The document provides information on contouring and contour maps. It defines a contour as an imaginary line joining points of equal elevation. Contour maps show contour lines and provide information on surface altitudes and relative positions. The process of tracing contour lines is called contouring. Contour surveys are conducted for engineering projects to select sites, locate alignments, and minimize earthworks. The constant vertical distance between contours is the contour interval, while the horizontal distance varies based on slope. Contour interpolation involves proportionally spacing contours between plotted ground points based on assumed uniform slopes.
This document discusses contouring and contour maps. It defines a contour line as a line connecting points of equal elevation. The vertical distance between consecutive contours is called the contour interval, which depends on factors like the nature of the ground and the map scale. Contour maps show the topography of an area and can be used for engineering projects, route selection, and estimating earthworks. Methods of plotting contours include direct methods using levels or hand levels, and indirect methods like gridding, cross-sectioning, and radial lines. Characteristics of contours provide information about the landscape.
Definition of Surveying
Objects of Surveying
Uses of Surveying
Primary Divisions of Surveying
Principles of Surveying
List of Classification of Surveying
Definitions : Plan and Map, scales :Plain Scale and Diagonal Scale,
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.
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.
Indirect or reciprocal ranging is used when the ranging rod at station B is not visible from station A due to intervening ground. Two assistants are positioned at points M and N where they can be seen from both stations A and B. The surveyor at A directs the assistant at M to different positions until the line AMN is in line with station B. Then the surveyor at B directs the assistant at N to positions until the line BNM is in line with station A. This process is repeated until stations A and B are directly in line with each other.
The document provides information on plane table surveying. It describes plane table surveying as a graphical surveying method where field observations and plotting are done simultaneously. Key instruments used include a plane table mounted on a tripod, an alidade, and accessories like a trough compass and spirit level. There are different methods of plane table surveying, including radiation, intersection, and resection, which involve drawing radial lines from survey stations to locate points.
Plane table surveying involves simultaneously conducting fieldwork and plotting on a drawing board equipped with a ball and socket leveling arrangement. An alidade, which is a ruler with a fiducial edge and sighting frames, is used to draw lines of sight. A telescopic alidade can take inclined sights to increase range and accuracy. Orientation is achieved through resection or backsight methods. The radiation, intersection, traversing, and resection plane table methods are used to connect stations and fill in surveyed details on the map.
This document discusses contouring and contour maps. It defines a contour line as a line connecting points of equal elevation. The vertical distance between consecutive contours is called the contour interval, which depends on factors like the nature of the ground and the map scale. Contour maps show the topography of an area and can be used for engineering projects, route selection, and estimating earthworks. Methods of plotting contours include direct methods using levels or hand levels, and indirect methods like gridding, cross-sectioning, and radial lines. Characteristics of contours provide information about the landscape.
Definition of Surveying
Objects of Surveying
Uses of Surveying
Primary Divisions of Surveying
Principles of Surveying
List of Classification of Surveying
Definitions : Plan and Map, scales :Plain Scale and Diagonal Scale,
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.
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.
Indirect or reciprocal ranging is used when the ranging rod at station B is not visible from station A due to intervening ground. Two assistants are positioned at points M and N where they can be seen from both stations A and B. The surveyor at A directs the assistant at M to different positions until the line AMN is in line with station B. Then the surveyor at B directs the assistant at N to positions until the line BNM is in line with station A. This process is repeated until stations A and B are directly in line with each other.
The document provides information on plane table surveying. It describes plane table surveying as a graphical surveying method where field observations and plotting are done simultaneously. Key instruments used include a plane table mounted on a tripod, an alidade, and accessories like a trough compass and spirit level. There are different methods of plane table surveying, including radiation, intersection, and resection, which involve drawing radial lines from survey stations to locate points.
Plane table surveying involves simultaneously conducting fieldwork and plotting on a drawing board equipped with a ball and socket leveling arrangement. An alidade, which is a ruler with a fiducial edge and sighting frames, is used to draw lines of sight. A telescopic alidade can take inclined sights to increase range and accuracy. Orientation is achieved through resection or backsight methods. The radiation, intersection, traversing, and resection plane table methods are used to connect stations and fill in surveyed details on the map.
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.
The document discusses contouring and contour maps. It begins with definitions of key terms like contour, contour interval, and horizontal equivalent. It then describes the characteristics of contours, such as contours of equal elevation joining to indicate terrain features like hills and depressions. The methods of creating contours and their common uses are outlined, such as determining cut and fill volumes for engineering projects. Specific topics covered in the document include determining slope steepness from contour spacing, identifying ridges and valleys, and factors that determine the contour interval.
Contour lines on a topographic map represent points of equal elevation and can be used to interpret the three-dimensional shape of the land. There are direct and indirect methods for creating contour maps. The direct method traces contours on the ground while the indirect method interpolates contours between surveyed elevation points. When drawing contours, all adjacent elevation points must be considered to determine the correct path for the contour line to follow while avoiding violations of the rules governing contour characteristics. Contour maps have various uses including drawing cross sections, determining visibility between points, and planning infrastructure routes that account for terrain.
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.
Surveying is the science of determining the positions of points on or near the earth's surface. It involves decision making, fieldwork, data processing, mapping, and stakeout. The primary objectives of surveying are to prepare plans for estates, buildings, infrastructure, and to measure areas. Plane surveying considers the earth's surface flat over small areas, while geodetic surveying accounts for curvature over large areas. Distance is typically measured using tapes or chains, and errors are corrected for tape length and temperature.
Transition curve and Super-elevation
Transition Curve
Objectives of Transition Curve
Properties Of Transition Curve
Types Of Transition Curve
Length Of Transition Curve
Superelevation
Objective of providing superelevation
Advantages of providing superelevation
Superelevation Formula
Numerical
Contouring - Surveying...for civil Engineering and Architecture..Pramesh Hada
Contouring - Surveying...for civil Engineering and Architecture students. It contains all the syllabus according to Pokhara University, Nepal
---By Assistant Professor. Pramesh Hada
Nepal Engineering College
CHangunarayan, Bhaktapur
Leveling is a surveying technique used to determine differences in elevation between points. It involves measuring vertical distances between a fixed benchmark and other points using a leveling instrument, leveling rod, and trigonometric leveling. There are two main methods for leveling - the height of instrument method and rise and fall method. Leveling is used to establish elevations, construct contour maps, and determine cut/fill volumes for engineering projects.
Chapter 6 area & volume measurement, Digital PlanimeterAbhay Abhale
This document discusses the components, uses, and measurement process of a digital planimeter. It describes the main components of a digital planimeter which include a roller, tracing arm, tracing magnifier, tracing point, and function keys. It then explains the various function keys and their purposes. Finally, it outlines the step-by-step process for measuring the area of a shape using a digital planimeter, which involves selecting a scale, marking a starting point, tracing the outline while holding the tracing point, and reading the area measurement from the display.
Introduction of surveying_Surveying, Civil EngineeringA Makwana
Surveying is the art of determining the relative positions of points on, above or beneath the surface of the earth.
The relative positions are determined by measuring horizontal distances, vertical distances, horizontal angles and vertical angles accurately using various surveying instruments.
Levelling is a branch of surveying dealing with determination of relative heights of the point on the surface of the earth in a vertical plane.
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.
This document provides an overview of surveying concepts and techniques. It discusses:
1) The definitions, classifications, instruments, and methods used in surveying like chain surveying, compass surveying, plane table surveying, and total station surveying.
2) The objectives of surveying which include preparing maps, plans and transferring details to mark locations on the ground for engineering projects.
3) The primary divisions of surveying into plain surveying which ignores curvature of the earth, and geodetic surveying which accounts for curvature over large areas.
4) Fundamental surveying principles like working from the whole to parts, and locating new points using two measurements from fixed references.
This document discusses contouring and contour lines. It defines a contour line as an imaginary line connecting points of equal elevation. The vertical distance between two consecutive contours is called the contour interval, which can vary depending on factors like terrain and map scale. Contouring methods are either direct, involving determining elevations of individual points, or indirect, using calculations in the field that are less accurate but faster.
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 discusses various methods for computing the area of irregular shapes from field notes and plotted plans in surveying. It describes graphical, instrumental, and computational methods using the trapezoidal rule, mid-ordinate rule, average ordinate rule, and Simpson's rule. Specific steps are outlined for computing area from field notes by dividing the shape into triangles, rectangles, squares, and trapezoids. Methods for computing area from a plotted plan include dividing the shape into triangles using bases and altitudes, counting squares of a known unit area, or drawing parallel lines to form rectangles.
This document discusses soil mechanics concepts related to lateral earth pressure. It defines active and passive earth pressures and describes Rankine's theory and assumptions for calculating lateral pressures on retaining walls. Equations are provided for determining active and passive earth pressure coefficients and distributions for cohesionless and cohesive soils. The effects of groundwater, surcharges, and sloping backfills are also examined. Sample problems are included to calculate lateral earth pressures and forces on retaining walls for different soil and loading conditions.
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.
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.
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.
The document provides information about theodolite surveying including:
1. A theodolite is an instrument used to measure horizontal and vertical angles which can also be used to prolong lines, measure distances indirectly, and for leveling.
2. Theodolite traversing involves establishing control points by measuring angles and distances between traverse stations to calculate positions.
3. Components of a theodolite include a telescope that can rotate vertically and a compass to determine direction, along with accessories like a tripod, rods, and tapes used in surveying.
1) Contour lines on a map connect points of equal elevation and represent the topography of the land.
2) Contour surveys are conducted at the start of engineering projects to select suitable sites, locate alignments to minimize earthworks, and understand the terrain.
3) Contours are located either directly by tracing lines in the field or indirectly by taking spot levels and interpolating lines on the map. Indirect methods using cross-sections or tacheometry are more efficient for large areas.
This document discusses contour lines and contour mapping. It defines a contour line as an imaginary line connecting points of equal elevation. Contour maps show contour lines and provide information about altitudes and terrain. The process of tracing contour lines on the earth's surface is called contouring. Contour surveys are conducted for engineering projects to select suitable sites, determine earthwork volumes, and plan alignments. Common contour intervals range from 0.2-5m for detailed work to 10-25m for general topographic maps, depending on the terrain and map scale. Contours are interpolated between known elevation points using graphical or arithmetic methods.
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.
The document discusses contouring and contour maps. It begins with definitions of key terms like contour, contour interval, and horizontal equivalent. It then describes the characteristics of contours, such as contours of equal elevation joining to indicate terrain features like hills and depressions. The methods of creating contours and their common uses are outlined, such as determining cut and fill volumes for engineering projects. Specific topics covered in the document include determining slope steepness from contour spacing, identifying ridges and valleys, and factors that determine the contour interval.
Contour lines on a topographic map represent points of equal elevation and can be used to interpret the three-dimensional shape of the land. There are direct and indirect methods for creating contour maps. The direct method traces contours on the ground while the indirect method interpolates contours between surveyed elevation points. When drawing contours, all adjacent elevation points must be considered to determine the correct path for the contour line to follow while avoiding violations of the rules governing contour characteristics. Contour maps have various uses including drawing cross sections, determining visibility between points, and planning infrastructure routes that account for terrain.
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.
Surveying is the science of determining the positions of points on or near the earth's surface. It involves decision making, fieldwork, data processing, mapping, and stakeout. The primary objectives of surveying are to prepare plans for estates, buildings, infrastructure, and to measure areas. Plane surveying considers the earth's surface flat over small areas, while geodetic surveying accounts for curvature over large areas. Distance is typically measured using tapes or chains, and errors are corrected for tape length and temperature.
Transition curve and Super-elevation
Transition Curve
Objectives of Transition Curve
Properties Of Transition Curve
Types Of Transition Curve
Length Of Transition Curve
Superelevation
Objective of providing superelevation
Advantages of providing superelevation
Superelevation Formula
Numerical
Contouring - Surveying...for civil Engineering and Architecture..Pramesh Hada
Contouring - Surveying...for civil Engineering and Architecture students. It contains all the syllabus according to Pokhara University, Nepal
---By Assistant Professor. Pramesh Hada
Nepal Engineering College
CHangunarayan, Bhaktapur
Leveling is a surveying technique used to determine differences in elevation between points. It involves measuring vertical distances between a fixed benchmark and other points using a leveling instrument, leveling rod, and trigonometric leveling. There are two main methods for leveling - the height of instrument method and rise and fall method. Leveling is used to establish elevations, construct contour maps, and determine cut/fill volumes for engineering projects.
Chapter 6 area & volume measurement, Digital PlanimeterAbhay Abhale
This document discusses the components, uses, and measurement process of a digital planimeter. It describes the main components of a digital planimeter which include a roller, tracing arm, tracing magnifier, tracing point, and function keys. It then explains the various function keys and their purposes. Finally, it outlines the step-by-step process for measuring the area of a shape using a digital planimeter, which involves selecting a scale, marking a starting point, tracing the outline while holding the tracing point, and reading the area measurement from the display.
Introduction of surveying_Surveying, Civil EngineeringA Makwana
Surveying is the art of determining the relative positions of points on, above or beneath the surface of the earth.
The relative positions are determined by measuring horizontal distances, vertical distances, horizontal angles and vertical angles accurately using various surveying instruments.
Levelling is a branch of surveying dealing with determination of relative heights of the point on the surface of the earth in a vertical plane.
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.
This document provides an overview of surveying concepts and techniques. It discusses:
1) The definitions, classifications, instruments, and methods used in surveying like chain surveying, compass surveying, plane table surveying, and total station surveying.
2) The objectives of surveying which include preparing maps, plans and transferring details to mark locations on the ground for engineering projects.
3) The primary divisions of surveying into plain surveying which ignores curvature of the earth, and geodetic surveying which accounts for curvature over large areas.
4) Fundamental surveying principles like working from the whole to parts, and locating new points using two measurements from fixed references.
This document discusses contouring and contour lines. It defines a contour line as an imaginary line connecting points of equal elevation. The vertical distance between two consecutive contours is called the contour interval, which can vary depending on factors like terrain and map scale. Contouring methods are either direct, involving determining elevations of individual points, or indirect, using calculations in the field that are less accurate but faster.
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 discusses various methods for computing the area of irregular shapes from field notes and plotted plans in surveying. It describes graphical, instrumental, and computational methods using the trapezoidal rule, mid-ordinate rule, average ordinate rule, and Simpson's rule. Specific steps are outlined for computing area from field notes by dividing the shape into triangles, rectangles, squares, and trapezoids. Methods for computing area from a plotted plan include dividing the shape into triangles using bases and altitudes, counting squares of a known unit area, or drawing parallel lines to form rectangles.
This document discusses soil mechanics concepts related to lateral earth pressure. It defines active and passive earth pressures and describes Rankine's theory and assumptions for calculating lateral pressures on retaining walls. Equations are provided for determining active and passive earth pressure coefficients and distributions for cohesionless and cohesive soils. The effects of groundwater, surcharges, and sloping backfills are also examined. Sample problems are included to calculate lateral earth pressures and forces on retaining walls for different soil and loading conditions.
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.
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.
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.
The document provides information about theodolite surveying including:
1. A theodolite is an instrument used to measure horizontal and vertical angles which can also be used to prolong lines, measure distances indirectly, and for leveling.
2. Theodolite traversing involves establishing control points by measuring angles and distances between traverse stations to calculate positions.
3. Components of a theodolite include a telescope that can rotate vertically and a compass to determine direction, along with accessories like a tripod, rods, and tapes used in surveying.
1) Contour lines on a map connect points of equal elevation and represent the topography of the land.
2) Contour surveys are conducted at the start of engineering projects to select suitable sites, locate alignments to minimize earthworks, and understand the terrain.
3) Contours are located either directly by tracing lines in the field or indirectly by taking spot levels and interpolating lines on the map. Indirect methods using cross-sections or tacheometry are more efficient for large areas.
This document discusses contour lines and contour mapping. It defines a contour line as an imaginary line connecting points of equal elevation. Contour maps show contour lines and provide information about altitudes and terrain. The process of tracing contour lines on the earth's surface is called contouring. Contour surveys are conducted for engineering projects to select suitable sites, determine earthwork volumes, and plan alignments. Common contour intervals range from 0.2-5m for detailed work to 10-25m for general topographic maps, depending on the terrain and map scale. Contours are interpolated between known elevation points using graphical or arithmetic methods.
Contour lines on a map represent points of equal elevation and indicate the terrain's shape and elevation. A contour map uses contour lines to depict the landform of an area. The process of producing contour lines by determining elevation points is called contouring. Contouring can be done directly by measuring points along contour lines or indirectly by taking spot elevations and interpolating between them. The contour interval, or elevation difference between contour lines, depends on factors like terrain, map scale, and purpose of the survey. Common contour intervals range from 0.2m to 25m. Contour characteristics provide information about terrain features like hills, valleys, ridges, and slopes.
This document discusses contour mapping and surveying techniques. It contains:
1) Definitions of key terms like contour, contour line, contour map, and contour interval.
2) Descriptions of the direct and indirect methods for locating contours in the field. The direct method involves directly tracing and marking contour points, while the indirect method involves taking spot levels and interpolating the contours.
3) Characteristics used to identify topographic features like hills, depressions, ridges, and valleys from the pattern of contour lines on a map.
1. Contours are imaginary lines on a map that connect points of equal elevation. Contour maps show these lines, representing the topography of the land.
2. There are two main methods for creating contour maps - direct and indirect. The direct method involves precisely surveying points along contour lines in the field. The indirect method takes spot elevations across an area and interpolates the contour lines.
3. Common indirect techniques include surveying on a grid, along cross-sections, or using a tacheometer to measure multiple points from instrument stations. Spot elevations are plotted and contour lines drawn in between based on the terrain. The indirect method is faster but less precise than the direct method.
1. Contours are imaginary lines on a map that connect points of equal elevation. Contour maps show these lines, representing the topography of the land.
2. There are two main methods for creating contour maps - direct and indirect. The direct method involves precisely surveying points along contour lines in the field. The indirect method takes spot elevations across an area and interpolates the contour lines.
3. Common techniques for indirect contouring include dividing the area into squares and taking elevation readings at each corner, taking cross-sections of long strips, and using a tacheometer which can measure horizontal distances and elevations from a single station.
This document discusses contouring and contour maps. It defines a contour as an imaginary line joining points of equal elevation. A contour map shows these lines and provides information about altitudes and relative positions of surface features. The process of tracing contour lines is called contouring. Key terms are defined, like contour interval and horizontal equivalent. Contouring is used for site selection, canal alignment, determining ground conditions, and reservoir/earthwork capacity. Characteristics of contours are described, like indicating slopes, hills, depressions, ridges and valleys. Direct and indirect contouring methods are outlined, including spot levels, cross sections, and tacheometry.
Information About Contour And its charecteristicsAshraf Sayyed
Contour lines join points of equal elevation and are used to understand ground features and reservoir capacity. Contours are closer together on steep slopes and farther apart on gentle slopes. Lower contours inside loops indicate depressions while higher interior contours indicate ridges. Contours never cross except at cliffs. Direct and indirect contouring methods involve taking level readings and plotting points to interpolate contour lines. Direct methods contour small, controlled areas by radial lines or large oblong areas by pegs. Indirect methods use cross-sections along base lines or divide areas into squares to plot contours.
Surveying Engineering
Contour & Contouring
In this lecture we will cover
definitions.
Characteristics of contour lines.
Contours used by Engineers .
Methods of locating contour.
Method of Interpolation Contours.
Contour & Contouring
A map showing the natural and cultural features as well
as showing the nature of the surface of the land (topography of the
land) of the up and downs and its representation in (3D)three
dimensions.
A contour is a line drawn on a plan joining all points of the same
height above or below a datum.
Or A contour line
is a line that passes through points having the same elevation.
contour interval
is the constant vertical distance(VD) between any two
consecutive contours is called the contour interval
. The contour interval on this map is 20m
-The choice of suitable contour interval depends on several
factors.
-Topographic Maps
-Characteristics of contour lines.
-Contours are used by Engineers to:
-Methods of locating contour:
A- The direct methods
1- Level and staff method.
2- Plan table and alidade method.
Direct method procedure:
In this method the actual contour is pegged out on the ground and its
planimetric position located. A back-sight is taken to an appropriate BM and
the HPC of the instrument is obtained, say( 34.800m.) A staff reading of
0.800m would then place the foot of the staff at the( 34m )contour level. The
staff is then moved throughout the terrain area, with its position pegged at
every 0.800m reading. In this way the 34m contour is located. Similarly a
staff reading of (1.800m) gives the 33m contour and so on. The planimetric position of the contour needs to be located using an appropriate survey technique.
1- Grid method:-
Methods of Contouring
B- Indirect contouring
*Method of Interpolation Contours.
-Plotting contours.
Prepared by:
Asst. Prof. Salar K.Hussein
Mr. Kamal Y.Abdullah
Asst.Lecturer. Dilveen H. Omar
Erbil Polytechnic University
Technical Engineering College
Civil Engineering Department
Contour lines on a map represent imaginary lines connecting points of equal elevation. The contour interval is the vertical distance between contour lines, and depends on factors like the terrain and map scale. Contour maps depict the shape of the land through the spacing and patterns of contour lines. Closely-spaced lines indicate steep slopes, while widely-spaced lines show flatter areas. Contour maps are useful for engineering projects to determine suitable sites, locate infrastructure alignments, and estimate earthworks and reservoir capacities.
This document discusses contouring in surveying. It defines key terms like contour, contour line, and contour interval. It explains direct and indirect methods of contour surveying, including taking levels and establishing horizontal controls. It describes drawing contours and characteristics of contour maps, such as contours never intersecting except in cases of overhanging cliffs or vertical cliffs. Common contour line types are defined, like isobars and isotherms. Topographic maps and how to make a cross-section from a map are also summarized.
This document discusses contouring and contour maps. It defines a contour as an imaginary line connecting points of equal elevation. Contour maps show elevations and depressions of terrain through contour lines. The vertical distance between contours is the contour interval, while the horizontal distance is the equivalent. Contour characteristics include closer spacing on hills and wider on flats. Contours do not merge or end and indicate terrain features. Contour maps are used for engineering projects, determining drainage areas and more. Contours can be located directly by tracing or indirectly using squares, cross-sections or radiation methods.
What Exactly Is Contouring in Survey & Levelling?
It will be helpful for Architectural and Civil engineering students.
A presentation by Harshit Gupta (B.Arch 1st year).
Contour maps: preparation and understanding.VIVEK CHAUHAN
The theme behind preparation of contour maps, various projections of topographical features, the processor making them and methods used in their making.
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Contouring
1. An Edusat Lecture on
by:MOHINDER
01-02-2013
KUMAR
Sr. Lecturer Civil Engg.
Govt. Polytechnic College,
BATALA
2. Contour An imaginary line on the ground
surface joining the points of equal elevation is
known as contour.
In other words, contour is a line in which the
ground surface is intersected by a level
surface obtained by joining points of equal
elevation. This line on the map represents a
contour and is called contour line.
CONTOURING
22
3. Contour Map
A map showing contour lines is known as
Contour map.
A contour map gives an idea of the altitudes of
the surface features as well as their relative
positions in plan serves the purpose of both, a
plan and a section.
CONTOURING
3
3
4. Contouring
The process of tracing contour lines on
the surface of the earth is called
Contouring.
CONTOURING
4
3
5. PURPOSE OF CONTOURING
Contour survey is carried out at the starting of
any engineering project such as a road, a
railway, a canal, a dam, a building etc.
i) For preparing contour maps in order to select
the most economical or suitable site.
ii) To locate the alignment of a canal so that it
should follow a ridge line.
iii) To mark the alignment of roads and railways
so that the quantity of earthwork both in
cutting and filling should be minimum.
CONTOURING
5
4
6. PURPOSE OF CONTOURING (contd.)
iv) For getting information about the ground
whether it is flat, undulating or
mountainous.
v) To find the capacity of a reservoir and
volume of earthwork especially in a
mountainous region.
vi) To trace out the given grade of a particular
route.
vii)To locate the physical features of the ground
such as a pond depression, hill, steep or
small slopes.
CONTOURING
6
7. CONTOUR INTERVAL
The constant vertical distance between two
consecutive contours is called the contour
interval.
HORIZONTAL EQUIVALENT
The horizontal distance between any two
adjacent contours is called as horizontal
equivalent.
The contour interval is constant between
the consecutive contours while the horizontal
equivalent is variable and depends upon the
slope of the ground.
CONTOURING
7
8. FACTORS ON WHICH CONTOUR INTERVAL DEPENDS
The contour interval depends upon the following
factors:i) The Nature of the Ground In flat and
uniformly sloping country, the contour
interval is small , but in broken and
mountainous region the contour interval
should be large otherwise the contours will
come too close to each other.
CONTOURING
8
9. FACTORS ON WHICH CONTOUR INTERVAL DEPENDS
ii) The Purpose and extent of the survey.
Contour interval is small if the area to be
surveyed is small and the maps are required
to be used for the design work or for
determining the quantities of earth work etc.
while wider interval shall have to be kept for
large areas and comparatively less important
works.
CONTOURING
9
10. FACTORS ON WHICH CONTOUR INTERVAL DEPENDS
iii) The Scale of the Map. The contour interval
should be in the inverse ratio to the scale of
the map i.e. the smaller the scale, the greater
is the contour interval.
iv) Time and Expense of Field and Office work.
The smaller the interval, the greater is the
amount of field-work and plotting work.
CONTOURING
10
11. COMMON VALUES OF THE CONTOUR INTERVAL
The following are the common values of the
contour interval adopted for various purposes:i) For large scale maps of flat country, for
building sites, for detailed design work and
for calculation of quantities of earth work;
0.2 to 0.5 m.
CONTOURING
11
12. COMMON VALUES OF THE CONTOUR INTERVAL
ii) For reservoirs and town planning schemes;
0.5 to 2m.
iii) For location surveys.
2 to 3m.
iv) For small scale maps of broken country and
general topographic work; 3m,5m,10m,or
25m.
CONTOURING
12
13. CHARACTERISTICS OF CONTOURS
i) All points in a contour line have the same
elevation.
ii) Flat ground is indicated where the
…contours are widely separated and steepslope where they run close together.
iii) A uniform slope is indicated when the
contour lines are uniformly spaced and
iv) A plane surface when they are straight,
parallel and equally spaced.
CONTOURING
13
14. CHARACTERISTICS OF CONTOURS
v) A series of
closed contour
lines on the
map represent
a hill , if the
higher values
are inside
80
75
70
65
HILL
60
60
65
70
75
80
A HILL
15. CHARACTERISTICS OF CONTOURS
80
vi) A series of
closed contour
lines on the
map indicate a
depression if
the
higher
values
are
outside
75
70
DEPRESSION
65
60
70
60
65
70
75
80
A DEPRESSION
CONTOURING
15
16. CHARACTERISTICS OF CONTOURS
vii) Contour line cross ridge or valley line at
right angles.
100
If the higher
90
values are inside
80
the bend or loop
70
in the contour, it
60
indicates
a
50
Ridge.
RIDGE LINE
CONTOURING
16
17. CHARACTERISTICS OF CONTOURS
vii) Contour line cross ridge or valley line at
right angles.
If the higher
values are
100
outside the
90
bend,
it
80
represents
70
60
a Valley
50
VALLEY LINE
CONTOURING
17
19. CHARACTERISTICS OF CONTOURS
ix).
Contour lines cannot
merge or cross one
another
on map
except in the case of
an overhanging cliff.
40
30
20
10
40
30 20 10
OVERHANGING CLIFF
CONTOURING
19
20. CHARACTERISTICS OF CONTOURS
x) Contour lines
50
never run into one
40
another except in
30
the case of a
20
vertical cliff. In
10
this case ,several
contours coincide
and the horizontal
equivalent becomes
zero.
VERTICA
CLIFF
50
10 20 30 40 50
OVERHANGING CLIFF
CONTOURING
20
21. CHARACTERISTICS OF CONTOURS
X
Depressions
between summits is
called a saddle. It is
represented by four
SADDLE
70
sets of contours as 70
80
80
90
shown. It represents 90
90
a dip in a ridge or
100
110
the junction of two
ridges. And in the
case of a mountain Line passing through the
range ,it takes the saddles and summits gives
water shed line.
form of a pass .
CONTOURING
21
22. METHODS OF CONTOURING
There are mainly two methods of locating contours:(1)Direct Method and (2) Indirect Method.
Direct Method:
In this method, the contours to be
located are directly traced out in
the field by locating and marking
a number of points on each
contour. These points are then
surveyed and plotted on plan and
the contours drawn through
them.
CONTOURING
B.M
50
48
46
DIRECT METHOD OF
CONTOURING
22
23. METHODS OF CONTOURING
Direct Method:
•This method is most accurate but very slow
and tedious as a lot of time is wasted in
searching points of the same elevation for a
contour.
•This is suitable for small area and where great
accuracy is required
CONTOURING
23
24. Procedure: To start with, a temporary B.M is
established near the area to be surveyed with
reference to a permanent B.M by fly leveling. The
level is then set up in such a position so that the
maximum number of points can be commanded
from the instrument station. The height of
instrument is determined by taking a back sight
on the B.M. and adding it to the R.L. of bench
mark. The staff reading required to fix points on
the various contours is determined by
subtracting the R.L. of each of the contours from
the height of instrument.
CONTOURING
24
25. Example:
If the height of instrument is 82.48m.,
then the staff readings required to locate 82,
81 and 80m contours are 0.48, 1.48 and 2.48m
respectively. The staff is held on an
approximate position of point and then
moved up and down the slope until the
desired reading is obtained. The point is
marked with a peg.
CONTOURING
25
26. Example(contd.):
Similarly various other points are marked
on each contour. The line joining all these
points give the required contour. It may be
noted that one contour is located at a time.
Having fixed the contours within the range
of the instrument, the level is shifted and set
up in a new position.
CONTOURING
26
27. Procedure (Contd…..)
The new height of instrument and the
required staff readings are then calculated in a
similar manner and the process repeated till all
the contours are located. The positions of the
contour points are located suitably either
simultaneous with levelling or afterwards. A
theodolite , a compass or a plane table
traversing is usually adopted for locating these
points. The points are then plotted on the plan
and the contours drawn by joining the
corresponding points by dotted curved lines.
CONTOURING
27
28. Direct Method By Radial Lines Lines:
This method is suitable
for small areas, where a
single point in the centre
can command the whole
area. Radial lines are
laid out from the
common
centre
by
theodolite or compass
and their positions are
fixed up by horizontal
angles and bearings.
CONTOURING
70
65
60
55
Fig. RADIAL LINES
METHOD OF CONTOURING
28
29. Direct Method By Radial Lines Lines (contd.):
Temporary bench marks are first
established at the centre and near the ends of
the radial lines .The contour points are then
located and marked on these lines and their
positions are determined by measuring their
distances along the radial lines. They are then
plotted on the plan and the contours drawn by
joining all the corresponding points with the
help of a plane table instrument.
CONTOURING
29
30. 2. Indirect Method:
In this method the points located and
surveyed are not necessarily on the contour lines
but the spot levels are taken along the series of
lines laid out over the area .The spot levels of the
several representative points representing hills,
depressions, ridge and valley lines and the
changes in the slope all over the area to be
contoured are also observed. Their positions are
then plotted on the plan and the contours drawn
by interpolation. This method of contouring is
also known as contouring by spot levels.
CONTOURING
30
32. This method is commonly employed in all
kinds of surveys as this is cheaper, quicker
and less tedious as compared to direct
method. There are mainly three method of
contouring in indirect method:
(i) By Squares. In this method, the whole
area is divided into number of squares, the
side of which may vary from 5m to 30m
depending upon the nature of the ground
and the contour interval. The square need
not be of the same size throughout.
CONTOURING
31
33. 2. Indirect Method: (Square Method)
The corners of the squares are pegged out
and the reduced levels of these points are
determined with a level.
100.4
13
14
15
97.60
96.05
94.40
16
98.00
98.00
98,00
9
10
11
97.45
6
98.75
99.40
12
98.65
5
99.25
7
99.60
8
97.80
89.55
98.0
99.0
99.0
100.90
1
2
3
4
SQURES LAID ON GROUND
99.70
99.85
98.45
CONTOURS INTERPOLATED
CONTOURING
32
34. 2. Indirect Method: (Square Method)
The
important
points within the
squares may be
taken when required
and
located
by
measurements from
the corners. The
squares are plotted
and the reduced
levels of the corners
are written on the
plan.
100.4
97.60
96.05
94.40
98.00
98.00
98,00
97.45
99.25
98.65
99.60
98.75
97.80
99.40
89.55
98.0
99.0
99.0
100.90
99.70
99.85
98.45
SQUARE METHOD
CONTOURING
33
35. 2. Indirect Method:
By Cross- Sections: This method is most suitable for
the survey of long narrow strips such as a road,
railway or canal etc.
70
RD 580 70.6
RD 560 70.8
70
69.1
69
69
68.8
69.1
70.8
70.2
69.1
70.4
70.5
70.8
66.3
70.6
70.8
71
RD 540
71.2
67
68
71
69
RD 520 71.6
71.2
70.6
70
71
CONTOURING
71
72.4
71.7
Fig. X-Section Method
34
36. 2. Indirect Method:
By Cross- Sections: This method is most suitable
for the surveys of long narrow strips such as a
road, railway or canal etc. Cross sections are
run transverse to the centre line of the work and
representative points are marked along the lines
of cross-section. The cross-section lines need not
necessarily be at right angles to the centre line of
the work. This may be inclined at any angle to
the centre line if necessary. The spacing of the
cross-sections depends upon the topography of
the country and the nature of the survey.
CONTOURING
35
37. 2. Indirect Method:
By Cross- Sections:
The common value is 20 to 30 m in
hilly country and 100m in flat country. The
levels of the points along the section lines are
plotted on the plan and the contours are then
interpolated as usual as shown in the fig.
CONTOURING
36
38. 2. Indirect Method:
Fig. Stadia Wires at Diaphragm
(iii) By Tacheometric method:
A techeometer is a transit theodolite having a
diaphragm fitted with two stadia wires, one above
and other below the central wire. The horizontal
distance between the instrument and staff station
may be determined by multiplying the difference of
the staff readings of the upper and lower stadia wires
with the stadia constant of the instrument, which is
usually 100.Thus the techeometer is used for both the
vertical as well as horizontal measurements.
CONTOURING
37
39. 2. Indirect Method:
iii) By Tacheometric method (contd…):
This method is most suitable in hilly areas as the
number of stations which can be commanded by a
techeometer is far more than those by a level and thus
the number of instrument settings are considerably
reduced. A number of radial lines are laid out at a
known angular interval and representative points are
marked by pegs along these radial lines. Their
elevations and distances are then calculated and plotted
on the plan and the contour lines are then interpolated.
CONTOURING
38
40. INTERPOLATION OF CONTOURS
The process of spacing the
contours proportionally between the plotted
ground – points is termed as interpolation
of contours .
This becomes necessary in the case
of indirect contouring as only the spot
levels are taken in this method.
While interpolation of contours the ground
between any two points is assumed to be
uniformly sloping.
CONTOURING
39
41. INTERPOLATION OF CONTOURS
There are three main methods of interpolation:
i) By Estimation: The position of the contour
points between ground - points are
estimated roughly and the contours are then
drawn through these points. This is a rough
method and is suitable for small scale maps.
ii) By arithmetical calculation: This is very
tedious but accurate method and is used for
small areas where accurate results are
necessary. The contours are interpolated as
under:
CONTOURING
40
42. INTERPOLATION OF CONTOURS
ii) By arithmetical calculation:
Suppose A and B are two points at a distance
of 30 m and the reduced level of A and B are 25.45m and
27.54m respectively .Taking the contour interval as 1m,
26 and 27 m contours may be interpolated in between A
and B. The difference of level between A and B is
2.09m.the difference of level between A and 26m,and A
and 27m is 0.55mand 1.55 m respectively.
Therefore the horizontal distance between A and 26 m
contour =0.55/2.09 x 30m and
Between A and 27 m contour =1.55/2.09 x 30m.
These distances are then plotted to scale on the map.
CONTOURING
41
43. INTERPOLATION OF CONTOURS
Graphical method of (iii) By Graphical method:
interpolation
is 65
simpler as compared
B
62.5m
to
arithmetical
2
method and also the 60
60m
results obtained are
accurate. Out of
several
graphical 55
1
55m
methods, the most
common is as given
A 51.5m
below:
50
CONTOURING
42
44. Graphical method:
As shown in the fig. suppose the contour
interval is 5m, then on a piece of tracing cloth, a
number of parallel lines spaced at 0.5 m (usually
1/10th of the contour interval) are drawn. Every
tenth line being made thick.
Suppose it is required to interpolate contours
between two points A and B of elevation 51.5m
and 62.5m respectively.
CONTOURING
43
45. INTERPOLATION OF CONTOURS
(iii) By Graphical method:
If the bottom line represents an
elevation of 50m. Then the successive thick lines
will represent 55m, 60m and 65m, etc. Place the
tracing cloth so that the point A is on the third line
from the bottom, now move the tracing cloth until
B is on the fifth line above the 60m thick line. The
intersection of the thick lines 1 and 2 representing
elevations of 55m and 60 m and the line AB give
the position of the points on the 55m and 60m
contours respectively and are pricked through on
the plan with a pin.
CONTOURING
44
46. DRAWING THE CONTOUR LINES
Contour lines are drawn as fine and smooth free
hand curved lines. Sometimes they are represented by
broken lines .They are inked in either in black or brown
colour. A drawing pen gives a better line than a writing
pen and French curves should be used as much as
possible .Every fifth contour is made thicker than the
rest.
The elevation of contours must be written in a
uniform manner, either on the higher side or in a gap left
in the line .When the contour lines are very long, their
elevations are written at two or three places along the
contour .In the case of small scale maps, it is sufficient to
figure every fifth contour.
CONTOURING
45
47. USES OF CONTOUR MAP
(i) A contour map furnishes information regarding the features
of the ground , whether it is flat, undulating or mountainous.
(ii) From a contour map , sections may be easily drawn in any
direction
(iii) Intervisibility between two ground points plotted on map
can be ascertained
(iv) It enables an engineer to approximately select the most
economical or suitable site for an engineering project such as
a road, a railway, a canal or a pipe line etc.
(v) A route of a given grade can be traced on the map.
(vi) Catchment area and capacity of a reservoir may be
determined from the contour map.
(vii) Contour map may be used to determine the quantities of
earth work.
CONTOURING
45
48. HOME ASSIGNMENT
Q.No.1. (a) Define contour.
(b) What is a contour interval and on what factors does it depend?.
Q.No.2.(a) What is difference between a contour interval and horizontal
…………….equivalent?.
(b) Suggest contour intervals for following :(i) A hill Survey (ii) A city Survey (iii) survey of a dam site.
Q.No.3. Describe with neat sketches the characteristics of contours.
Q.No.4. Show contours to represent the following :(i) A Hill (ii) A Depression (iii) A valley (iv) A vertical cliff (v) A saddle.
Q.No.5. Describe various methods of interpolation of contours.
CONTOURING
46