INTRODUCTION
Surveying is the art of determining the relative position of different objects on the surface of the earth by measuring horizontal distance btw them, and preparing map to any suitable scale. So, in this section we only measure distances only in horizontal plane.
OBJECT OF SURVEYING
THE aim of surveying is to prepare a map to show the relative position of objects on surface of the earth.
2. Geodetic Surveying
In Plane survey the curvature of earth is not taken in to consideration. The lines joining any two points is considered as to be straight, and the triangle formed by any three points is also assumed as plane triangle. The area considered below the 250 km2.
In geodetic survey the curvature of earth is taken into consideration in order to have high degree of precision. The lines joining any two points is considered as a curved line. The triangle formed by any three points is also assumed as spherical lines. The area considered above the 250 km2.
Topographical Surveys
Cadastral Surveys
City Surveys
Engineering Surveys
(1) Control survey
(2) Hand survey
(3) Topographic survey
(4) Engineering survey
(a) Reconnaissance survey
(b) Preliminary survey
(c) Location survey
(5) Route survey
(6) Construction survey
(7) Astronomic survey
(8) Mine survey
Information about both surface and sub surfaces acquired for assessing for different type of reserve like the minerals, rocks and also folds, faults and helps in determining the type of foundation required and which soil treatment is required.
This is done for depicting the land use efficiency, irrigation intensity, surface drainage, slope profiles, x contours.
It is done to prepare detailed drawing of projects involving roads, railways, dams, water supply design, reservoirs, bridges etc.
1) Reconnaissance survey
To explore site conditions and availability of infrastructures.
2) Preliminary survey
To collect adequate data to prepare plan / map of area to be used for planning and design.
3) Location survey
To set out work on the ground for actual construction / execution of the project.
To established boundaries of properties for legal purpose for fields, estates and houses, etc.
Surveys done for military purpose, provide strategic information for deciding the future course of action.
It is done to determine the natural features of a country.
It is done to gather the information about ancient monuments, towns, villages, kingdoms.
It is carried out to locate the premises, streets water supplies sanitary systems, etc.
To establish horizontal and vertical positions of control points.
To determine the latitude, longitude (of the observation station) and azimuth (of a line through observation station) from astronomical observation.
To plan, design, and laying out of route such as highways, railways, canals, pipelines, and other linear projects.
Surveys which are required for establishment of points, lines, grades, and for staking out engineering works (after the plans have been prepared and the structural design has been done).
Chain surveying is the simplest method of surveying in which the linear measurements are directly taken in the field and the angular measurements are not taken. This type of surveying is used over small and levelled area.
Here both linear and angular measurements are made, former with made with tape or chain later with compass. This type e of survey useful for large project like dam or reservoirs.
Here elevation of different points are determined. Graduated staff and level, dumpy or automatic level is used.
In this method of surveying in which the horizontal and vertical distances of relative points are determined with the graduated staff with a transit telescope fitted with anallatic lenses.
Here observation and plotting is done simultaneously in field it is mainly used for small and medium scale mapping where great accuracy is not required.
I this surveying whole area is divided into a network of triangles to determine distances and relative positions of points spread over an area, by measuring the length of one side of each triangle and deducing its angles and length of other two sides by observation from this baseline.
EMD refers Electronic Device Measurement and in this method, distance are measured electronically using wave propagation, reflection and subsequent reception of the reflected wave.
It the combination of transit theodolite with electronic distance meter (EDM).It is also integrated with microprocessor, electronic data collector and storage system. It is used to measure sloping distance of object to the instrument, horizontal angles and vertical angles.
Data collected from total station can be downloaded into computer/laptops for further processing of information.
Here information about the land is determined by using satellite-based navigation system and GPS.
According to the first principle the whole area is first enclosed by main station and survey line. The area is then divided into a number of parts by forming well-conditioned Triangle.The purpose of this process of working is to prevent accumulation of errors during this procedure if there is any error in the measurement of any side of a triangle then it will not affect the whole work. The error can always be detected and eliminated.
Passometer- It count the number of steps automatically.
Perambulator- it is a wheel fitted with fork and handle. Wheel is graduated and shows a distance per revolution.
Angular measurement refers to magnetic bearing or horizontal angle taken by a PRISMATIC COMPASS or THEODOLITE.
OBJECT OF SURVEYING
THE aim of surveying is to prepare a map to show the relative position of objects on surface of the earth.
Primary Classification
1. Plane Surveying2. Geodetic Surveying
In Plane survey the curvature of earth is not taken in to consideration. The lines joining any two points is considered as to be straight, and the triangle formed by any three points is also assumed as plane triangle. The area considered below the 250 km2.
In geodetic survey the curvature of earth is taken into consideration in order to have high degree of precision. The lines joining any two points is considered as a curved line. The triangle formed by any three points is also assumed as spherical lines. The area considered above the 250 km2.
Secondary Classification
Classification Based on Place of Survey
LAND SURVEY
Survey being done on land. Land surveying can be sub-divided into following categories-Topographical Surveys
Cadastral Surveys
City Surveys
Engineering Surveys
HYDROGRAPHIC SURVEY
Survey of water bodies, to established shore lines, Navigation possibilities.UNDERGROUND SURVEY
Survey required for construction of tunnel, mines.AERIAL SURVEY
It is carried out by taking photographs with cameras fitted on airplanes, helicopter. This is used to make a large-scale map.Classification Based on PURPOSE or Objective of Survey
On the basis of object of survey, the classification can be as given below.(1) Control survey
(2) Hand survey
(3) Topographic survey
(4) Engineering survey
(a) Reconnaissance survey
(b) Preliminary survey
(c) Location survey
(5) Route survey
(6) Construction survey
(7) Astronomic survey
(8) Mine survey
GEOLOGICAL SURVEY
Information about both surface and sub surfaces acquired for assessing for different type of reserve like the minerals, rocks and also folds, faults and helps in determining the type of foundation required and which soil treatment is required.
GEOGRAPHICAL SURVEY
This is done for depicting the land use efficiency, irrigation intensity, surface drainage, slope profiles, x contours.
ENGINEERING SURVEY
It is done to prepare detailed drawing of projects involving roads, railways, dams, water supply design, reservoirs, bridges etc.
1) Reconnaissance survey
To explore site conditions and availability of infrastructures.
2) Preliminary survey
To collect adequate data to prepare plan / map of area to be used for planning and design.
3) Location survey
To set out work on the ground for actual construction / execution of the project.
CADRASTRAL SURVEY
To established boundaries of properties for legal purpose for fields, estates and houses, etc.
DEFENCE SURVEY
Surveys done for military purpose, provide strategic information for deciding the future course of action.
TOPOGRAPHICAL SURVEY
It is done to determine the natural features of a country.
ARCHEOLOGICAL SURVEY
It is done to gather the information about ancient monuments, towns, villages, kingdoms.
CITY SUREVY
It is carried out to locate the premises, streets water supplies sanitary systems, etc.
CONTROL SURVEYING
To establish horizontal and vertical positions of control points.
ASTRONOMIC SURVEYS
To determine the latitude, longitude (of the observation station) and azimuth (of a line through observation station) from astronomical observation.
ROUTE SURVEY
To plan, design, and laying out of route such as highways, railways, canals, pipelines, and other linear projects.
CONSTRUCTION SURVEYS
Surveys which are required for establishment of points, lines, grades, and for staking out engineering works (after the plans have been prepared and the structural design has been done).
Classification Based on INSTRUMENTS USED
CHAIN SURVEY
Chain surveying is the simplest method of surveying in which the linear measurements are directly taken in the field and the angular measurements are not taken. This type of surveying is used over small and levelled area.
TRAVERSE / COMPASS SURVEY
Here both linear and angular measurements are made, former with made with tape or chain later with compass. This type e of survey useful for large project like dam or reservoirs.
LEVELLING SURVEY
Here elevation of different points are determined. Graduated staff and level, dumpy or automatic level is used.
TACHEOMETRY
In this method of surveying in which the horizontal and vertical distances of relative points are determined with the graduated staff with a transit telescope fitted with anallatic lenses.
PLANE TABLE SURVEY
Here observation and plotting is done simultaneously in field it is mainly used for small and medium scale mapping where great accuracy is not required.
TRIANGULATION SURVEY
I this surveying whole area is divided into a network of triangles to determine distances and relative positions of points spread over an area, by measuring the length of one side of each triangle and deducing its angles and length of other two sides by observation from this baseline.
EDM SURVEY
EMD refers Electronic Device Measurement and in this method, distance are measured electronically using wave propagation, reflection and subsequent reception of the reflected wave.
TOTAL STATION SURVEY
It the combination of transit theodolite with electronic distance meter (EDM).It is also integrated with microprocessor, electronic data collector and storage system. It is used to measure sloping distance of object to the instrument, horizontal angles and vertical angles.
Data collected from total station can be downloaded into computer/laptops for further processing of information.
SATELLITE SURVEY
Here information about the land is determined by using satellite-based navigation system and GPS.
PRINCIPLE OF SURVEY
WORK FROM “WHOLE TO PART"
According to the first principle the whole area is first enclosed by main station and survey line. The area is then divided into a number of parts by forming well-conditioned Triangle.The purpose of this process of working is to prevent accumulation of errors during this procedure if there is any error in the measurement of any side of a triangle then it will not affect the whole work. The error can always be detected and eliminated.
ACCORDING TO SECOND PRINCIPLE THE NEW STATION SHOULD ALWAYS BE FIXED BY AT LEAST TWO MEASUREMENTS LINEAR OR ANGULAR FROM FIX REFERENCE POINTS.
Method of linear Measurement-
By passing or steeping- The walking step of man considered as 2.5 feet 80 cm.Passometer- It count the number of steps automatically.
Perambulator- it is a wheel fitted with fork and handle. Wheel is graduated and shows a distance per revolution.
Angular measurement refers to magnetic bearing or horizontal angle taken by a PRISMATIC COMPASS or THEODOLITE.
