The theodolite is a most accurate surveying instrument mainly used for. Therefore students are required to write the procedure according to the experiment given to them. Aug 20, 2018 6 face right when vertical circle of the theodolite is on the right of the observer. This screw should be tight whenever the theodolite is on focus on the the tripod. Pdf level survey practical cve carlington maremudze. Support centring screw it with one hand and insert and tighten the centring screw with the other. Face left and face right observations eliminate the errors due to the non from civil engi. Turn the upper slow motion tangent screw so as to make the two zeros exactly coincident. This refers to the situation when the vertical circle of the instrument. This refers to the situation when the vertical circle of the instrument is on the right of the observer when the reading is taken. The number on the bottom left is the number of degrees. Finally, in the lower window, there is a scale marked in arcminutes and. Jan 18, 2015 terms associated with measurement with theodolite face left observation while taking the reading if the verical circle is towards the left of the observer, it is called face left observation. Errors caused by not levelling a theodolite or total station carefully cannot be eliminated by taking face left and face right readings.
Pdf to experimental study for comparison theodolite and. When the vertical circle on the right of the telescope at the time of observation observations of the angles, are known as face right observation. Change face 180 degrees on both axis and log the raw vertical and horizontal angles for phase 2 now that we have the values we can do the math to verify that both the vertical and horizontal angles are within the manufactures specifications. The role of the theodolite in traversing and detail surveys is fundamental to all surveying. An illustration and procedure on repetition method is described for your. The imaginary level surface with reference to which vertical distance of the points above or below are measured, is called datum surface. Procedure for surveying the given open field closed traverse. Two values obtained with face left and two obtained with face right position of vertical circle are called one set of readings. Changing face operation of bringing the vertical circle from one side of the observer. A theodolite works by combining optical plummets or plumb bobs, a spirit bubble level, and graduated circles to find vertical and horizontal angles in surveying. In other words, transiting results in a change of face. The observation taken in face left position is known as face left observation.
The following procedure would normally be adopted to measure the horizontal angle. A theodolite is a measuring instrument used to measure the horizontal and vertical angles. This refers to the situation when the vertical circle of the instrument is on the right of. Why are face left and face right observations taken. Changing face is a procedure with which all surveyors are familiar. The instrumental errors involved in theodolite surveying are. Theodolites how does a theodolite work theodolite vs. It means that the vertical circle of the theodolite is on the left of the observation at time of taking reading. If the face of the vertical circle is to the left of the observer, the observation of the angle is known as face left observation face right. Theodolite lesson 5 horizontal angle when two lines are meeting on a horizontal plane the angular.
Theodolite surveying surveying scientific observation. Face left and face right are the terms used in optical theodolite, while direct mode and. The mean of the two measures of the angle abc on two faces is the required value of the angle abc. Horizontal and vertical angle measurement in field by. Types of theodolite, surveying and levelling edurev notes. Types of surveying on the basis of whether the curvature of the earth is taken into account or not,surveying can be divided into two main categories. Change face and make three more repetitions as described above. Permanent adjustment of a transit theodolite theodolite. Count the number of spaces between the gradation marks of the number on the bottom left and that on the top right. Terms associated with measurement with theodolite face left observation while taking the reading if the verical circle is towards the left of the observer, it is called face left observation. If more precision is required the angle may be measured repeatedly. Theodolite defaults to the landscaperight orientation for ios devices, which is apples recommended default orientation to be used in cases where only a single landscape orientation is supported. The error is removed by taking the average of face left and face right readings to any. Feb 14, 2011 this video clip explains how to measure a round of angles using face left and face right measurements when precisely surveying.
It is the operation of bringing the vertical circle to the right of the observer,if originally it is to the left, and. What is the definition of face left and face right surveying. The traditional use has been for land surveying, but they are also used extensively for building and infrastructure construction, and some specialized applications such as meteorology and rocket launching. If the total station is fitted with a compensator it will measure residual tilts of the instrument and will apply corrections to the horizontal and vertical angles for these. The swing of the instrument is defined as the direction in which the theodolite is traversed i. The internal spirit level makes sure the device is level to to the horizon. You will be using a universal theodolite, model wild t2, for these measurements. Theodolite surveying lesson 1 parts of theodolite tribrach trivet foot screw outer. Face left if the vertical circle of the instrument is on the left side of the observer while taking a reading,the position is called the face left and the observation taken on the horizontal or vertical circle in this position, is known as the face left observation. This procedure varies with the experiment given to students. The theodolite is one of the most precise surveying instruments and is suitable for. It means that the vertical circle of theodolite is on the left of the observer at the time of taking reading. Theodolite parts and its functions for measurements in surveying. Pdf land surveying using auto level, leveling staff and.
This research paper with how to facilitate and manage surveying instrument theodolite and total satiation and take more accuracy for civil works methods to accomplish modernized and cost effective urban survey with best achievable accuracy. This is the sort of target that we have fixed to the wall outside. The theodolite is used to measure horizontal and vertical angles. The average horizontal angle is then obtained by taking the average of the two angles with face left and face right. Surveyingii5th civil chapter1 name of the chapter leveling. Engineering surveying 221 be introduction until recently, transits and theodolites were the most. If, when traversing, the telescope lens moves to the left we record readings as swing left. Theodolite is a telescope mounted on horizontal and vertical protractors.
Its purpose is to measure vertical andor horizontal angles. Theodolite defaults to the landscape right orientation for ios devices, which is apples recommended default orientation to be used in cases where only a single landscape orientation is supported. What is meant by face left face right in theodolite answers. Push the tripod legs firmly into the ground and use the central fixing screw to secure. It is also called as telescope inverted or bubble down. Take average of face left and face right to get further accurate horizontal angle poq method of repetition. Face left and face right observations eliminate the errors due to the. Face left and face right observations eliminate the errors. Understanding face left and face right angles surveying. The dt5 is a highlyaccurate electronic digital theodolite. Extensions of this procedure may be used to measure multiple angles from a. Dec 25, 20 errors caused by not levelling a theodolite or total station carefully cannot be eliminated by taking face left and face right readings. May 10, 2020 types of theodolite, surveying and levelling edurev notes is made by best teachers of agricultural engineering.
Indexing vertical circle by face left, face right readings. Loosen the upper clamp and turn the upper plate until the index arrow of the vernier a coincides with the zero or 360 of the horizontal circle. It is a very important instrument in plane surveying. For the first real break through from the oldfashioned open type theodolite, we must go.
It also shows how to eliminate parallax in the optics. An optical plummet ensures the theodolite is placed as close to exactly vertical above the survey point. Anyhow a vernier theodolite measures the angles up to and accuracy of 10, 20. The terms face left and face right originally refered to which side of the telescope the vertical circle of a theodolite lay when the telescope was reversed by rotating it 180 about its tilting axis. This video clip explains how to measure a round of angles using face left and face right measurements when precisely surveying.
Land surveying using auto level, leveling staff and theodolite. Face right observation while taking readings if the vertical circle is towards the right of the observer then it is called face right observation. Theodolite surveying notes, advanced surveying notes. The telescope should be in normal position face left. Recording and analysing obtained readings using autocad and excel.
Switch on the laser plummet or, for older instruments, look through the optical plummet and turn the footscrews so that the laser dot or the optical plummet is centred on the ground point illustration, top right. It implies that the vertical hover of theodolite is on the left of the eyewitness at the season of taking perusing. Surveying civil engineering gate 2020 study material pdf is useful for students and aspirants preparing for gate 2020 on self. Theodolite surveying in hindi parts of theodolite, varnier scale. Feb 27, 2018 theodolite surveyingtheodolite surveying terms used in manipulating a transit vernier theodolite. It is the operation of changing the face of the telescope from left to right and viceversa. Btec btec advanced diploma in surveying and estimating.
Face left if the vertical circle of the instrument is on the left side of the observer while taking a reading,the position is called the face left and the observation taken on the horizontal or vertical circle in this position, is known as the. This alludes to the circumstance when the vertical hover of the instrument is on the privilege of the eyewitness when the perusing is taken. Precision depends on the type and is usually from 0. This orientation puts the camera on the top edge of the device and is the preferred orientation for device accessories that follow apple guidelines. Magnetic compass measures the angle up to as accuracy of 30. Face left if the vertical circle of the instrument is on the left side of the observer while taking a reading,the position is called the face left and the observation taken on the horizontal or vertical circle in this position, is known as the face left observation 16. Theodolite circles can be instantaneously zeroed, or initialized to any value angles can be measured with increasing values either left or right angles measured by repetition can be added to provide a total larger than 360 mistakes in reading angles are greatly reduced speed of operation is increased cost of instrument is lower 15.
May 12, 2015 two values obtained with face left and two obtained with face right position of vertical circle are called one set of readings. To minimise instrument errors, it is customary to take two readings during each angle measurement, one faceleft, the other faceright, when the telescope is gently spun about its horizontal axis and then turned transited through 180 degrees in order to change the face of the instrument. Horizontal and vertical angles are simultaneously displayed on an easytoread. Face right if the vertical circle of the instrument is on the right side of the observer while taking a reading,the position is called the face right and the observation taken on the horizontal or vertical circle in this position, is known as. If vertical circle of the instrument is on the left of the observer while taking a reading, the position is called face left and the observation taken on the. Push the tripod legs firmly into the ground and use the central fixing screw to secure the instrument on the tripod. As such, traveling results in a difference in face. The distinction between functions is which two sides are compared in the ratio.