Unit 2
Geographical Measurement and Transportation Engineering
Q.1 Define survey? And also classify the survey?
Sol:
Surveying is the technique of determining the relative position of different features on, above, or beneath the surface of the earth by means of direct or indirect measurements and finally representing them on a sheet of paper known as a plan or map.
Classification of surveys
CLASSIFICATION OF SURVEYING
Generally, surveying is divided into two major categories: plane and geodetic surveying
- PLANE SURVEYING
PLANE SURVEYING is a process of surveying in which the portion of the earth being surveyed is considered a plane. The term is used to designate survey work in which the distances or areas involved are small enough that the curvature of the earth can be disregarded without significant error. In general, the term of limited extent. For small areas, precise results may be obtained with plane surveying methods, but the accuracy and precision of such results will decrease as the area surveyed size increases. To make computations in plane surveying, you will use formulas of plane trigonometry, algebra, and analytical geometry.
2. GEODETIC SURVEYING
GEODETIC SURVEYING is a process of surveying in which the shape and size of the earth are considered. This type of survey is suited for large areas and long lines and is used to find the precise location of basic points needed for establishing control for other surveys. In geodetic surveys, the stations are normally long distances apart, and more precise instruments and surveying methods are required for this type of surveying than for plane surveying.
3. TOPOGRAPHIC SURVEYS
The purpose of a TOPOGRAPHIC SURVEY is to gather survey data about the natural and man-made features of the land, as well as its elevations. From this information, a three-dimensional map may be prepared. You may prepare the topographic map in the office after collecting the field data or prepare it right away in the field by the plane table. The work usually consists of the following:
1. Establishing horizontal and vertical control that will serve as the framework of the survey
2. Determining enough horizontal location and elevation (usually called side shots) of ground points to provide enough data for plotting when the map is prepared
3. Locating natural and man-made features that may be required by the purpose of the survey
4. Computing distances, angles, and elevations
5. Drawing the topographic map
Topographic surveys are commonly identified with horizontal and/or vertical control of third-and lower-order accuracies.
4. ROUTE SURVEYS
The term route survey refers to surveys necessary for the location and construction of lines of transportation or communication that continue across the country for some distance, such as highways, railroads, open-conduit systems, pipelines, and power lines. Generally, the preliminary survey for this work takes the form of a topographic survey. In the final stage, the work may consist of the following:
1. Locating the centerline, usually marked by stakes at 100-ft intervals called stations
2. Determining elevations along and across the centerline for plotting profile and cross-sections
3. Plotting the profile and cross-sections and fixing the grades
4. Computing the volumes of earthwork and preparing a mass diagram
5. Staking out the extremities for cuts and fills
6. Determining drainage areas to be used in the design of ditches and culverts
7. Laying out structures, such as bridges and culvert
8. Locating right-of-way boundaries, as well as staking out fence lines, if necessary
5. SPECIAL SURVEYS
SPECIAL SURVEYS are conducted for a specific purpose and with a special type of surveying equipment and methods. A brief discussion of some of the special surveys familiar to you follows.
6. LAND SURVEYS
LAND SURVEYS (sometimes called cadastral or property surveys) are conducted to establish the exact location, boundaries, or subdivision of a tract of land in any specified area. This type of survey requires professional registration in all states. Presently, land surveys generally consist of the following chores:
1. Establishing markers or monuments to define and thereby preserve the boundaries of land belonging to a private concern, a corporation, or the government.
2. Relocating markers or monuments legally established by original surveys. This requires examining previous survey records and retracing what was done. When some markers or monuments are missing, they are re-established following recognized procedures, using whatever information is available.
3. Rerunning old land survey lines to determine their lengths and directions. As a result of the high cost of land, old lines are re-measured to get more precise measurements.
4. Subdividing landed estates into parcels of predetermined sizes and shapes.
5. Calculating areas, distances, and directions and preparing the land map to portray the survey data so that it can be used as a permanent record. 6. Writing a technical description of deeds.
7. CONTROL SURVEYS
CONTROL SURVEYS provide "basic control" or horizontal and vertical positions of points to which supplementary surveys are adjusted. These types of surveys (sometimes termed and traverse stations and the elevations of benchmarks. These control points are further used as References for hydrographic surveys of the coastal waters; for topographic control; and for the control of many states, city, and private surveys.
Horizontal and vertical controls generated by land (geodetic) surveys provide coordinated position data for all surveyors. It is, therefore, necessary that these types of surveys use first-order and second-order accuracies.
8. HYDROGRAPHIC SURVEYS
HYDROGRAPHIC SURVEYS are made to acquire data required to chart and/or map shorelines and bottom depths of streams, rivers, lakes, reservoirs, and other larger bodies of water. This type of survey is also of general importance to the navigation and development of water resources for flood control, irrigation, electrical power, and water supply.
Q.2 What are the Principles of the survey?
Sol:
The two principles are
1. LOCATION OF A POINT BY MEASUREMENT FROM TWO POINTS OF REFERENCE:
The relative positions of the points to be surveyed should be located by measuring at least two points of reference. Points of reference are points whose position is already fixed
2. THE SECOND PRINCIPLE IS TO WORK FROM WHOLE TO PART:
It is very essential to establish first a system of control points and to fix them with higher precision. Minor control points can be established by less precise methods and the details can be located using these minor control points by running minor traverses.
Q.3 Explain chain survey and its principles?
Sol:
Chain surveying
Chain surveying is that type of surveying in which only linear measurements are made in the field.
Surveying is suitable for surveys of a small extent on open ground to secure data for an exact description of the boundaries of a piece of land or to take simple details.
The principle of chain survey or Chain Triangulation, as is sometimes called, is to provide a skeleton or framework consists of a number of connected triangles, as the triangle is the only simple draw that can be plotted from the lengths of its sides measured in the field book.
To good results in plotting, the framework should be consist of triangles that are as nearly equilateral as possible.
Principle of Chain Surveying
The principle of chain surveying is triangulation. This means that the area to survey is spilled into a number of small triangles which should be well-conditioned.
In chain surveying, the side of the triangles are measured directly from the field by chain or tape, and no angular measurements are used. Here, the check lines and tie lines control the accuracy of the given work.
It is noted that plotting triangles requires no angular measurements to be made if the three sides are known.
Ranging is of two types
Direct Ranging
- The ranging in which intermediate ranging rods are placed in a straight line by direct observation from either end.
- Direct ranging is possible only when the end stations are intervisible.
Indirect Ranging
- The ranging in which intermediate points are interpolated by reciprocal ranging or running an auxiliary line.
- Indirect ranging is done where endpoints are not visible and the ground is high.
Q.4 Explain briefly the Prismatic compass?
Sol:
Compass surveying
Compass surveying is the branch of surveying in which the position of an object is located using angular measurements determined by a compass and linear measurements using a chain or tape. Compass surveying is used in the following circumstances:
If the surveying area is large, chain surveying is not adopted for surveying rather compass surveying is employed.
If the plot for surveying has numerous obstacles and undulations which prevents chaining.
If there is a time limit for surveying, compass surveying is usually adopted.
Compass surveying is not used in places that contain an iron core, power lines, etc which usually attracts magnets due to their natural properties and electromagnetic properties respectively. Compass surveying is done by using traversing. A traverse is formed by connecting the points in the plot by means of a series of straight lines.
Prismatic compass
A prismatic compass is a portable magnetic compass that can be either used as a hand instrument or can be fitted on a tripod. It contains a prism which is used for accurate measurement of readings. The greatest advantage of this compass is both sighting and reading can be done simultaneously without changing the position.
The bearings are expressed in the following two ways:
- Whole circle bearings
- Quadrantal bearings
- Whole Circle Bearings:
The horizontal angle which a line makes with the north direction of the meridian measured in the clockwise direction and can value up to 360° i.e. the whole circle, is known as whole circle bearing (W.C.B.) of the line.
The prismatic compass measures the bearings of lines in the whole circle system.
B. Quadrantal Bearings:
The horizontal angle which a line makes with the north or south direction of the meridian whichever is nearer the line measured in the clockwise or counter clockwise direction towards east or west and can value up to 90° i.e. one quadrant of a circle is known as the quadrantal bearing of the line.
The surveyor’s compass measures the bearings of lines in the quadrantal system.
Q.5 Explain the Measurement of bearing and calculation of included angles?
Sol:
Linear Measurements
The determination of the distance between two points on the surface of the earth is one of the basic operations of surveying. Measurement of horizontal distances or measuring linear measurement is required in chain surveying, traverse surveying, and other types of surveying.
Methods of making linear measurements
Direct methods
In the direct method, the distance is actually measured during fieldwork using a chain or a tape. This is the most commonly used method for linear measurements.
Optical methods
In the optical methods, principles of optics are used. The distance is not measured in the field but it is computed indirectly. The instrument used for making observations is called a tachometer.
E.D.M methods
Electronic Distance Measuring (E.D.M) instruments have been developed quite recently.
These are practically replacing the measurement of distances using chains or tapes. There is a large variety of such instruments and depending upon the precision required the instruments should be used.
Angular Measurements
There are two methods for angular measurement:
1) Triangulation Survey
2) Traverse Survey
Triangulation Survey
In the past, it was difficult to accurately measure very long distances, but it was possible to accurately measure the angles between points many kilometers apart, limited only by being able to see the distance. This could be anywhere from a few kilometers, to 50 kilometers or more. Triangulation is a surveying method that measures the angles in a triangle formed by three survey control points. Using trigonometry and the measured length of just one side, the other distances in the triangle are calculated.
Traverse Survey
Traversing is that type of survey in which a number of connected survey lines form the framework and the directions and lengths of the survey lines are measured with the help of an angle measuring instrument and a tape or chain respectively.
Q.6 Define the dumpy level, leveling, and benchmark?
Sol:
Dumpy level
The dumpy level is an optical surveying leveling instrument consisting of a telescope tube firmly secured in two collars fixed by adjusting screws to the stage by the vertical spindle. The telescope of the dumpy level can rotate only in a horizontal plane.
Leveling
The principle of equalizing backsight and foresight distances that if the level is placed exactly midway between two points and staff reading are taken to determine the difference of level, then the errors (due to inclined of collimation line, curvature, and refraction) are automatically eliminated. But in the case of a river or valley, it is not possible to set up the level midway between the two points on opposite banks. In such a case the method of reciprocal leveling is adopted, which involves reciprocal observation of both banks of the river or valley.
In reciprocal leveling, the level is set up on both banks of the river or valley and two sets of staff readings are taken by holding the staff on both banks. In this case, it is found that the errors are eliminated and the true difference of level is equal to the mean of the true apparent differences of the level.
Procedure
- Suppose A and B are two points on the opposite banks of a river. The level is set up near A and after proper temporary adjustment, staff readings are taken at A and at B.
- The level is shifted and set up very near B and after proper adjustment, staff reading is taken at A and B. Suppose the readings are a₂ and b₂ (Fig. – L.23.b).
Let h = true difference of level between A and B
e = combined error due to curvature, refraction, and collimation (The error may be positive or negative, here we assume positive
Bench Mark (B.M.)
It is a fixed reference point of known elevation with respect to datum. These are very important marks. They serve as reference points for finding the RL of new points or for conducting leveling operations in projects involving roads, railways, etc.
There are 4 kinds of benchmarks
- GTS (Great trigonometrical survey benchmark)
- Permanent benchmark
- Arbitrary benchmark
- Temporary benchmark
Q.7 Explain the determination of reduced levels by the height of the instrument method and rise and fall method?
Calculation of reduced level by Height of instrument and Rise & Fall method
Reduced level of the line of sight, RL= 0 + h1 =h1
Reduced level of point B = h1-h2
With a leveling instrument, it is possible to establish only a horizontal line, not a level line. However, for the small distances involved in ordinary leveling, the distinction between the level line and the horizontal line is negligible. The errors due to instrumental faults can be eliminated if the points are equidistant from the leveling instrument. If the point is lower, then the staff reading will be higher.
Arithmetic Check
(i) For the rise and fall method
∑B.S - ∑F.S = ∑Rise - ∑Fall = Last R.L – First R.L
(ii) Height of instrument method
∑ B.S - ∑ F.S = Last R.L – First R.L
Q.8 What are the Various modes of transportation? also, explain their merits and demerits?
Sol:
Various modes of Transportation
These most common five modes of transport are
- Railways
- Roadways
- Airways
- Waterways
- Pipelines
Advantages:
1. Less Capital Outlay:
Road transport required much less capital investment as compared to other modes of transport such as railways and air transport. The cost of constructing, operating, and maintaining roads is cheaper than that of the railways. Roads are generally constructed by the government and local authorities and only a small revenue is charged for the use of roads.
2. Door to Door Service:
The outstanding advantage of road transport is that it provides door to door or warehouse to warehouse service. This reduces cartage, loading, and unloading expenses.
3. Service in Rural Areas:
Road transport is most suited for carrying goods and people to and from rural areas which are not served by rail, water or air transport. Exchange of goods, between large towns and small villages, is made possible only through road transport.
4. Flexible Service:
Road transport has a great advantage over other modes of transport for its flexible service, its routes and timings can be adjusted and changed to individual requirements without much inconvenience.
5. Suitable for Short Distance:
It is more economical and quicker for carrying goods and people over short distances. Delays in transit of goods on account of intermediate loading and handling are avoided. Goods can be loaded directly into a road vehicle and transported straight to their place of destination.
6. Lesser Risk of Damage in Transit:
As the intermediate loading and handling are avoided, there is a lesser risk of damage, breakage, etc. of the goods in transit. Thus, road transport is most suited for transporting delicate goods like chinaware and glassware, which are likely to be damaged in the process of loading and unloading.
7. Saving in Packing Cost:
As compared to other modes of transport, the process of packing in motor transport is less complicated. Goods transported by motor transport require less packing or no packing in several cases.
8. Rapid Speed:
If the goods are to be sent immediately or quickly, motor transport is more suited than the railways or water transport. Water transport is very slow. Also, much time is wasted in booking the goods and taking delivery of the goods in case of railway and water transport.
9. Less Cost:
Road transport not only requires less initial capital investment, the cost of operation and maintenance is also comparatively less. Even if the rate charged by motor transport is a little higher than that by the railways, the actual effective cost of transporting goods by motor transport is less. The actual cost is less because the motor transport saves in packing costs and the expenses of intermediate loading, unloading, and handling charges.
10. Private Owned Vehicles:
Another advantage of road transport is that big businessmen can afford to have their own motor vehicles and initiate their own road services to market their products without causing any delay.
11. Feeder to other Modes of Transport:
The movement of goods begins and ultimately ends by making use of roads. Road and motor transport act as a feeder to the other modes of transport such as railways, ships, and airways.
Disadvantages:
Despite various merits, road/motor has some serious limitations:
1. Seasonal Nature:
Motor transport is not as reliable as rail transport. During rainy or flood season, roads become unfit and unsafe for use.
2. Accidents and Breakdowns:
There are more chances of accidents and breakdowns in case of motor transport. Thus, motor transport is not as safe as rail transport.
3. Unsuitable for Long Distance and Bulky Traffic:
This mode of transport is unsuitable and costly for transporting cheap and bulky goods over long distances.
4. Slow Speed:
The speed of motor transport is comparatively slow and limited.
5. Lack of Organization:
The road transport is comparatively less organized. More often, it is irregular and undependable. The rates charged for transportation are also unstable and unequal
Q.9 Describe the Classification of roads?
Sol:
Classification of Roads.
Classification is done on the following bases.
- According to traffic.
- According to transport tonnage
- According to importance.
- According to Location and functions.
- According to materials.
IRC CLASSIFICATION OF ROADS
1) National Highways (NH)
2) State Highways (SH)
3) Major District Roads (MDR)
4) Other District Roads (ODR)
5) Village Roads (VR)
National Highways (NH)
The National Highways Network of India is a network of highways that are managed and maintained by the Government of India. These highways measure over 70,934 km (44,076 mi) as of 2010, including over 1,000 km (620 mi) of limited access Expressways.
The National Highways Authority of India (NHAI) is the nodal agency responsible for building, upgrading, and maintaining most of the national highway network. It operates under the Ministry of Road Transport and Highways. The NHAI often uses a public-private partnership model for highway development, maintenance, and toll collection.
State Highways (SH)
The state highways are the roads that link important cities, towns, district headquarters within the state and connecting them with national highways or highways of the neighbouring states. These highways provide connections to industries/places from key areas in the state making them more accessible. The State Highways are maintained by the State Government.
Major District Roads (MDR)
These are important roads within a district connecting areas of production with markets and connecting these with each other or with the State Highways & National Highways. It also connects Taluk headquarters and rural areas to District headquarters.
Other District Roads (ODR)
Other District roads are the roads serving rural areas and providing them with an outlet to market centers, Taluk headquarters, block headquarters, or major district roads, and would serve to connect villages with a population of 1000 and above or a cluster of villages. These roads are owned by Highways Department.
Village Roads (VR)
Village roads are roads connecting villages or clusters of villages with each other to the nearest road of a higher category. These roads are under the Control of Rural Development and Panchayat Raj Department.
Unit 2
Geographical Measurement and Transportation Engineering
Q.1 Define survey? And also classify the survey?
Sol:
Surveying is the technique of determining the relative position of different features on, above, or beneath the surface of the earth by means of direct or indirect measurements and finally representing them on a sheet of paper known as a plan or map.
Classification of surveys
CLASSIFICATION OF SURVEYING
Generally, surveying is divided into two major categories: plane and geodetic surveying
- PLANE SURVEYING
PLANE SURVEYING is a process of surveying in which the portion of the earth being surveyed is considered a plane. The term is used to designate survey work in which the distances or areas involved are small enough that the curvature of the earth can be disregarded without significant error. In general, the term of limited extent. For small areas, precise results may be obtained with plane surveying methods, but the accuracy and precision of such results will decrease as the area surveyed size increases. To make computations in plane surveying, you will use formulas of plane trigonometry, algebra, and analytical geometry.
2. GEODETIC SURVEYING
GEODETIC SURVEYING is a process of surveying in which the shape and size of the earth are considered. This type of survey is suited for large areas and long lines and is used to find the precise location of basic points needed for establishing control for other surveys. In geodetic surveys, the stations are normally long distances apart, and more precise instruments and surveying methods are required for this type of surveying than for plane surveying.
3. TOPOGRAPHIC SURVEYS
The purpose of a TOPOGRAPHIC SURVEY is to gather survey data about the natural and man-made features of the land, as well as its elevations. From this information, a three-dimensional map may be prepared. You may prepare the topographic map in the office after collecting the field data or prepare it right away in the field by the plane table. The work usually consists of the following:
1. Establishing horizontal and vertical control that will serve as the framework of the survey
2. Determining enough horizontal location and elevation (usually called side shots) of ground points to provide enough data for plotting when the map is prepared
3. Locating natural and man-made features that may be required by the purpose of the survey
4. Computing distances, angles, and elevations
5. Drawing the topographic map
Topographic surveys are commonly identified with horizontal and/or vertical control of third-and lower-order accuracies.
4. ROUTE SURVEYS
The term route survey refers to surveys necessary for the location and construction of lines of transportation or communication that continue across the country for some distance, such as highways, railroads, open-conduit systems, pipelines, and power lines. Generally, the preliminary survey for this work takes the form of a topographic survey. In the final stage, the work may consist of the following:
1. Locating the centerline, usually marked by stakes at 100-ft intervals called stations
2. Determining elevations along and across the centerline for plotting profile and cross-sections
3. Plotting the profile and cross-sections and fixing the grades
4. Computing the volumes of earthwork and preparing a mass diagram
5. Staking out the extremities for cuts and fills
6. Determining drainage areas to be used in the design of ditches and culverts
7. Laying out structures, such as bridges and culvert
8. Locating right-of-way boundaries, as well as staking out fence lines, if necessary
5. SPECIAL SURVEYS
SPECIAL SURVEYS are conducted for a specific purpose and with a special type of surveying equipment and methods. A brief discussion of some of the special surveys familiar to you follows.
6. LAND SURVEYS
LAND SURVEYS (sometimes called cadastral or property surveys) are conducted to establish the exact location, boundaries, or subdivision of a tract of land in any specified area. This type of survey requires professional registration in all states. Presently, land surveys generally consist of the following chores:
1. Establishing markers or monuments to define and thereby preserve the boundaries of land belonging to a private concern, a corporation, or the government.
2. Relocating markers or monuments legally established by original surveys. This requires examining previous survey records and retracing what was done. When some markers or monuments are missing, they are re-established following recognized procedures, using whatever information is available.
3. Rerunning old land survey lines to determine their lengths and directions. As a result of the high cost of land, old lines are re-measured to get more precise measurements.
4. Subdividing landed estates into parcels of predetermined sizes and shapes.
5. Calculating areas, distances, and directions and preparing the land map to portray the survey data so that it can be used as a permanent record. 6. Writing a technical description of deeds.
7. CONTROL SURVEYS
CONTROL SURVEYS provide "basic control" or horizontal and vertical positions of points to which supplementary surveys are adjusted. These types of surveys (sometimes termed and traverse stations and the elevations of benchmarks. These control points are further used as References for hydrographic surveys of the coastal waters; for topographic control; and for the control of many states, city, and private surveys.
Horizontal and vertical controls generated by land (geodetic) surveys provide coordinated position data for all surveyors. It is, therefore, necessary that these types of surveys use first-order and second-order accuracies.
8. HYDROGRAPHIC SURVEYS
HYDROGRAPHIC SURVEYS are made to acquire data required to chart and/or map shorelines and bottom depths of streams, rivers, lakes, reservoirs, and other larger bodies of water. This type of survey is also of general importance to the navigation and development of water resources for flood control, irrigation, electrical power, and water supply.
Q.2 What are the Principles of the survey?
Sol:
The two principles are
1. LOCATION OF A POINT BY MEASUREMENT FROM TWO POINTS OF REFERENCE:
The relative positions of the points to be surveyed should be located by measuring at least two points of reference. Points of reference are points whose position is already fixed
2. THE SECOND PRINCIPLE IS TO WORK FROM WHOLE TO PART:
It is very essential to establish first a system of control points and to fix them with higher precision. Minor control points can be established by less precise methods and the details can be located using these minor control points by running minor traverses.
Q.3 Explain chain survey and its principles?
Sol:
Chain surveying
Chain surveying is that type of surveying in which only linear measurements are made in the field.
Surveying is suitable for surveys of a small extent on open ground to secure data for an exact description of the boundaries of a piece of land or to take simple details.
The principle of chain survey or Chain Triangulation, as is sometimes called, is to provide a skeleton or framework consists of a number of connected triangles, as the triangle is the only simple draw that can be plotted from the lengths of its sides measured in the field book.
To good results in plotting, the framework should be consist of triangles that are as nearly equilateral as possible.
Principle of Chain Surveying
The principle of chain surveying is triangulation. This means that the area to survey is spilled into a number of small triangles which should be well-conditioned.
In chain surveying, the side of the triangles are measured directly from the field by chain or tape, and no angular measurements are used. Here, the check lines and tie lines control the accuracy of the given work.
It is noted that plotting triangles requires no angular measurements to be made if the three sides are known.
Ranging is of two types
Direct Ranging
- The ranging in which intermediate ranging rods are placed in a straight line by direct observation from either end.
- Direct ranging is possible only when the end stations are intervisible.
Indirect Ranging
- The ranging in which intermediate points are interpolated by reciprocal ranging or running an auxiliary line.
- Indirect ranging is done where endpoints are not visible and the ground is high.
Q.4 Explain briefly the Prismatic compass?
Sol:
Compass surveying
Compass surveying is the branch of surveying in which the position of an object is located using angular measurements determined by a compass and linear measurements using a chain or tape. Compass surveying is used in the following circumstances:
If the surveying area is large, chain surveying is not adopted for surveying rather compass surveying is employed.
If the plot for surveying has numerous obstacles and undulations which prevents chaining.
If there is a time limit for surveying, compass surveying is usually adopted.
Compass surveying is not used in places that contain an iron core, power lines, etc which usually attracts magnets due to their natural properties and electromagnetic properties respectively. Compass surveying is done by using traversing. A traverse is formed by connecting the points in the plot by means of a series of straight lines.
Prismatic compass
A prismatic compass is a portable magnetic compass that can be either used as a hand instrument or can be fitted on a tripod. It contains a prism which is used for accurate measurement of readings. The greatest advantage of this compass is both sighting and reading can be done simultaneously without changing the position.
The bearings are expressed in the following two ways:
- Whole circle bearings
- Quadrantal bearings
- Whole Circle Bearings:
The horizontal angle which a line makes with the north direction of the meridian measured in the clockwise direction and can value up to 360° i.e. the whole circle, is known as whole circle bearing (W.C.B.) of the line.
The prismatic compass measures the bearings of lines in the whole circle system.
B. Quadrantal Bearings:
The horizontal angle which a line makes with the north or south direction of the meridian whichever is nearer the line measured in the clockwise or counter clockwise direction towards east or west and can value up to 90° i.e. one quadrant of a circle is known as the quadrantal bearing of the line.
The surveyor’s compass measures the bearings of lines in the quadrantal system.
Q.5 Explain the Measurement of bearing and calculation of included angles?
Sol:
Linear Measurements
The determination of the distance between two points on the surface of the earth is one of the basic operations of surveying. Measurement of horizontal distances or measuring linear measurement is required in chain surveying, traverse surveying, and other types of surveying.
Methods of making linear measurements
Direct methods
In the direct method, the distance is actually measured during fieldwork using a chain or a tape. This is the most commonly used method for linear measurements.
Optical methods
In the optical methods, principles of optics are used. The distance is not measured in the field but it is computed indirectly. The instrument used for making observations is called a tachometer.
E.D.M methods
Electronic Distance Measuring (E.D.M) instruments have been developed quite recently.
These are practically replacing the measurement of distances using chains or tapes. There is a large variety of such instruments and depending upon the precision required the instruments should be used.
Angular Measurements
There are two methods for angular measurement:
1) Triangulation Survey
2) Traverse Survey
Triangulation Survey
In the past, it was difficult to accurately measure very long distances, but it was possible to accurately measure the angles between points many kilometers apart, limited only by being able to see the distance. This could be anywhere from a few kilometers, to 50 kilometers or more. Triangulation is a surveying method that measures the angles in a triangle formed by three survey control points. Using trigonometry and the measured length of just one side, the other distances in the triangle are calculated.
Traverse Survey
Traversing is that type of survey in which a number of connected survey lines form the framework and the directions and lengths of the survey lines are measured with the help of an angle measuring instrument and a tape or chain respectively.
Q.6 Define the dumpy level, leveling, and benchmark?
Sol:
Dumpy level
The dumpy level is an optical surveying leveling instrument consisting of a telescope tube firmly secured in two collars fixed by adjusting screws to the stage by the vertical spindle. The telescope of the dumpy level can rotate only in a horizontal plane.
Leveling
The principle of equalizing backsight and foresight distances that if the level is placed exactly midway between two points and staff reading are taken to determine the difference of level, then the errors (due to inclined of collimation line, curvature, and refraction) are automatically eliminated. But in the case of a river or valley, it is not possible to set up the level midway between the two points on opposite banks. In such a case the method of reciprocal leveling is adopted, which involves reciprocal observation of both banks of the river or valley.
In reciprocal leveling, the level is set up on both banks of the river or valley and two sets of staff readings are taken by holding the staff on both banks. In this case, it is found that the errors are eliminated and the true difference of level is equal to the mean of the true apparent differences of the level.
Procedure
- Suppose A and B are two points on the opposite banks of a river. The level is set up near A and after proper temporary adjustment, staff readings are taken at A and at B.
- The level is shifted and set up very near B and after proper adjustment, staff reading is taken at A and B. Suppose the readings are a₂ and b₂ (Fig. – L.23.b).
Let h = true difference of level between A and B
e = combined error due to curvature, refraction, and collimation (The error may be positive or negative, here we assume positive
Bench Mark (B.M.)
It is a fixed reference point of known elevation with respect to datum. These are very important marks. They serve as reference points for finding the RL of new points or for conducting leveling operations in projects involving roads, railways, etc.
There are 4 kinds of benchmarks
- GTS (Great trigonometrical survey benchmark)
- Permanent benchmark
- Arbitrary benchmark
- Temporary benchmark
Q.7 Explain the determination of reduced levels by the height of the instrument method and rise and fall method?
Calculation of reduced level by Height of instrument and Rise & Fall method
Reduced level of the line of sight, RL= 0 + h1 =h1
Reduced level of point B = h1-h2
With a leveling instrument, it is possible to establish only a horizontal line, not a level line. However, for the small distances involved in ordinary leveling, the distinction between the level line and the horizontal line is negligible. The errors due to instrumental faults can be eliminated if the points are equidistant from the leveling instrument. If the point is lower, then the staff reading will be higher.
Arithmetic Check
(i) For the rise and fall method
∑B.S - ∑F.S = ∑Rise - ∑Fall = Last R.L – First R.L
(ii) Height of instrument method
∑ B.S - ∑ F.S = Last R.L – First R.L
Q.8 What are the Various modes of transportation? also, explain their merits and demerits?
Sol:
Various modes of Transportation
These most common five modes of transport are
- Railways
- Roadways
- Airways
- Waterways
- Pipelines
Advantages:
1. Less Capital Outlay:
Road transport required much less capital investment as compared to other modes of transport such as railways and air transport. The cost of constructing, operating, and maintaining roads is cheaper than that of the railways. Roads are generally constructed by the government and local authorities and only a small revenue is charged for the use of roads.
2. Door to Door Service:
The outstanding advantage of road transport is that it provides door to door or warehouse to warehouse service. This reduces cartage, loading, and unloading expenses.
3. Service in Rural Areas:
Road transport is most suited for carrying goods and people to and from rural areas which are not served by rail, water or air transport. Exchange of goods, between large towns and small villages, is made possible only through road transport.
4. Flexible Service:
Road transport has a great advantage over other modes of transport for its flexible service, its routes and timings can be adjusted and changed to individual requirements without much inconvenience.
5. Suitable for Short Distance:
It is more economical and quicker for carrying goods and people over short distances. Delays in transit of goods on account of intermediate loading and handling are avoided. Goods can be loaded directly into a road vehicle and transported straight to their place of destination.
6. Lesser Risk of Damage in Transit:
As the intermediate loading and handling are avoided, there is a lesser risk of damage, breakage, etc. of the goods in transit. Thus, road transport is most suited for transporting delicate goods like chinaware and glassware, which are likely to be damaged in the process of loading and unloading.
7. Saving in Packing Cost:
As compared to other modes of transport, the process of packing in motor transport is less complicated. Goods transported by motor transport require less packing or no packing in several cases.
8. Rapid Speed:
If the goods are to be sent immediately or quickly, motor transport is more suited than the railways or water transport. Water transport is very slow. Also, much time is wasted in booking the goods and taking delivery of the goods in case of railway and water transport.
9. Less Cost:
Road transport not only requires less initial capital investment, the cost of operation and maintenance is also comparatively less. Even if the rate charged by motor transport is a little higher than that by the railways, the actual effective cost of transporting goods by motor transport is less. The actual cost is less because the motor transport saves in packing costs and the expenses of intermediate loading, unloading, and handling charges.
10. Private Owned Vehicles:
Another advantage of road transport is that big businessmen can afford to have their own motor vehicles and initiate their own road services to market their products without causing any delay.
11. Feeder to other Modes of Transport:
The movement of goods begins and ultimately ends by making use of roads. Road and motor transport act as a feeder to the other modes of transport such as railways, ships, and airways.
Disadvantages:
Despite various merits, road/motor has some serious limitations:
1. Seasonal Nature:
Motor transport is not as reliable as rail transport. During rainy or flood season, roads become unfit and unsafe for use.
2. Accidents and Breakdowns:
There are more chances of accidents and breakdowns in case of motor transport. Thus, motor transport is not as safe as rail transport.
3. Unsuitable for Long Distance and Bulky Traffic:
This mode of transport is unsuitable and costly for transporting cheap and bulky goods over long distances.
4. Slow Speed:
The speed of motor transport is comparatively slow and limited.
5. Lack of Organization:
The road transport is comparatively less organized. More often, it is irregular and undependable. The rates charged for transportation are also unstable and unequal
Q.9 Describe the Classification of roads?
Sol:
Classification of Roads.
Classification is done on the following bases.
- According to traffic.
- According to transport tonnage
- According to importance.
- According to Location and functions.
- According to materials.
IRC CLASSIFICATION OF ROADS
1) National Highways (NH)
2) State Highways (SH)
3) Major District Roads (MDR)
4) Other District Roads (ODR)
5) Village Roads (VR)
National Highways (NH)
The National Highways Network of India is a network of highways that are managed and maintained by the Government of India. These highways measure over 70,934 km (44,076 mi) as of 2010, including over 1,000 km (620 mi) of limited access Expressways.
The National Highways Authority of India (NHAI) is the nodal agency responsible for building, upgrading, and maintaining most of the national highway network. It operates under the Ministry of Road Transport and Highways. The NHAI often uses a public-private partnership model for highway development, maintenance, and toll collection.
State Highways (SH)
The state highways are the roads that link important cities, towns, district headquarters within the state and connecting them with national highways or highways of the neighbouring states. These highways provide connections to industries/places from key areas in the state making them more accessible. The State Highways are maintained by the State Government.
Major District Roads (MDR)
These are important roads within a district connecting areas of production with markets and connecting these with each other or with the State Highways & National Highways. It also connects Taluk headquarters and rural areas to District headquarters.
Other District Roads (ODR)
Other District roads are the roads serving rural areas and providing them with an outlet to market centers, Taluk headquarters, block headquarters, or major district roads, and would serve to connect villages with a population of 1000 and above or a cluster of villages. These roads are owned by Highways Department.
Village Roads (VR)
Village roads are roads connecting villages or clusters of villages with each other to the nearest road of a higher category. These roads are under the Control of Rural Development and Panchayat Raj Department.
