Table of Contents
What is Surveying?
Surveying is a very necessary branch of civil engineering, the first phase to beginning a new civil engineering project. To learn the survey methods a student must research the fundamentals of it carefully. To begin learning to survey, one must begin with the definition of surveying and its significance.
Land surveying/cadastral surveying
Surveying land involves measuring and determining the boundaries of the property. All property transactions, including buying, selling, mortgaging, and leasing, are based on property boundaries. The location of property boundaries requires certainty for a secure and strong property market. Specialized training is required to locate property boundaries and knowledge of matters that may affect land ownership.
Registered land surveyors (cadastral surveyors) are the only NSW surveyors legally capable of conducting boundary surveys and representing details of property boundaries on plans or preparing subdivisions and certain types of lease plans.
Importance of surveying
- The first requirement in surveying is to create a proposal and a portion of a region that the project should protect.
- The best possible position, sum of earthwork and other required information may be determined from such planned maps and parts, depending on the complexity of the project.
- The preparation and construction of all Civil Engineering ventures such as roads, highways, bridges, drainage, lakes, reservoirs, waterworks, sewerage systems, airfields, docks, large structures, etc. are focused on surveying measurements.
- Measuring the ground and setting its borders can not be carried out without surveying.
- Throughout project execution, every magnitude is built along the lines and points defined by the survey.
- Hydrographic and oceanographic charting and visualization need application.
- The economic viability of a project’s technical design can not be adequately ascertained by carrying out survey work.
- Surveying is used to make up a topographical chart of an earth’s ground area.
Engineering surveying
In the construction and civil construction industries, engineering surveyors are generally involved. These surveyors carry out measurements and placemarks to ensure that construction works are constructed in accordance with the design plans approved. Working on construction sites, such as buildings, roads, bridges, tunnels and various other forms of infrastructure, can be found.
Mining surveying
Mining surveyors are involved in various types of mines being planned, constructed and operated. These mines can be cut open or underground. Coal, metalliferous and mineral sands are mining types. Each of these types of mining requires a skilled mining surveyor to provide specialized input. Activities of a mining surveyor can include setting out of drill patterns, excavations, and conveyors, locating underground roadways and voids, taking of measurements for volume calculations, monitoring of ground movement, land management and preparing statutory mine plans.NSW mine surveyors are registered to ensure that there is an appropriate level of competence to ensure compliance with statutory requirements and my safety.
Hydrographic surveying
The hydrographic survey involves measuring the surface of the sea, harbors and rivers, and adjacent shores. Measurements are used to prepare waterways and sea charts for use by ships and boats to ensure a safe passage and to design infrastructure in ports and harbors such as docks and jetties. Using sonar scanners they are able to provide a picture of the sea bed without needing to get their feet wet and enabling the discovery of shipwrecks and other objects lost at sea. Read More
Types of surveying
- Plane Surveying
- Geodetic or Trigonometrical Surveying
1. Plane surveying
Plane surveying deals with tiny spaces on the earth’s atmosphere considering the ground cover is plane. Therefore, the earth’s curvature is ignored. The surveying of planes may be subdivided further in the following ways:
Chain survey
The chain survey is a really old Survey process. This article contains the chain survey concept along with all the comprehensive details and required photos on various aspects of chain surveying. The easiest method of surveying is chain survey. Just samples are taken in the field in the chain study, while the majority of the analysis is performed in the lab, such as plotting estimation, etc. Only linear measurements are done here i.e. no angular measurements are made. With very few info this is best suited for tiny plane regions. This provides fairly good outcomes if handled carefully.
The required fieldwork criteria are
- Tape
- Cross staff
- Chain
- Ranging-Rod
- Arrows
The validity of chain survey
- The area to be surveyed is comparatively small
- The area is open and
- Details to be filled up are simple and less.
- The ground is fairly level
Survey Station
- Subsidiary or tie
- Main Stations
Subsidiary or tie
Subsidiary or connection stations are the points chosen on the key survey axes, where the internal information such as walls, hedges, houses, etc. need to be found.
Tie or subsidiary lines
A tie line joints two fixed points on the main survey lines. It helps to test surveying precision and to identify the specifics of the interior. The location of each connection line should be similar to other elements, such as tracks, construction, etc.
Base Lines
It is the largest and longest line running approximately down the middle of the ground. Any other measures in support of this line are taken to demonstrate the extent of the job.
Check Line
A check-line sometimes called a proof-line is a line connecting the top of a triangle on the two sides of a triangle to such fixed points. To test the consistency of the System, a cross-line is calculated. The length of a testing line would align with its position on the schedule as calculated on the field.
Offsets
Offsets are the lateral deviations from the baseline that assign the locations of the work’s different artifacts in addition to the baseline. Such offsets are usually positioned at the correct angle. Also, it can be depicted using a reel. There are 2 forms of offsets:
- Perpendicular offsets.
- Oblique offsets.
The calculations are carried out at the correct angle to the line of survey or perpendicular or correct angled offsets. One of the following approaches is used for determining perpendicular offsets:
- Swinging
- Using cross staffs
- Using optical or prism square
The chain is extended around the inspection side. The employee carries the item until the end of the film. The surveyor swings the tape on a chain line and picks the position on the chain where the minimum offset gap and records chain reading as well as offset reading on a tidy diagram of the target in a field journal. Perpendicular balances use workers at the handle.
Main Stations
Main stations are the end of the lines that order survey borders, and the lines that reach the main stations told of the central survey line or chain lines.
Field Book
Both findings and measurements taken during chain surveys should be reported in a typical book of land. It is a 200 mm / 120 mm oblong book that can be held in the back. There are two book types I single line, and (ii) double line. The pages in a single book have a red line in the center of the distance, down the length of the cover. The chain line is shown. It is distributed through both chain-ages. The room on both sides of the line is used to draw the target and to note offset distances. Within the book of the double line, there are two blue lines in the center of each book with a gap of 15 to 20 mm.
2. Traverse Surveying
Traverse Surveying is a common surveying tool. This article provides the concept of traverse surveying along with its description, traverse faults, tests completed traversing process and traverse survey plotting.
Traversing is the method of the survey in which the structure shapes a set of linked survey lines, and the directions and lengths of the survey lines are determined using an angle measuring device and tape or chain respectively.
Types of Traverse Surveying
There are two forms of surveying on the traverse. They are
Closed traverse: This is regarded as a closed traverse as the lines create a circuit that finishes at the starting point.
Open traverse: except for the starting point, when the lines of a circuit stop somewhere, it is said to be a free traverse.
The closed traverse is ideal for the position of reservoirs, forests, etc. borders and for surveying broad regions. The open track is ideal for surveying a long, narrow strip of ground, as needed by a canal or coastal route.
Methods of Traversing
There are various traverse ways, depending on the instruments used to evaluate the relative directions of the traverse axes. The key strategies are as follows:
- Chain traversing
- Chain and compass traversing
- Transit type traversing a)By fast needle method b)By measurement of angles between the lines
- Plane table traversing
Chain Traversing
The process by which the whole chain and tape function are performed is called chain traversing. No angle metric is required, so line positions are determined exclusively by linear measurements Angles are defined as chain angles, determined by linear or connection measurements. The approach is inadequate for precise research and is usually used with an angle measurement tool such as a compass.
Traversing by Fast Needle Method
The process by which traverse line magnetic bearings are determined by a theodolite equipped with s compass is called fast needle traversing. At each point, the position of the magnetic meridian is not determined but, rather, the lines ‘ magnetic bearings are calculated with a comparison such that the position of the magnetic meridian at the first point is fixed.
- The direct method with transiting,
- Direct method without transiting,
- Back bearing method.
Chain and Compass Traversing
For chain and compass traversing, a compass is used to determine the magnetic bearings of the survey lines, and the distances of the lines are then determined using a chain or a sheet. The position of the magnetic meridian is calculated separately at each traverse stop. Often recognized as a tree system or a loose needle process.
For More Details: Civil engineering
Traversing By Direct Observation of Angles
Through this process, the angles between the lines are explicitly determined by a theodolite, so it is possible to quantify the magnetic bearing on certain axes. The angles determined at numerous stations may each be
- Included Angles and
- Deflection Angles
Traverse by Deflection Angles
A deflection angle is an angle at which a sample line is rendered with the corresponding line being extended. It is known as right (R) or left (L), as determined in the clockwise or anti-clockwise direction from the previous line’s prolongation. Its method of traversing is most fitting for surveying highways, tracks, pipe-lines, etc. where the survey lines allow slight angles of deflection.
Traversing by Included Angle
A required angle at a station is one of the two angles that n\by two survey lines cross there, so both angles will be determined in a clockwise direction. The procedure is clearly to calculate each angle at the corresponding station directly from a back perspective. Also, the angled may be determined by the repeat. Depending on the location of the rear stop, the angles measured may be internal or exterior.
3. Plane Table Surveying
The surveying of plane table surveys is one of the quickest and simplest surveying techniques. In-plane table analysis, the visualization of proposals and field observations may be performed concurrently. The following scenarios are important for:
- It is often used to fill in details between stations fixed by the triangulation method or theodolite traversing method.
- It is best fitted for small-scale surveying i.e. any types of fields.
- It is also used in surveying industrial areas where the compass survey fails to perform.
Adjustments of The Plane Table
- Leveling
- Leveling is achieved so as to hold the drafting board equal to the wall. It’s achieved in the three following methods: by changing the tripod legs.
- Standard tilting of the frame by ball and bolt,
Orientation
The mechanism by which the board’s location at different survey stations is held in parallel is regarded as the orientation. The whole table has to be relocated at multiple stations in the plane table sample to complete a sample. Every time the table is shifted one needs to ensure sure the current station is identical to the previous one or the lines drawn on paper do not reflect the same lines on the ground. Orientation approaches tend to:-
- Back Spotting Guidance: This approach is a more accurate one. In this process, the new station draws a specific line drawn from the previous station again. This method is termed retrospective. We should not automatically draw the line the second time but test whether or not the current line overlaps with the previous we.
- Magnetic Needle orientation: This technique is used where the former station can not be bisected from the current station. This approach is not quite accurate owing to magnetic field fluctuations and is vulnerable to errors.
Centering
This method is intended to ensure that the point on the ground is correctly depicted in the document. It is done with the aid of plumbing fork and plumbing bob. The pointing end (at the upper hand) of the plumbing fork is held on tape, and a plumb bob is placed at the other end. The plate is manually rotated so the bob sits just over the station’s hole.
Methods of Plane Table Surveying
Intersection
Method Growing distance on the field may be calculated manually in the previous process. In the case of a steep landscape or uneven surface where lengths can not be physically measured, it is better to use the method of an intersection. The task is to:
- Two stations O1 and O2 are chosen so that they can be clearly seen from the points to be placed on display.
- In the report, the baseline (o1o2) is plotted. This is achieved in the following way: The table should be oriented and raised at station O1 and then, after orientation at station O2, the distance O1 O2 will be precisely calculated and positioned on the paper up to a certain size. The line o1o2 should be drawn on the paper to a certain size and the board will then be changed from station O1 by rear looking at station O2.
- From station O1, beams for stations A, B are drawn and so forth.
- Now moving the table to the new station and situating it again the beams of stations A, B are drawn and so forth.,
- The crossing point of beams from stations O1 and O2 will give focuses a, b and so on paper, as appeared in the figure.
Traversing Method
This is pretty much like the compass overview. It is utilized for running review lines between stations, which have been recently fixed by different techniques for study, to find the topographic subtleties.
- The plane table is fixed at an area (state A)
- From that point, a sight is taken toward B and the separation AB is estimated.
- The plane table is moved to station B and located toward A (this is gotten back to locating). Separation BA was estimated.
- The normal separation among AB and BA is plotted to an appropriate scale on the drawing paper.
- Then the point C is located from B and the separation was estimated. This procedure is rehashed for all the stations.
- Conduct some checks at uniform interims. At long last, plot the navigate lines on the drawing sheet. Notice that back locating was done uniquely for the initial two stations.
Resection Method
This strategy is reasonable for setting up new stations at a spot so as to find missing subtleties. It is the way toward deciding the recently plotted situation of any peg station, by methods for sight taken towards known focuses, the area of which has been plotted.
Resection method involves two different procedures as follows:
- The two-point problem
- The three-point problem
Two Point Problem
Right now, unmistakable focuses are chosen whose area is known and plotted on the drawing paper. The two focuses are joined and separated flawlessly. The bisecting point will be the new station.
Ordinary Leveling
- The rise of various focuses on the earth’s surface is resolved.
- Gives all the height information required for development exercises
2. Geodetic Surveying
Geodetic surveyors are engaged in very accurate readings to determine the world’s form and magnitude and monitor continent motion. Their measurements are used to monitor sea-level rise, earthquakes, and satellite tracking. Geodetic surveyors are involved in the development of coordinate systems and data used in map and plan production.
Surveying is a vitally significant civil engineering component. Specific forms of surveying also emerged based on the necessity. In order to better grasp surveying one must learn the specifics of these forms of survey.
Surveying is the practice of evaluating the relative location of various characteristics on, above or below the Earth’s surface by means of direct or indirect measurements and eventually displaying them on a sheet of paper known as a chart or diagram.
Surveying is the science and art of creating certain necessary observations to determine the relative location of the points or physical and cultural data above, on or below the Earth’s surface, and to represent them in a functional way, or to determine the direction of points or data.
Geodetic studying manages immense regions, so bend must be considered. Geodetic reviewing can be subdivided in the accompanying manners:
Triangulation
- On the land plot to be surveyed is built a network of well-defined triangles.
- Each of the lines is used as the reference, so the other lines and angles are determined accordingly.
Reciprocal Leveling
- Used to level ponds, gullies and other barriers in order to avoid instrumental mistakes.
- Rate measurements are obtained at two separate stages from two settings.
- Via this survey, the gap in rates between two obstructed locations is calculated.
Astronomical Surveying
With the aid of celestial bodies, the meridian, azimuth, latitude, longitude, etc. of the plot to be surveyed are calculated.
Photographic surveying
- Maps are constructed from images taken from relevant camera stations; the stations may also be aircraft.
- The performance is a diagram of a real-world scenario or entity, a sketch or a 3D model.
Tachometer or Stadia Surveying
- A telescopic spotting device is used to assess distances This includes an operator-controlled theodolite and a remote level staff operated by another surveyor.
- Both vertical and horizontal distances are measured the stadium readings the two horizontal markings on a theodolite.
