Two values obtained with face left and two obtained with face right position of vertical circle are called one set of readings. 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. Horizontal and vertical angles are simultaneously displayed on an easytoread. It is the operation of changing the face of the telescope from left to right and viceversa. Count the number of spaces between the gradation marks of the number on the bottom left and that on the top right. 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. Its purpose is to measure vertical andor horizontal angles.
Permanent adjustment of a transit theodolite theodolite. This orientation puts the camera on the top edge of the device and is the preferred orientation for device accessories that follow apple guidelines. Push the tripod legs firmly into the ground and use the central fixing screw to secure the instrument on the tripod. The theodolite is a most accurate surveying instrument mainly used for. The following procedure would normally be adopted to measure the horizontal angle. Basic surveying theory and practice definition of trigonometric functions all trigonometric functions are simply ratios of one side of a right triangle to a second side of the same triangle, or one side over another side. 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 video clip explains how to measure a round of angles using face left and face right measurements when precisely surveying. 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.
If, when traversing, the telescope lens moves to the left we record readings as swing left. 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. Aug 20, 2018 6 face right when vertical circle of the theodolite is on the right of the observer. Pdf to experimental study for comparison theodolite and. 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. As such, traveling results in a difference in face. Why are face left and face right observations taken. Theodolite surveying lesson 1 parts of theodolite tribrach trivet foot screw outer. Face right observation while taking readings if the vertical circle is towards the right of the observer then it is called face right observation.
May 10, 2020 types of theodolite, surveying and levelling edurev notes is made by best teachers of agricultural engineering. Therefore students are required to write the procedure according to the experiment given to them. Precision depends on the type and is usually from 0. The theodolite is used to measure horizontal and vertical angles.
It means that the vertical circle of the theodolite is on the left of the observation at time of taking reading. Theodolite surveying in hindi parts of theodolite, varnier scale. Surveying civil engineering gate 2020 study material pdf is useful for students and aspirants preparing for gate 2020 on self. The theodolite is one of the most precise surveying instruments and is suitable for. Errors caused by not levelling a theodolite or total station carefully cannot be eliminated by taking face left and face right readings. 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. The number on the bottom left is the number of degrees. Face left and face right observations eliminate the errors due to the. This is the sort of target that we have fixed to the wall outside. The distinction between functions is which two sides are compared in the ratio. 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. 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.
You will be using a universal theodolite, model wild t2, for these measurements. The instrumental errors involved in theodolite surveying are. 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. Surveying instruments dt500 dt500s dt500a dt500as dt600 dt600s electronic digital theodolite operators manual. This procedure varies with the experiment given to students.
It is also called as telescope inverted or bubble down. Support centring screw it with one hand and insert and tighten the centring screw with the other. Theodolite surveying notes, advanced surveying notes. 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. This refers to the situation when the vertical circle of the instrument. 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. Understanding face left and face right angles surveying.
Change face and make three more repetitions as described above. The imaginary level surface with reference to which vertical distance of the points above or below are measured, is called datum surface. Anyhow a vernier theodolite measures the angles up to and accuracy of 10, 20. If more precision is required the angle may be measured repeatedly. Theodolite lesson 5 horizontal angle when two lines are meeting on a horizontal plane the angular. An illustration and procedure on repetition method is described for your. The dt5 is a highlyaccurate electronic digital theodolite. Pdf land surveying using auto level, leveling staff and. The role of the theodolite in traversing and detail surveys is fundamental to all surveying. Magnetic compass measures the angle up to as accuracy of 30. For a level, the compen sator automatically takes care of the final levelling up. 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. Face left and face right are the terms used in optical theodolite, while direct mode and.
Theodolite parts and its functions for measurements in surveying. The telescope should be in normal position face left. When this simple action of reversing, or transmitting, the theodolite telescope is made and readings are taken on both faces, the mean of the two values will be free from the small residual discrepancies that exist in all theodolites. Take average of face left and face right to get further accurate horizontal angle poq method of repetition.
Theodolites how does a theodolite work theodolite vs. For the first real break through from the oldfashioned open type theodolite, we must go. It is a very important instrument in plane surveying. The mean of the two measures of the angle abc on two faces is the required value of the angle abc. Theodolite and measurement of angles linkedin slideshare. 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 face left observation.
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. Push the tripod legs firmly into the ground and use the central fixing screw to secure. The observation taken in face left position is known as face left observation. Engineering surveying 221 be introduction until recently, transits and theodolites were the most. 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. Face left and face right observations eliminate the errors due to the non from civil engi. 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. The error is removed by taking the average of face left and face right readings to any. This screw should be tight whenever the theodolite is on focus on the the tripod. Face left and face right observations eliminate the errors. This refers to the situation when the vertical circle of the instrument is on the right of the observer when the reading is taken. Indexing vertical circle by face left, face right readings. A theodolite is a measuring instrument used to measure the horizontal and vertical angles.
Surveyingii5th civil chapter1 name of the chapter leveling. 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. 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 in the face left position, is known as the face left observation. What is meant by face left face right in theodolite answers. Changing face operation of bringing the vertical circle from one side of the observer. Feb 27, 2018 theodolite surveyingtheodolite surveying terms used in manipulating a transit vernier theodolite. It is the operation of bringing the vertical circle to the right of the observer,if originally it is to the left, and. Feb 14, 2011 this video clip explains how to measure a round of angles using face left and face right measurements when precisely surveying. What is the definition of face left and face right surveying. Pdf level survey practical cve carlington maremudze.
Types of theodolite, surveying and levelling edurev notes. The average horizontal angle is then obtained by taking the average of the two angles with face left and face right. Finally, in the lower window, there is a scale marked in arcminutes and. This refers to the situation when the vertical circle of the instrument is on the right of. This document is highly rated by agricultural engineering students and has been viewed 10140 times. Theodolite is a telescope mounted on horizontal and vertical protractors. In other words, transiting results in a change of face. Changing face is a procedure with which all surveyors are familiar. 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. 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. It means that the vertical circle of theodolite is on the left of the observer at the time of taking reading. 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. 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. The swing of the instrument is defined as the direction in which the theodolite is traversed i.
Recording and analysing obtained readings using autocad and excel. Find the average angle with face right, by dividing the final reading by three. The changing face of survey instruments changing face is a procedure with which all surveyors are familiar. 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.
Turn the upper slow motion tangent screw so as to make the two zeros exactly coincident. 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. Extensions of this procedure may be used to measure multiple angles from a. It also shows how to eliminate parallax in the optics. Procedure for surveying the given open field closed traverse. Horizontal and vertical angle measurement in field by using. Land surveying using auto level, leveling staff and theodolite. It implies that the vertical hover of theodolite is on the left of the eyewitness at the season of taking perusing. An optical plummet ensures the theodolite is placed as close to exactly vertical above the survey point. Theodolite surveying surveying scientific observation. Horizontal and vertical angle measurement in field by.
1196 536 1506 1272 1127 840 1215 634 1440 260 937 1493 564 185 744 1124 482 388 1168 1370 989 864 373 1370 1251 803 1429 305 38 619 915 1083 1078 267 1379 1072 1414 183 1315