Surveying is the art of measuring distances, angles and wide variety of surveying problems. • What is that range over a narrow but long strip of land. This manual provides basic concepts about surveying and is intended for use in This manual presents basic principles and practices of surveying for highway. the survey in which earth's curvature is neglected is called Plane surveying. Land survey: It involves measurement of various objects on land. This type of.
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BASIC SURVEYING - THEORY AND PRACTICE. Ninth Annual Seminar. Presented by the. Oregon Department of Transportation. Geometronics Unit. February. "Land surveyor" means a person who is engaged in the practice of land surveying: "Practice of land surveying" means any service of work, the adequate . Land surveying is basically an art and science of mapping and measuring land. Boundary Survey: Made to determine the length and direction of land lines.
Curves are aligned to provide smooth changes in direction in the form of deflection angles that will sum up to a certain amount by the end of the curve. The next hub to be used in a traverse is called a Foresight. The nail with the spray paint is seen using the lens on the ground and until it is visible, the theodolite is then set up to be used. The arithmetic checks must be done for all levelling calculations. It can include civil structures, such as bridges, tunnels, dams, drainage facilities such as treatment plants, pump stations with significant structural elements involved.
The knowledge of Vector analysis, equation of straight lines and calculus all combined proved to be helpful in our formula derivation. A 1 A 3 y -intercept is zero. Here we are posed with a challenge of finding c y-intercept. Since the x-intercept is known i. So that A3 is the point. This is not worth discussing.
We have no triangle and three lines lie on top of one another. It saves time for Surveyors as only one side of the field requires to be measured. The best method will definitely depend on its ease of use, stability and computational efficiency.
In this regard, land surveying being a pertinent issue in the world, an easy, stable and computationally efficient solver is imperative.
A Stroud and Dexter J. Booth A Stroud and D exter J. Thomas Calculus, 11th edition, New Delhi: Person Education. Pure Mathematics Book1, 4th edition, Longman. When this happens you can 1 protect instrument from wind by using shield, or 2 Wait until wind speed reduces.
Temperature It can cause uneven expansion of tripod and instrument parts resulting in instrument mislevelling. When this happens you can shield instrument using umbrella. Refraction Causes bending of sight line. Avoid having sight line close to objects within 0. When this cannot be done, postpone observations until better conditions exist.
When this cannot be avoided such as in marshes and swamps, pound long wooden stakes flush with surface and set tripod on stakes. Most total station instruments have sensors to suspend observations when mislevelling becomes too great.
Personal errors- Instrument not centred Can cause observed angle to be too large or small. Carefully centre and level instrument. Size of error is reduced when angles have long sight lengths.
Target not centred Can cause observed angle to be too large or small. Use long sight distances to reduce effect on observed angles. Improper use of clamps and tangent screws Practice in formation of good observing habits and familiarity with equipment will reduce these errors. Poor focusing One of the most common errors.
Be sure parallax is removed before taking observation. Avoid different operators during observation procedure. Overly careful sights This is a common beginner error. Take careful sights on targets, but do not redo procedure. Beginners tend to observe, then reobserve, then reobserve This process results in unsettling instrument and reducing pointing accuracy.
Trust your eyes. Showing the columns and reception from front top view Fig 1. I have learnt from this task on the methodology involved with setting out, how it is carried out, and what the necessary precautions which have to be taken are and at the same time the errors involved with setting out.
Uren and W. Price, a traverse is defined as a chain of straight lines which is used as a basis for the measurement of details. A traverse is produced and developed by measuring the internal angles and distances between points forming a boundary of the site. We shall be measuring close traverse in this task, where area will be found of a piece of land. Each of these straight lines is called a traverse leg and each point is called a traverse station.
Figure 2. Close Traverse Close traverse A close traverse begins and ends at the same point whose position is known. The closed traverse is mostly used for locating the boundaries at lakes, woods, or grasslands. They are mainly used for road constructions.
Fieldwork In a traverse, there are three stations which are considered to be of importance. The stations are referred to as the rear station, the occupied station and the forward station. It is the starting point.
Occupied station: This is the point which the person is measuring. Forward station: During the traverse, the horizontal angles, vertical angles and horizontal distances are measured. Fig 2. It shows the basic concept behind traversing Horizontal angles: When measuring horizontal angles, the instrument is always sighted at the lowest visible point of the station markers designated the rear and forward stations. It is done in order to avoid errors and have a more accurate drawing.
Horizontal angles are used in determining bearings. Vertical angles: Vertical angles are used in determining the difference in height between stations. The distance is very important as it helps to determine coordinates and heights. This methodology was used for traversing Selection of stations First, we measure the bench mark. From there, we take our first station reading. The stations were located in such a way that they were visible to the naked eye and visible during the measurement of the readings.
The distances were measured using the measuring tape which was 30 meters long. A taping team was set up whose job was to take the measurement between all the stations and record the measurement into a piece of paper. The line between stations was cleared of obstacles so that there is no interference. The traverse legs or stations were kept at a distance of more than 5 meters and less than 30 meters apart so that there will be less errors in azimuth and instrument centering and pointing.
Abubakar alkali kori, Ziyadah and Hasan Arbabi formed the taping team who set up all the stations and measured the distance using the measuring tape. Price Station markers Traverse stations were marked by using nails and spray paints. All the stations were marked using the letters A, B, C etc and the exact point was marked using the spray paint and nail.
Station signals Spray paint and long wooden sticks were used to mark the stations and a sketch was drawn in order to understand the area of the boundary.
A total station is defined as a device which in combination with a theodolite and an EDM together with an inboard computer or microprocessor, has the capacity to perform various computations such as determining the horizontal and vertical components of slope distances, computing elevations and coordinates of sighted points. It is set up on a tripod and a staff is used to take the measurements. The staff bubble should be accurately centered in order to obtain a highly accurate reading.
After use, all the equipment used should be carefully stored with care. Price Care of Auto Levels If the instrument becomes wet leave it unpacked. Wipe down instrument, clean and dry transport case. Pack up instrument only when it is perfectly dry. Never touch the glass with fingers, use soft clean lint-free cloth to clean lens. Place two matching level rods or two pieces of strapping in the ground about 15 meters apart with the faces toward each other.
Position and level the instrument so that the distance from the instrument to each rod is the same measure. The error needs to be corrected by a competent repair technician. In our case, parallax error was avoided by using two different group members; they moved their eyes to different parts of the eyepiece when viewing the staff held by another group member.
The height of the instrument used is 1. First, we set up the bench mark. By referring to it, we placed the tripod on the ground and opened its legs. We first placed two legs into the ground and then the third one. Each of them were equally apart from each other roughly. We placed the theodolite on top of the tripod and then centred the bubbles to obtain accurate readings. Adjust recital until crosshairs are clear.
We remove the black casing from the front lens and then switch on the theodolite. We reset it to zero.
The nail with the spray paint is seen using the lens on the ground and until it is visible, the theodolite is then set up to be used. We take the reading of the bench mark and the point 20 from behind. We then set it to zero again and take the point number 2 in front. We take the horizontal distance by using the measuring tape. Every group member was assigned a different role in order to complete the task on time and more accurately. After doing the calculations, the angles were re-aligned while maintaining the same distance due to errors.
The back bearing is defined as the angle from the south line of the same point.
My passport number is so the last two digits are The WCB is converted to radians form which is found using the formula below. The calculator is changed from degrees to radians. The arithmetic checks must be done for all levelling calculations. The HPC method of calculation can be much quicker when a lot of intermediate sights have been taken and it is a good method to use when mapping or setting out where many readings are often taken from a single instrument position.
A disadvantage of the HPC method is that the check on reduced levels calculated from IS can be long and there is a tendency for it to be omitted. Errors Instrumental - Plate level vial out of adjustment Detection: Any miscentering indicates that the plate level vial axis is not perpendicular to the vertical axis. Errors caused by peripheral equipment — Be sure that tripods, tribrach, and targets are mechanically sound and in adjustment.
Temperature Can cause uneven expansion of tripod and instrument parts resulting in instrument mislevelling. Most total station instruments have sensors to suspend observations when misleveling becomes to great.
Personal errors- Instrument miscentering Can cause observed angle to be too large or small. Target miscentering Can cause observed angle to be too large or small. Beginners tend to observe, then re observe, then re observe In our site work carried out at Lanjut Resort, I believe the collimation error was avoided to its acceptable limits since we kept sight lengths equal, especially focusing on the BS and FS. A two peg test was also carried out in order to check the collimation error.
We first placed pegs on both sides of the total station and then found the difference in elevation. Then, we moved the level 30cm past both pegs and then took the readings again. There was a slight difference in elevation from both readings and it was concluded that it is in the acceptable range. In our case, the compensator was functioning perfectly since the total station used was in good condition. In our case, parallax error was avoided by using two different group members, they moved their eyes to different parts of the eyepiece when viewing the staff held by another group member.
Another error which arises from staff defects is the zero error. It usually occurs when two staffs are used for the same series of readings, and it is advised to use only one staff for all the readings which is what we followed for our tasks. The staff is held vertically straight as well since we are measuring the vertical height of the ground. The staff was inserted into soft sand which is why there was trouble keeping the bubble on the centre for long since the sand kept the total station and the staff move a little.
To keep the accuracy in the readings, the measurement was taken quickly. To avoid this, a circle was made around the tripod and no one was allowed to enter the circle except the one using the total station. Fingertips were used to focus the total station and not the complete hand.
There were a lot of errors and mistakes in this task but it was successfully completed and such a small margin of error states that from a student of civil engineering, we are on the right verge. We worked as a team for this task and everyone was given different tasks to complete. My skills for working as a team were tested for this task. We all made new friends and got closer to each other individually then we were before.
The best part was that I learnt a lot from this task. It improved my knowledge on whole circle bearing, how to obtain mean, and how to draw a closed traverse using pen and paper and in autocad.
The autocad part was very challenging in the beginning but slowly as I managed to see some videos on You Tube and learn from the Auto Cad help section, I managed to make the drawings required for this task.
The figure is provided and the task was to produce the same figure on the beach and then measure the face right and face left and levelling measurements from stations 1, 2 and 3. The readings were then used to calculate the mean, whole circle bearing, Northing and Easting and the x and y using last two digits of the passport number.
The height of collimation method and rise and fall method were used for the levelling calculations. This report will explain the research methodology used, procedure, data, analysis of data, discussion, conclusion, recommendation and reference and appendix in the order stated. Objective The objective of carrying out this task is to carry out: The circular bubble on the upper part of the theodolite is now adjusted till it is centered by adjusting the individual tripod legs. A total station can measure both horizontal and vertical distances and at the same time the slope distances.
Using the vertical angle, the total station can calculate the horizontal and vertical distance components of the measured slope distance and display these.
The instrument is pointed towards the reflector and part of the signal returns and is processed and in a few seconds, gives the slope distances with the horizontal and vertical distances. After this, since our XY was 50, the next point was north The measurements of face right and face left were taken at every point until the whole figure was sketched out at the field using the wooden pegs and the rope was used to connect all the points.
The auto level was used to carry out the levelling measurements at every point as one group member was holding the staff. This was done using height of collimation method and rise and fall method.
The first bench mark was taken as plus last two digits of my passport number. Since my passport number is, the TBM remained as Microsoft excel was used to insert the data and do the calculations.
To make sure there are no mistakes done, the answer was checked using the following equation: The error obtained is divided by the number of stations and then the value is distributed over the stations. Rise and Fall Method For the rise and fall method, there is also an arithmetic equation provided which can show us whether the equation used is correct or not. The staff was held vertically straight as well since we are measuring the vertical height of the ground.
Price The total station. Berger Sons Correction: Axis of sight not perpendicular to horizontal axis This error cause the telescope to scribe out a cone when it is plunged.
Circle graduation errors — Caused by irregularities in marking of plates. Berger Sons Natural errors - Wind Vibrates tripod and target in windy condition. Berger Sons Tripod setting Avoid situation where legs are placed on different surfaces, and extreme soft-ground conditions.
Most total station instruments have sensors to suspend observations when misleveling becomes too great. Berger Sons Improper use of clamps and tangent screws Practice in formation of good observing habits and familiarity with equipment will reduce these errors.
The different sources of error were discussed in order to explain how surveyors encounter the different errors and the best part was that most of the errors we had experienced them at the surveying camp so it gave us a very good description and made it easy for me to explain on the errors section.
The Contour lines came out properly and they do not meet which is an essential requirement in contour drawing. The Points seem to be parallel to each other. The survey is carried out in order to establish the points required and to ensure that the road is properly produced. Now the making of a road curve involves extension of the tangent lines. You can understand the drawing properly by checking the figure below: We are carrying out the survey in order to check the health and safety issues involved with the road.
If the proper dimensions are not used, even a small margin of errors can cause accidents which can cost us human lives and damage of infrastructure and vehicles.
In other words, it can be the reason of major transportation crisis. This is why highway engineering is respected by the whole engineering society because they hold one of the most difficult jobs in the world and even a slight error is not affordable. Levelling screws use left-thumb rule.