertical distances of points above or below this line. Key leveling terms defined include bench mark, height of instrument, backsight, foresight, and change point. Methods for recording level data in a field book are also
Theodolite traversing, purpose and principles of theodolite traversingDolat Ram
The document discusses theodolite traversing, which is a surveying method that uses a theodolite to measure angles and a chain or tape to measure distances between control points called traverse stations.
The theodolite is used to measure horizontal and vertical angles, and there are two main types - optical and electronic digital theodolites. The chain or tape is used to measure distances between traverse stations.
A traverse consists of straight lines connecting traverse stations, with known lengths and angles defined by theodolite measurements. Traverses can be open or closed loops. Theodolite traversing is used for area computation, surveying, data reduction, and indirect measurement of elevations, distances, and
This document provides an overview of basic surveying principles and methods:
1) Surveying works from establishing overall control points before measuring details. Control points are established through precise primary networks of triangles or traverses.
2) Secondary control networks further divide the primary network for less precise work. Survey of details then uses the established control points. This minimizes error accumulation.
3) A traverse connects lines whose lengths and directions are measured to establish a framework. Traverses can be open or closed, with closed traverses returning to the starting point.
4) The direction of lines is defined by their bearing from a reference meridian using different systems like true, magnetic, or arbitrary meridians.
This document discusses the topic of chain surveying for a civil engineering class project. It provides definitions of chain surveying, noting that it involves measuring linear distances between survey stations to divide an area into triangles without taking angular measurements. It then outlines the key principles and terms of chain surveying, such as defining main stations, subsidiary stations, tie stations, main survey lines, base lines, check lines, and tie lines. Finally, it provides the basic procedures for conducting a chain survey between two stations.
This document provides an overview of linear measurements and chain surveying techniques. It discusses different types of ranging methods, including direct and reciprocal ranging, to locate intermediate points along a survey line. It also describes instruments used for chain surveying, such as different types of chains, tapes, arrows, ranging rods, and plumb bobs. The key principle of chain surveying is that it involves measuring the sides of triangles within the survey area using a chain or tape, without taking any angular measurements.
1. Levelling is used to determine relative heights and elevations of points and establish points at required elevations. It involves using instruments like levels and staffs.
2. There are different types of levels (dumpy, tilting, wye, automatic) and staffs (self-reading, target). Precise levelling is done to establish permanent benchmarks.
3. Adjustments must be made to level instruments during setup and permanently. Methods like differential, profile and cross levelling are used depending on the task. Reciprocal levelling involves backsight-foresight exchange to check for errors.
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
The document provides information about theodolites. It begins with an introduction stating that a theodolite is used to measure horizontal and vertical angles more precisely than a magnetic compass. It then discusses the main parts of a theodolite including the horizontal circle, vertical circle, telescope, and levels. The document also covers the history of theodolites from their early origins to modern electronic versions. It describes how to operate a transit vernier theodolite including terms like centering, transiting, swinging the telescope, and changing face. Finally, it discusses the permanent and temporary adjustments needed to ensure accurate theodolite measurements.
Tacheometric surveying uses a tacheometer to determine horizontal and vertical distances through angular measurements. A tacheometer is a theodolite fitted with stadia hairs and an anallatic lens. The tacheometric formula relates the staff intercept, focal length, stadia interval and additive constant to calculate horizontal distances. Methods include stadia, fixed/movable hair, and non-stadia techniques. Determining the tacheometer constant involves measuring distances and staff intervals at stations to solve equations. Errors arise from incorrect stadia intervals or graduations. Tacheometric surveying provides distances in rough terrain but with less precision than other methods.
This document is a field report for a traversing survey conducted by students. It contains unadjusted and average field data from three separate traverses, including measured horizontal and vertical angles between stations. It also shows the calculations to determine angular errors, angle adjustments, course bearings, latitudes and departures, adjusted coordinates, and station positions. The objectives, equipment used, and results are presented in tables and graphs.
The document discusses theodolite traversing and provides definitions and explanations of various parts and adjustments of a transit theodolite. It describes the purpose of a theodolite, defines key terms, and explains how to perform temporary and permanent adjustments of the instrument. Specifically, it outlines how to level the theodolite, set the verniers, and adjust the horizontal and vertical hairs to ensure the line of collimation coincides with the optical axis.
This document provides an overview of theodolites and their use in surveying. It discusses how theodolites are used to measure both horizontal and vertical angles. A theodolite is an instrument designed specifically for angular measurement and is one of the most versatile survey equipment. Modern theodolites can measure angles to within 0.1 seconds of arc. The document describes the basic components of an optical theodolite, including the tribrach, horizontal and vertical circles, telescope, and methods for setting up and using a theodolite to obtain angle measurements.
Mass diagram and its characeristics .pptNITINSURESH30
The document discusses the use of a theodolite for surveying. It describes the main parts of a theodolite including the levelling head, horizontal and vertical circles, telescope, plate levels, and clamps. It also defines important terms used when manipulating a transit vernier theodolite such as centering, transiting, swinging the telescope, and changing face. The theodolite is used to measure horizontal and vertical angles which is important for tasks like setting out grades, locating points, and tacheometric surveying.
The document discusses theodolite surveying. It defines theodolite surveying as surveying that measures angles using a theodolite instrument. It describes the main components of a theodolite including the trivet, lower plate, upper plate, telescope, and vertical and horizontal circles. It explains the different types of theodolites based on their method of measuring angles, such as vernier theodolites and micrometer theodolites. It also outlines the common uses and procedures for taking measurements with a theodolite.
The document discusses various surveying techniques including trigonometric leveling, tacheometry, aerial photogrammetry, and curve surveying. It provides definitions and procedures for measuring horizontal and vertical angles using a theodolite. It also describes adjusting theodolites, focusing the eyepiece, and leveling the instrument. Tacheometry is introduced as a method to determine horizontal and vertical distances through angular observations. Applications of aerial photography for engineering projects are outlined. Finally, it covers setting out simple and compound curves, as well as transition curves.
The document discusses theodolite surveying and the use of a theodolite to measure horizontal and vertical angles more precisely than a compass. It defines theodolite surveying as surveying that measures angles using a theodolite. It also describes the basic parts and functions of a transit vernier theodolite, how to manipulate it, adjustments that need to be made, and methods for measuring horizontal angles.
Introduction, definitions, the Vernier transit theodolite, temporary and permanent adjustment of theodolite, measuring horizontal and vertical angles, methods of traversing, closing error, computation of latitudes and departure, check in closed and open traverse, balancing of traverse, Gale’s table.
This document provides an overview of theodolite surveying and the main parts of a theodolite. It discusses how a theodolite can measure both horizontal and vertical angles, allowing surveyors to triangulate object positions. The key parts of a theodolite are then described in detail, including the telescope, horizontal and vertical scales, support frame, upper and lower plates, plate levels, leveling and shifting heads, magnetic compass, tripod, and plumb bob. In total, the document outlines the function and use of theodolites for surveying applications and identifies the primary components that make up a theodolite.
This document provides information about the theodolite including its main parts, how to measure horizontal and vertical angles, methods for traversing, and how to compute latitudes and departures. It discusses sources of errors in theodolite measurements and how to balance a traverse using Bowditch's rule. It also includes an example problem to calculate latitudes, departures, and closing error for a given traverse and adjust it.
This document provides information on leveling and contouring. It defines leveling as determining the relative height of points and describes the principle of leveling as obtaining a horizontal line of sight. It discusses various leveling terms, instruments including dumpy levels, staffs, and methods such as simple and differential leveling. The document also covers reducing levels using methods like height of instrument and rise and fall. It defines contours as lines of equal elevation and contour interval as the vertical distance between contours.
The document provides details of a survey camp conducted in Manali in 2019. It includes the name, roll number, semester and college of the student. It then lists the various practicals covered in the camp, including plane table surveying using radiation and intersection methods, studying the parts and level reduction of a dumpy level, measuring angles using a theodolite, traversing an area and plotting it, and measuring horizontal angles using reiteration. It provides details of each practical, explaining concepts and procedures.
This document describes the components and use of a vernier theodolite surveying instrument. It discusses the main parts including the horizontal and vertical circles, telescope, and levels. It explains how to measure horizontal and vertical angles, compute latitudes and departures, and adjust a traverse using Bowditch's rule. The document also discusses sources of errors and provides an example problem to calculate latitudes, departures, and closing error for a traverse.
The document discusses the theodolite, an instrument used to measure horizontal and vertical angles. It has three main assemblies - the levelling head, horizontal circle, and telescope. The main parts include the horizontal and vertical circles, verniers, clamps and screws. It describes how to measure horizontal and vertical angles using the theodolite. Sources of error and methods to balance a traverse are also outlined.
1. The document discusses various form measurement principles and methods including straightness, flatness, thread measurement, gear measurement, surface finish measurement, and roundness measurement.
2. Thread measurement involves measuring various thread elements like major diameter, minor diameter, pitch, and form using methods such as thread plug gauges, thread wires, and thread micrometers.
3. Gear measurement includes measuring parameters like pitch, lead, backlash, tooth thickness, and errors using equipment such as involute measuring machines, gear tooth vernier calipers, and gear testers.
4. Surface finish is measured using various instruments that analyze surface texture parameters like average roughness, peak-valley height, and form factor.
The document discusses various form measurement principles and methods including thread measurement, gear measurement, straightness measurement, flatness measurement, and surface finish measurement. It provides details on measuring various elements of threads such as major diameter, minor diameter, pitch diameter, and pitch using methods like thread gauges, thread measuring machines, and micrometers. Measurement of gears is also summarized, including terminology, common errors in gears, and using devices like the involute measuring machine and Parkinson gear tester. Straightness and flatness measurement methods like spirit levels, straight edges, and laser systems are also outlined.
1. The document discusses various form measurement principles and methods including straightness, flatness, thread measurement, gear measurement, surface finish measurement, and roundness measurement.
2. Thread measurement involves measuring various thread elements like major diameter, minor diameter, pitch, and form using methods such as thread plug gauges, thread wires, and thread micrometers.
3. Gear measurement includes measuring parameters like pitch, lead, backlash, tooth thickness, and errors using equipment such as involute measuring machines, gear tooth vernier calipers, and gear testers.
4. Surface finish is measured using techniques like stylus probes, profilometers, and comparisons to standard samples which analyze roughness parameters like Ra
Two way slabs are slabs that are supported on all four edges and have a ratio of less than 2 between their long and short spans. This causes them to bend in both directions. There are two types: simply supported and restrained. Simply supported slabs have corners that lift up under loading while restrained slabs have corners that are held down, producing torsion. Reinforcement is provided differently depending on the type of slab.
This document discusses one way slabs. It defines one way slabs as slabs supported by beams on two opposite sides, with the load transferred to the two supports. For a slab to be considered one way, the ratio of its long side (ly) to short side (lx) must be greater than or equal to 2. Reinforcement in a one way slab is provided only along the short span direction. In contrast, two way slabs have reinforcement in both directions since for them ly/lx is less than 2. Other types of slabs discussed include flat slabs supported directly on columns and grid slabs supported within a column-free area by perimeter beams.
The document discusses different types of columns based on bracing, length, and reinforcement. It describes braced and unbraced columns, long and short columns, and tied, spiral, and composite columns. Requirements for minimum reinforcement, lateral ties, and selection of column size are also summarized.
This document discusses development length and lap length in structural design. It defines development length as the length of reinforcement embedded in concrete required to develop the bond stress. A formula for calculating development length is provided based on bar diameter, steel stress, and design bond stress in concrete. Design bond stress values for different concrete grades are also given. Lap length refers to the overlapping length of bars and must be equal to or greater than the development length or 24 times the bar diameter, whichever is greater.
This document provides information on the analysis of T-beams, including:
1) It defines T-beams and L-beams as beams with flanges projecting from one or both sides of the web, forming a T or inverted L shape.
2) It explains the concept of a T-beam as a combination of a rectangular beam and slab portion, and provides the formula to calculate the overall depth.
3) It shows the stress-strain diagram for a T-beam and defines terms like neutral axis, compression and tension forces, and lever arms.
4) It describes how to determine the position of the neutral axis based on the relative magnitudes of compression and tension forces.
This document provides information on doubly reinforced concrete beams. It introduces the concept of doubly reinforced beams, which have reinforcement in both the tension and compression zones. This allows for an increased moment of resistance compared to singly reinforced beams. The key advantages of doubly reinforced beams are that they can be used when the applied moment exceeds the capacity of a singly reinforced beam, when beam depth cannot be increased, or when reversal of stresses may occur. The document includes stress diagrams, design concepts, and differences between singly and doubly reinforced beams.
This document describes methods of trigonometric leveling to determine the elevation of points. It discusses using a theodolite to measure vertical angles and calculate heights based on trigonometric functions. The key methods covered are:
1. Direct and reciprocal methods of observation between two stations to eliminate corrections.
2. Determining heights when the base is accessible or inaccessible using one or two instrument stations, applying corrections for curvature and refraction based on distance.
3. Calculating heights when instrument stations are at different elevations, providing equations to solve for distance and elevation.
This document provides information about circular curves used in highways and railways. It discusses the different types of curves including simple, compound, and reverse curves. It defines key elements of circular curves such as radius, deflection angle, tangent length, and mid-ordinate. It presents the relationships between radius and degree of curvature. Finally, it describes various methods for setting out circular curves in the field, including linear methods using offsets and angular methods using a theodolite.
This document discusses stress diagrams and design considerations for singly reinforced concrete beams. It covers notation, stress conditions, types of failure, and formulas for moment of resistance. The key points are:
1) A stress diagram shows the compression and tension zones of a beam based on the depth of the neutral axis. The moment of resistance depends on the neutral axis location.
2) Beam sections can be balanced, under-reinforced, or over-reinforced depending on when concrete or steel yields. Under-reinforced sections are preferred.
3) Formulas are provided to calculate the moment of resistance based on the steel or concrete stresses for different section types. Reinforcement criteria specify minimum and maximum steel ratios.
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Networking is a telecommunications network that allows computers to exchange data. In
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The aim of this project is to provide the complete information of the National and
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Theodolite traversing
1. THEODOLITE TRAVERSING
Mahatma Gandhi Institute Of
Technical Education
& Research Centre, Navsari (396450)
SURVEYING
4TH SEMESTER
CIVIL ENGINEERING
PREPARED BY:
Asst. Prof. GAURANG PRAJAPATI
CIVIL DEPARTMENT
2. INTRODUCTION
• Theodolite is used to measure the horizontal and vertical angles.
• When the objects are at a considerable distance or situated at a considerable
elevation or depression ,it becomes necessary to measure horizontal and vertical
angles more precisely. So these measurements are taken by a instrument known
as a theodolite.
• Theodolite is more precise than chain survey, magnetic compass or plane table.
THEODOLITE TRAVERSING
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2
3. THEODOLITE TRAVERSING
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APPLICATION OF THEODOLITE
• Measuring horizontal and vertical angles.
• Locating points on a line.
• Prolonging survey lines.
• Finding difference of level.
• Setting out grades
• Ranging curves
• Tacheometric Survey
3
4. [A] Based on movement of telescope on horizontal axis in a vertical plane
1. Transit Theodolite
2. Non Transit Theodolite
[B] Based on an arrangement to measure the angles
1. Vernier Theodolite
2. Micro meter Theodolite
3. Electronic Digital Theodolite
4
CLASSIFICATION OF THEODOLITES
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4
5. 1. Transit Theodolite
• In case of a transit theodolite, the line of sight can be reversed by revolving the
telescope through 180 degree in the vertical plane.
• Internal focusing telescope is used in this theodolite.
• These theodolites are mainly used for surveying.
2. Non Transit Theodolite
• In case of a transit theodolite, the telescope can not be revolved round the
horizontal axis in a vertical plane completely.
• It can be rotated in a vertical plane for some limited angle.
• These theodolites have now become obsolete.
[A] Based on movement of telescope on horizontal axis in
a vertical plane
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5
6. 1. Vernier Theodolite
• The theodolite in which Vernier is fitted to measure the angles, is called Vernier Theodolite.
• It can measure an angle up to 20”.
2. Micrometer Theodolite
• The theodolite in which Micrometer is fitted to measure the angles, ,is called Micrometer Theodolite.
• It can measure an angle up to 1”.
• It gives more accuracy.
3. Elecronic Digital Theodolite
• In Elecronic Digital Theodolite, the reading of angle is obtained in digital form.
• When E.D.M. (Electronic Distance Measuring) instrument is attached to the Elecronic Digital Theodolite,
it becomes TOTAL STATION.
6
[B] Based on an arrangement to measure the angles
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6
7. • The diameter of the graduated circle on the lower plate indicates the size of
theodolite.
• For ordinary surveying works, theodolites of 8-12 cm size are used.
• For Triangulation survey and other accurate survey works, theodolites of larger size
are used.
• For Indian Triangulation survey, a theodolite of 91.4 cm (36”) diameter was used.
7
SIZE OF THEODOLITE
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7
8. • PARTS OF THEODOLITE
• Telescope
• Vertical circle
• Index frame
• The standards
• The upper plate
• The lower plate
• The levelling head
• The shifting head
• Plate level
• Tripod
• Plumb bob
• Magnetic compass
TRANSIT VERNIER THEODOLITE
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12. PARTS OF THEODOLITE AND THEIR FUNCTIONS
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Telescope
A telescope is a focusing instrument which has object piece at one end and eye piece
at the other end. It rotates about horizontal axis in vertical plane. The graduations are
up to an accuracy of 20’.
Vertical Circle
Vertical circle is fitted to telescope and moves simultaneously with telescope. It has
graduation in each quadrant numbered from 0 to 90degrees.
The Standards
The standards are the frames which supports telescope and allow it to rotate about
vertical axis. Generally, these are in letter A-shape. So, standards are also called as A-
frame.
12
13. Levelling Head
• The levelling head contains two parallel triangular plates called as tribrach plates.
• The upper one is known as upper tribrach plate and is used to level the upper plate
and telescope with the help of levelling screws provided at its three ends.
• The lower one is called as lower tribrach plate and is attached to the tripod stand.
It has a circular hole through which a plumb bob may be suspended.
Function of Levelling head
• To support the main part of the instrument.
• To attach the theodolite to the tripod.
• To provide a mean for levelling the theodolite.
PARTS OF THEODOLITE AND THEIR FUNCTIONS
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14. PARTS OF THEODOLITE AND THEIR FUNCTIONS
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Two spindles or axis
• The inner spindle or axis is solid and conical.
• The outer spindle or axis is hollow and ground conical in the interior.
• The inner spindle is also called the upper axis since it carries the Vernier or upper
plate.
• The outer spindle carries the scale or lower plate.
• Both the axes have a common axis which form the vertical axis of the instrument.
14
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PARTS OF THEODOLITE AND THEIR FUNCTIONS
15
Lower Plate (Scale plate)
• This is also called as scale plate because it contains a scale on which 0 to 360
readings are graduated.
• It is attached to the outer spindle and consists lower clamping screw.
• If lower clamp screw is loosened and upper clamp screw is tightened, both plates
can rotate together.
• Similarly, if lower clamping screw is tightened and upper clamp is loosened then,
only upper plate is movable and lower plate is fixed with tribrach plate.
16. THEODOLITE TRAVERSING
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PARTS OF THEODOLITE AND THEIR FUNCTIONS
16
Upper Plate (Vernier plate)
• The top surface of upper plate gives support to the standards.
• It also consists an upper clamping screw with respect to tangents screw which
helps to fixing it to the lower plate.
• When the upper clamping screw is tightened both upper and lower plates are
attached and moved together with some relative motion because of upper tangent
screw.
• The upper plate also consists two verniers with magnifiers which are arranged
diagonally. It is attached tow inner spindle.
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PARTS OF THEODOLITE AND THEIR FUNCTIONS
17
Upper and lower clamp screw
• The upper plate carries an upper clamp screw and a corresponding tangent screw.
• The upper plate can be fixed to the lower plate by tightening the upper clamp
screw.
• The upper plate can be slightly rotated for adjustment with the help of the upper
tangent screw.
• The lower plate carries a lower clamp screw and a lower tangent screw.
• When the lower clamp screw is tightened, the lower plate is fixed to the upper
plate and it can be rotated slightly for adjustment with the help of the lower
tangent screw.
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PARTS OF THEODOLITE AND THEIR FUNCTIONS
18
Level tubes or plate levels
• The upper plate carries two level tubes, also known as plate levels, at right angles to
each other.
• One of the level tube is kept parallel to the trunnion axis.
• The spirit level is can be centred with the help of the foot screw.
Plumb Bob
• Plumb bob is tool having a cone shaped weight attached to a long thread.
• A plumb bob is suspended from the hook fitted to the bottom of the vertical axis.
• It is used to centre the instrument exactly over a station point.
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PARTS OF THEODOLITE AND THEIR FUNCTIONS
19
Compass
• The theodolite may contain circular compass or through compass or tubular compass
box in the centre of upper plate.
• It is used to take bearings.
• It is fitted to the A – frame.
Shifting head
• An arrangement is of Shifting head is made for quick and accurate centring of the
theodolite.
• By this arrangement, the theodolite can be shifted in the horizontal plane with respect
to the tripod head, to bring the plumb bob exactly over the station peg.
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PARTS OF THEODOLITE AND THEIR FUNCTIONS
20
Clip Screw
• It is fitted at the lower end of clipping arm for slightly rotating the index arm for adjustment.
• When the telescope is moved in the vertical plane, the vertical circle moves relative to the
verniers and thus readings are taken.
• For adjustment purpose, however, the index arm can be rotated slightly with the help of a clip
screw.
Altitude level tube
• Some theodolites are provided with altitude level tube fitted over the telescope.
• It is used to test the horizontality of the trunnion axis.
• The bubble of the altitude level tube can be centred by clip screw.
21. THEODOLITE TRAVERSING
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FUNCTION OF CLAMP SCREW AND TANGENT SCREW IN
THEODOLITE
21
• Clamp screw
• When the upper clamping screw is tightened but the lower clamp screw is loose,
the instrument rotates on its outer axis, without any relative movement between
the two plates. It is called lower motion. In this case, there is no change in vertical
reading.
• When the lower clamping screw is tightened but the upper clamp screw is loose,
the instrument rotates on its inner axis, with any relative movement between the
Vernier and the scale.. It is called upper motion. In this case, there is change in
vertical reading.
• When both upper clamp screw and lower clamp screw are tightened, the
instrument cannot rotate at all.
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FUNCTION OF CLAMP SCREW AND TANGENT SCREW IN
THEODOLITE
22
• Tangent screw
• The upper plate carries an upper tangent screw and the lower plate carries an lower
tangent screw.
• For small movements of plates (Fine adjustment), corresponding tangent screw are
used.
• Before using any tangent screw, the corresponding clamp screw must be tightened.
• Thus,
After clamping the upper clamp, fine adjustment of upper plate for bisecting the target
(Ranging rod) can be made by rotating the upper tangent screw.
After clamping the lower clamp, fine adjustment of lower plate for bisecting the target
(Ranging rod) can be made by rotating the lower tangent screw.
23. THEODOLITE TRAVERSING
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DEFINITIONS AND TECHNICAL TERMS
23
• VERTICAL AXIS
It is the axis about which the telescope can be rotated in a horizontal plane.
It is also known as the azimuth axis.
This is the axis about which the lower and upper plate rotate.
• HORIZONTAL AXIS (TRUNNION AXIS)
It is the axis about which the telescope and the vertical circle can be rotated in a
vertical plane.
• LINE OF SIGHT OR LINE OF COLLIMATION
It is the imaginary line passing through the intersection of the cross hairs of the
diaphragm and the optical centre of the objective.
• AXIS OF THE TELESCOPE
It is the line joining the optical centre of the object glass to the centre of the eye-piece.
24. THEODOLITE TRAVERSING
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DEFINITIONS AND TECHNICAL TERMS
24
• FACE LEFT:
When the vertical circle is to the left side of the observer, then the position of the theodolite is called
face left.
• FACE RIGHT:
When the vertical circle is to the right side of the observer, then the position of the theodolite is called
face right.
• TRANSITING:
It is the process of turning the telescope in vertical plane through 180o about the trunnion axis.
It is also known as plunging or reversing.
In case of transiting, the position of object glass and eye-piece are interchanged and the line of sight is
reversed.
• SWINGING THE TELESCOPE:
It means turning the telescope about its vertical axis in the horizontal plane.
If the telescope is rotated in clockwise direction, it is known as right swing.
If the telescope is rotated in anticlockwise direction, it is known as left swing.
25. THEODOLITE TRAVERSING
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DEFINITIONS AND TECHNICAL TERMS
25
• TELESCOPE NORMAL
A telescope is said to be normal, when the vertical circle is to the left of the observer.
• TELESCOPE INVERTED
A telescope is said to be inverted, when the vertical circle is to the right of the
observer.
• CHANGING FACE:
It is an operation of bringing the face of the telescope from left to right and vice-versa.
• AXIS OF THE LEVEL TUBE
The axis of the level tube or the bubble line is the straight line tangential to the
longitudinal curve of the level tube at its centre.
The axis of the level tube is horizontal when the bubble is at centre.
26. THEODOLITE TRAVERSING
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TEMPORARY ADJUSTMENT OF A THEODOLITE
26
• Temporary adjustments are the adjustments which are required to be made at
each setting of the instrument before taking observations.
• These adjustments are also known as station adjustments.
• There are three temporary adjustments of a theodolite.
1. Setting up the theodolite over a station.
2. Levelling up.
3. Elimination of parallax.
27. THEODOLITE TRAVERSING
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TEMPORARY ADJUSTMENT OF A THEODOLITE
27
1. SETTING UP AND CENTRING
Procedure:
• Place the tripod over the station. The legs of the tripod should be spread so that they make an angle of
60o with horizontal.
• Take out the instrument from the box. Lift the instrument from the base and screw it firmly on the
tripod head.
• Adjust the height of the tripod so that the telescope is at a convenient height.
• Suspend a plumb bob from the hook beneath the inner spindle.
• Approximate centring is done by means of the tripod legs. The tripod legs are moved radially or
circumferentially for centring. Sometimes he instrument and the tripod have to be moved bodily for
centring to bring the plumb bob over the station mark.
• In modern theodolites, the shifting head is provided for easy and accurate setting up of the instrument.
• The approximate levelling is done either with reference to a small circular bubble tube provided on
tribrach or is done by eye adjustment.
28. THEODOLITE TRAVERSING
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TEMPORARY ADJUSTMENT OF A THEODOLITE
28
2. LEVELING UP:
• The purpose of the levelling is to make the vertical axis shall be truly vertical.
• Accurate levelling of the theodolite is done with the help of levelling screws or foot
screw with reference to the plate levels.
Procedure:
• Turn the upper plate until the longitudinal axis of the plate level is roughly parallel to a
line joining any two of the levelling screws (A & B).
29. THEODOLITE TRAVERSING
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TEMPORARY ADJUSTMENT OF A THEODOLITE
29
• Hold these two levelling screws between the thumb and first finger of each hand uniformly so that the thumb
moves either towards each other or away from each other until the bubble comes to the centre.
• Turn the upper plate through 90º i.e. until the axes of the level passes over the position of the third levelling
screw ‘C’.
• Turn this levelling screw until the bubble comes to the centre.
• Rotate the upper plate through 90º to its original position fig (a) and repeat step (2) till the bubble comes to the
centre.
• Turn back again through 90º and repeat step 4.
• Repeat the steps 2 and 4 till the bubble is central in both the positions.
• Now rotate the instrument through 180º. The bubble should be remaining in the centre of its run, provided it is
in correct adjustment. The vertical axis will then be truly vertical.
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TEMPORARY ADJUSTMENT OF A THEODOLITE
30
3. ELIMINATION OF PARALLAX:
• Parallax is a condition arising when the image formed by the objective is not in the plane of the cross hairs.
• Unless parallax is eliminated, accurate sighting is not possible. Parallax can be eliminated in two steps.
Focusing of eye-piece.
• The eye piece is focused to make the cross hairs distinct and clear.
Procedure
• Point the telescope to the sky or hold a piece of white paper in front of telescope.
• Move the eye-piece in and out until a distinct sharp black image of the cross-hairs is seen.
• This confirms proper focusing.
Focusing of object glass.
• The objective is focussed to bring the image of the object in the plane of cross hairs.
Procedure
• First, direct the telescope towards the object for observation.
• Next, turn the focusing screw until the image of the object appears clear and sharp as the observer looks through properly focused eye-
piece.
• When focusing has been done properly, there will be no parallax i.e., there will be no apparent movement of the image relative to the cross
hairs when the observer moves his eye from one side to the other or from top to bottom.
31. THEODOLITE TRAVERSING
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FUNDEMENTAL AXES OF THEODOLITE
31
The fundamental axis of theodolite are:
• Vertical axis
• Trunnion axis
• Line of collimation
• Altitude level axis
• Axis of plate level
A theodolite is said to be in proper condition if the following conditions are
satisfied:
• The axis of the plate is perpendicular to the vertical axis
• The trunnion axis is perpendicular to the vertical axis
• The line of collimation is perpendicular to the trunnion axis
• The axis of the altitude level is parallel to the line of collimation
33. THEODOLITE TRAVERSING
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MEASUREMENT OF HORIZONTAL ANGLE
33
1. General Method
• Set up the theodolite at station point O and level it accurately.
• Set the vernier A to the zero or 3600 of the horizontal circle. Tighten the upper clamp.
• Loosen the lower clamp. Turn the instrument and direct the telescope towards A to
bisect it accurately with the use of tangent screw. After bisecting accurately check the
reading which must still read zero. Read the vernier B and record both the readings.
• Loosen the upper clamp and turn the telescope clockwise until line of sight bisects
point B on the right hand side. Then tighten the upper clamp and bisect it accurately
by turning its tangent screw.
BA
O
34. THEODOLITE TRAVERSING
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MEASUREMENT OF HORIZONTAL ANGLE
34
• Read both verniers. The reading of the vernier a which was initially set at zero gives
the value of the angle AOB directly and that of the other vernier B by deducting
1800 .The mean of the two vernier readings gives the value of the required angle
AOB.
• Change the face of the instrument and repeat the whole process. The mean of the
two vernier readings gives the second value of the angle AOB which should be
approximately or exactly equal to the previous value.
• The mean of the two values of the angle AOB ,one with face left and the other with
face right ,gives the required angle free from all instrumental errors.
35. THEODOLITE TRAVERSING
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MEASUREMENT OF HORIZONTAL ANGLE
35
2. Repetition Method
• The method of repetition is used to measure a horizontal angle to a finer degree of
accuracy.
• By this method, an angle is measured two or more times by allowing the vernier to
remain clamped each time at the end of each measurement instead of setting it back at
zero when sighting at the previous station.
• Thus an angle reading is mechanically added several times depending upon the number
of repetitions.
• The average horizontal angle is then obtained by dividing the final reading by the
number of repetitions.
• For very accurate work the method of repetition is used.
36. THEODOLITE TRAVERSING
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MEASUREMENT OF HORIZONTAL ANGLE
36
PROCEDURE:
• Select a station point O.
• Set the theodolite at O and do the temporary adjustments. The
telescope is adjusted for right face right swing.
• Set the vernier A to zero using upper clamp. Loosen the lower clamp,
direct the telescope to the station point A and bisect A exactly by
using the lower clamp and lower tangent screw.
• Note the vernier readings (A and B).
• Loosen the upper clamp and turn the telescope clockwise until the
point B is exactly bisected.
• Note the vernier readings (A and B).
• The mean of the two vernier readings gives the value of <AOB.
A
O
B
37. THEODOLITE TRAVERSING
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MEASUREMENT OF HORIZONTAL ANGLE
37
• Loosen the lower clamp and turn the telescope to station point A and bisected A by
using the lower clamp and lower tangent screw.
• Loosen the upper clamp and turn the telescope clockwise until the point B is exactly
bisected. Now the vernier reading is twice the value of the angle.
• Repeat the process for the required number of times (usually 3).
• The correct value of the angle AOB is obtained by dividing the final reading by the
number of repetition.
• Adjust the telescope for left face left swing.
•
Repeat the whole process by turning the telescope in anticlockwise
direction.
Take the average of face left and faces right observation to give the
horizontal angle AOB.
38. THEODOLITE TRAVERSING
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MEASUREMENT OF HORIZONTAL ANGLE
38
• 3. Reiteration Method
• Reiteration is a method of measuring horizontal angles with high precision.
• It is less tedious and is generally preferred when there are several angles to be
measured at a station.
• Several angles are measured successively and finally the horizon is closed.
• Closing the horizon is the process of measuring the angles around a point to obtain
a check on their sum which should be equal to 360o.
39. THEODOLITE TRAVERSING
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MEASUREMENT OF HORIZONTAL ANGLE
39
PROCEDURE:
• Select a station point O.
• Set the Theodolite at O and do the
temporary adjustments. The telescope is
adjusted for right face right swing.
• Set the vernier A to zero using upper clamp.
Loosen the lower clamp, direct the
telescope to the station point A and bisect A
exactly by using the lower clamp and lower
tangent screw.
• Note the vernier readings (A and B).
• Loosen the upper clamp and turn the
telescope clockwise until the point B is
exactly bisected.
• Note the vernier readings (A and B).
A B
C
D
40. THEODOLITE TRAVERSING
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MEASUREMENT OF HORIZONTAL ANGLE
40
• The mean of the two vernier readings gives the value of <AOB.
• Bisect all the points successively and note the readings of both venires at each
bisection.
• Finally close the horizon by sighting the station point A. The A vernier should be
3600. If not, note the closing error.
• Adjust the telescope for left face left swing.
• Repeat the whole process by turning the telescope in anticlockwise direction.
• Distribute the closing error proportionately the several observed angles.
• Take the average of face left and face right observations to give the corresponding
horizontal angles.
41. THEODOLITE TRAVERSING
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MEASUREMENT OF VERTICAL ANGLE
41
• Vertical Angle
A vertical angle is an angle between the inclined line of sight and the horizontal.
It may be an angle of elevation or depression according as the object is above or
below the horizontal plane.
B
O
A
B
O
HORI. LINE
O
HORI.
LINE
β
HORI. LINE
VERTICAL ANGLE
A
Fig.a
Fig. b Fig. c
B
A
AOB= α+ β
AOB= α - β
β
β
α
α
α
42. THEODOLITE TRAVERSING
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MEASUREMENT OF VERTICAL ANGLE
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ToMeasure the Vertical Angle of an object A at a station O
• Set up the theodolite at station point O and level it accurately with reference to the
altitude bubble.
• Set the zero of vertical vernier exactly to the zero of the vertical circle clamp and
tangent screw.
• Bring the bubble of the altitude level in the central position.
• The line of sight is thus made horizontal and vernier still reads zero.
• Loosen the vertical circle clamp screw and direct the telescope towards the object A
and sight it exactly by using the vertical circle tangent screw.
• Read both verniers on the vertical circle, The mean of the two vernier readings gives the
value of the required angle.
• Change the face of the instrument and repeat the process. The mean of the two vernier
readings gives the second value of the required angle.
• The average of the two values of the angles thus obtained, is the required value of the
angle free from instrumental errors.
43. THEODOLITE TRAVERSING
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MEASUREMENT OF VERTICAL ANGLE
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For measuring Vertical Angle between two points A &B
• Sight A as before , and take the mean of the two vernier readings at the vertical
circle. Let it be α.
• Similarly, sight B and take the mean of the two vernier readings at the vertical
circle. Let it be β.
• The sum or difference of these readings will give the value of the vertical angle
between A and B according as one of the points is above and the other below the
horizontal plane. or both points are on the same side of the horizontal plane Fig b
& c.
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TO PROLONG A STRAIGHT LINE
44
There are three different methods to prolonging the given straight line:
1. Fore Sight Method
2. Back Sight Method
3. Double reversing Method
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TO PROLONG A STRAIGHT LINE
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1. Fore Sight Method:
• Set up the theodolite at A and level it accurately .Bisect the point b correctly.
Establish a point C in the line beyond B approximately by looking over the top of
the telescope and accurately by sighting through the telescope.
• Shift the instrument to B ,take a fore sight on C and establish a point D in line
beyond C.
• Repeat the process until the last point Z is reached.
46. THEODOLITE TRAVERSING
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TO PROLONG A STRAIGHT LINE
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2. Back Sight Method:
• Set up the instrument at B and level it accurately .
• Take a back sight on A.
• Tighten the upper and lower clamps, transit the telescope and establish a point C in
the line beyond B.
• Shift the theodolite to C ,back sight on B transit the telescope and establish a point D in
line beyond C. Repeat the process until the last point ( Z) is established.
• Now if the instrument is in adjustment, the points A,B,C,D and Z will be in one line,
which is straight but if it is not in adjustment i.e. line of collimation is not
perpendicular to the horizontal axis ,then C’, D’ and Z’ will not be in a straight line.
47. THEODOLITE TRAVERSING
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TO PROLONG A STRAIGHT LINE
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3. Double reversing Method
When the line is to be prolonged with high precision or when the instrument is in
imperfect adjustment, the process of double sighting or double reversing, is used.
• Suppose the line AB is to be prolonged to a point Z.
48. THEODOLITE TRAVERSING
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TO PROLONG A STRAIGHT LINE
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• Set up the theodolite at B and level it accurately.
• With the face of instrument left, back sight on A and clamp both the upper and lower
motions.
• Transit the telescope and set a point C1 ahead in line.
• Loosen the lower clamp ,revolve the telescope in the horizontal plane and back sight on
A .Bisect A exactly by using the lower clamp and its tangent screw. Now the face of
instrument is right.
• Transit the telescope and establish a point C2 in line.
• The exact position of the true point C must be mid-way between C1 and C2.
• Measure C1 C2 and establish a point C exactly mid-way, which lies on the true
prolongation of AB.
• Shift the instrument to C, double sight on B ,establish the point D1 and D2 and locate the
true point D as before.
• Continue the process until the last point Z is established.
49. THEODOLITE TRAVERSING
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Theodolite Traversing
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• A traverse is a series of connected lines whose lengths and directions are measured
in the field.
• The system of surveying in which the angles are measured with the help of a
theodolite, is called Theodolite surveying
Different methods of Traversing:
1. Traversing by included angles
2.Traversing by deflection angles
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Theodolite Traversing
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1. Traversing by included angles
• This method is more accurate than
the fast needle method. Traversing by the
method of included angles is the most
commonly used method.
• In this method, the magnetic bearing
of any one line is measured in the field.