Class Notes (808,761)
Canada (493,382)
York University (33,539)
ENG 2130 (7)
all (5)


12 Pages
Unlock Document

York University
ENG 2130

YORK UNIVERSITY Faculty of Engineering ENG 2120 / EATS 2620 FUNDAMENTALS OF SURVEYING: LAB 3 Submitted to: Mahmoud Abd El-Gelil York University, Ontario Abstract: This lab mainly focuses on finding the vertical and horizontal angles using the theodolite instrument. The lab splits into three parts. The first part was mainly on obtaining the skills for setting up the instrument using the optical plummet which is described in detail in the individual reports. The second part was testing the plate bubble and optical plummet of the instrument which is also described in the individual reports. The third part was measuring the vertical and horizontal angles using the theodolite. We set up the instrument on the tribrach at a fixed position on the floor and found four targets on the walls .Every student had to first find each of the targets on the wall and measure both the vertical and horizontal angles once forward. Then they had to flip the telescope part and take the reading at the last target again and finally take the same measurements this time backwards following the same procedure. The first student started at Zero degree angle and the following 4 students did their measurements adding 72 degrees to the angle when they were starting their data collection. The readings are fairly precise because they are being measured by very accurate instruments. Introduction: The main purpose of this lab is to introduce the instruments used in field surveying and the fundamental skills used in this field and mainly how to work with these instruments. It also focuses on skills to perform vertical and horizontal angles in the field. The instruments used in this lab are Wild T2 Optical theodolite, a tripod and four targets. The Wild T2 theodolite also known as the "universal" theodolite, is capable of coping with virtually any problem in surveying. It is mainly used to measure distances and vertical and horizontal angles.. The theodolite comes with detachable tribrach (GDF-6) that gets fastened with the instrument so that it cannot possibly fall down. The tribrach also is provided with a built-in optical plumb for levelling the instrument parallel to the floor. There are two illuminating mirrors for reading both the horizontal and vertical angles which also can cause inefficiency because they are located in two different sides. The main purpose of this lab is to introduce the Wild T2 theodolite instruments and also the vertical and horizontal angles. Objective: To obtain skills to perform the horizontal and vertical angle observations in field .Establishing surveying skills to process the multiple sets of observations to provide the final mean values. This lab also makes the students to be familiar with the new surveying instrument Wild T2 optical theodolite. Field Tasks: 1- Instrument set-up using the optical plummet 2- The instrument tests a) The plate bubble; b)The optical plummet. 3- Horizontal and vertical angle observations Field scheme: a)Identify one station and at least 4 targets around ( the distance to the individual targets should not be very different in order to avoid the refocusing errors) and plot them in a field sketch. b) Each of the group members should at least perform two full observation sets with all of the directions by applying the method of “Measurements by directions “and vertical angles as well. c) The instrument must be reset up before each of the new observation sets and use a different position of the horizontal circle. d) The field notes of the individual observation sets should have the observer’s and recorder’s names on them. Data processing: a) Perform a station adjustment to obtain the mean values of all of directions ( align the starting direction to ZERO for all of the observation sets first) and the vertical angle. Comment: Use the Wild T2 optical theodolite in this lab. 1.) Instrument Set-up Procedures Aaditya: 1) The tripod leg stabilizer was laid out on the floor above the point we intended to measure from. 2) The tripod was extended until it suited my height, and the legs guided into the ‘holes’ on the leg stabilizer. Rubber bands were stretched over the legs to secure them. 3) The Theodolite was attached onto the tripod. The circular bubble was balanced. First the bubble was aligned horizontally by twisting the two screws in opposite directions. The Theodolite was then twisted 90 . The bubble was then aligned in to the circles using the third screw. (Figure 1). 4) Once this was done, the horizontal bubble was aligned using the first two screws (Figure 2). The instrument was twisted 90 to ensure both the bubbles remained balanced. o 5) I reset the angle measure to 72 (as my base) to take measurements from. 6) The instrument was then ready to take measurements. Figure 1: Circular Bubble in centered form Figure 2: Horizontal Bubble in centered form Vincent: 1) Lay down the floor-stabilizer for the tripod over the desired set-up point. 2) Extend the tripod legs to a comfortable height, and then extend the legs to fit in the holes in the floor-stabilizer, snap legs into place, and strap the elastic over the legs. 3) Attach the theodolite to the tri-pod, by removing the cover on the centre screw in order to fasten the instrument centrally on the tripod head. 4) To centralize the circular bubble of the theodolite, the legs of the tripod are extended out or retracted until the bubble is roughly centred. 5) To further centre the bubble in the circle precisely, the rotating base of the theodolite is aligned to two level screws, and the two knobs are adjusted to decrease the bubble displacement. When the bubble is aligned for that direction, turn the theodolite 90 and then manipulate the last knob to finalize the alignment of the bubble. 6) Aligning the tubular-level-vial involves aligning the axis of the tube so that it is parallel to a pair of adjusting screws. By manipulating the adjusting knobs, centre the bubble in the vial. Turn the theodolite 180 to ensure vial remains levelled. Luke: 1) The tripod leg stabilizer was laid out on the floor at a point where the Theodolite would be equidistant from the targets 2) The legs of the tripod were fit into the holes of the leg stabilizer and rubbers bands were used to stable the tripod. 3) With the help of my group members the tripod was adjusted so that it was suited for my height 4) The Theodolite was attached to the tripod. 5) The bubble was fit into the circle by utilizing the three screws on the base of the Theodolite 6) The horizontal tangent screw was used to align the horizontal bubble in the middle Kenneth: 7) Our aim was to set the tripod leg stabilizer above the point we want to measure 8) I elevated the top portion of the tripod till it suited me at a comfortable eyelevel, and with the help of Aaditya and Vincent I placed the legs into the holes in the leg stabilizers. At the same time, we are tried to ensure that the horizontal bubble was level too. Subsequently, we secured the tripod using rubber hands to stretch over the legs. 9) I placed the theodolite onto the tripod and ensured that it was secure. In addition, the circular bubble was levelled when securing the tripod, so no further adjustments are necessary. 10)Subsequently, the horizontal bubboe was adjusted using the first two screws. I turned the theodolite about 60 to ensure that tho instrument is balanced. 11)I summarily fixed the angle to measure at 60 to commence measurements from 12)The instrument is now primed for measurements. Results Table 1: Horizontal and Vertical Measurements Name To: Direct Direct Reverse Reverse Horizontal Vertical Horizontal Vertical ° ' " ° ' " ° ' " ° ' " Atena 1 0 0 23 79 41 52 180 0 0 279 14 8
More Less

Related notes for ENG 2130

Log In


Don't have an account?

Join OneClass

Access over 10 million pages of study
documents for 1.3 million courses.

Sign up

Join to view


By registering, I agree to the Terms and Privacy Policies
Already have an account?
Just a few more details

So we can recommend you notes for your school.

Reset Password

Please enter below the email address you registered with and we will send you a link to reset your password.

Add your courses

Get notes from the top students in your class.