Mapua Institute of Technology School of Civil Engineering

ELEMENTARY SURVERINGFIELD MANUAL

FIELD WORK NO. 5DETERMINATION OF PENTAGONAL AREA BY RADIAL TRAVERSING

COURSE AND SECTION: CE 120-0F / A4

SUBMITTED BY:NAME: ALEJO, Danica B.STUDENT NO.:2012107733GROUP NO.: 1DATE OF FIELD WORK: MAY 7, 2015DATE OF SUBMISSION: MAY 14, 2015

GRADESUBMITTED TO:

PROFESSOR: Engr. Bienvenido Cervantes

Instruments:

LEVELLING ROD - A graduated wooden or aluminum rod, used with alevelling instrumentto determine the difference in height between points or heights of points above adatumsurface.THEODOLITE - a surveying instrument for measuring horizontal and vertical angles, consisting of a small tripod-mounted telescope that is free to move in both the horizontal and vertical planesAlso called (in the US and Canada)transit

CHALK - It is used to mark the pavements.

50 METER TAPE- A tape meter is used for measuring longer distances. Tape meters are frequently used in sports and construction to determine long distances accurately. A tape meter is a measuring tape that is generally at least ten yards in length to over one hundred yards in length. The tape itself is made to have low stretch to increase the accuracy of long distance measurements.

PLUMB BOBS (2pcs.) - These are used in taping to permit the surveyor to hold the tape horizontal when the ground is sloping. A graduation mark on the horizontal tape can be transferred down to a point on the ground using the plumb bob string. Also, a plumb bob can be used to provide precise theodolite and total station sightings.

Procedure:A. Determination of the area of a rectilinear field by radial traversing.

1. The professor assigned the corners of the rectilinear field to be observed. Drive on each corner hubs or mark each corner with a chalk on pavement.

2. Set-up the transit at a central location where all corner points will be visible and call it point O.

3. The tape men must measure and record all radial distance of the central point from each corner of the rectilinear field in the field notes provided for in this manual.

4. Level the bubbles of the transit. Set the horizontal vernier to zero reading. Tighten the upper clamp.

5. Sight the first corner of the field and tightened the lower clamp.6. Release the upper clamp. Rotate the transit in a clockwise manner and sight the next adjacent corner of a rectilinear field.

7. Read and record the first horizontal angle of the outer vernier between the first two adjacent corners.

8. Rotate the transit to sight on the third corner of the field.

9. Read and record the next central horizontal angle of the rectilinear field.

10. Follow the same procedures until you reach the first corner.

11. The sum of the central angle after measuring a closed central angle traverse must be 360*

12. Transfer the instrument in another central point where all points of the field will also be visible and repeat exactly the same procedure for the second trial of this field work.

FINAL DATA SHEET

FIELD WORK 5FIELD WORK 9 :DETERMINATION OF PENTAGONAL AREA BY RADIAL TRAVERSING

DATE: 07 MAY 2015GROUP NO. 1TIME: 1:30PM-6:00PM LOCATION: IntramurosWEATHER: SUNNYPROFESSOR: Engr. B. Cervantes

Station OccupiedA1A2A3A4A5

Oa= 14.55a= 14.55a= 12.30a= 18.60a= 8.85

b= 17.06b= 12.30b= 15.60b= 8.55b= 16.17

Area=27.48Area= 115.07Area= 86.16Area= 65.23Area= 55.92

TOTAL AREA = 392.99 m2

Station OccupiedA1A2A3A4A5

Pa= 17.31a= 10.56a= 16.73a= 6.01a= 21.76

b= 10.56b= 16.73b= 6.01b= 21,76b= 13.26

Area= 90.53Area=62.48Area= 41.21Area= 57.76Area= 142.10

TOTAL AREA = 394.08 m2

MOST PROBABLE AREA OF A RECTILINEAR FIELD = 393.54 m2

D. COMPUTATIONS

STATION OCCUPIED:

TOTAL AREA:

MOST PROBABLE AREA:

Discussion of Results:This field work entitled, Determination of the Rectilinear Area by Radial Traversing aims to acquire the knowledge in getting the area of a rectilinear field by staking a central station; to learn how to read the horizontal angle of transit; to improve skills in the analysis of the area of right triangles and to develop the ability to lead or to follow the designated/desired task of ones party or group and to be fully responsible in the performance of the assigned task.For this field work to be possible, the group needs the following instruments: Theodolite Tape Chalk / 1-set of marking pins 2 Range poles Reading Glass

THEODOLITEItis a precision instrument for measuringanglesin the horizontal and vertical planes. Theodolites are used mainly forsurveying applications, and have been adapted for specialized purposes in fields likemeteorologyandrocket launchtechnology. A modern theodolite consists of a movable telescope mounted within two perpendicular axesthe horizontal ortrunnion axis, and the vertical axis. When the telescope is pointed at a target object, the angle of each of these axes can be measured with great precision, typically to seconds of arc.Theodolites may be eithertransitornon-transit. Transit theodolites (or just "transits") are those in which the telescope can be inverted in the vertical plane, whereas the rotation in the same plane is restricted to a semi-circle for non-transit theodolites. Some types of transit theodolites do not allow the measurement of vertical angles RANGE POLESRanging poles are used to mark areas and to set out straight lines on the field. They are also used to mark points which must be seen from a distance, in which case a flag may be attached to improve the visibility.

Ranging poles are straight round stalks, 3 to 4 cm thick and about 2 m long. They are made of wood or metal. Ranging poles can also be home made from strong straight bamboo or tree branches. Ranging poles are usually painted with alternate red-white or black-white bands. If possible, wooden ranging poles are reinforced at the bottom end by metal points.

50 METER TAPE

A tape meter is used for measuring longer distances.Tape meters are frequently used in sports and construction to determine long distances accurately. A tape meter is a measuring tape that is generally at least ten yards in length to over one hundred yards in length. The tape itself is made to have low stretch to increase the accuracy of long distance measurements.

Problems Encountered/Remedies to the Problem:

Observational errors Due to lateral refraction, haze and wind the line of sight may not be truly straight. It is therefore important to keep the line of sight 1m above ground on hot sunny days. In wind and haze no need to attempt at accurate readings. If the signal is too large it is not possible to bisect accurately, and if the signal is not plumbed vertically above the station mark, wrong direction will be observed. Therefore try and always observe directly on the station mark. If this is not possible, sight to a plumb-bob or accurately plumbed target or signal; never sight to a hand held ranging rod. Errors can arise in misreading and misbooking observations of the vernier or micrometer, so always check that the reading booked appears on the instrument. Linear measurementsErrors in linear measurement are those as systematic, and random errors. These errors in linear measurements should by corrected considering its type. Angular measurementsThere are two main sources of errors in the measurement of the traverse angle. Observational errors Due to lateral refraction, haze and wind the line of sight may not be truly straight. It is there fore important to keep the line of sight 1m above ground on hot sunny days. In wind and haze no need to attempt at accurate readings. If the signal is too large it is not possible to bisect accurately, and if the signal is not plumbed vertically above the station mark, wrong direction will be observed. Therefore try and always observe directly on the station mark. If this is not possible, sight to a plumb-bob or accurately plumbed target or signal; never sight to a hand held ranging rod. Errors can arise in mis reading and mis booking observations of the vernier or micrometer, so always check that the reading booked appears on the instrument.

Instrumental errors Error in the adjustment of the theodolite. Always observe on both faces of the theodolite when measuring horizontal and vertical angles. The theodolite must be properly leveled before observations are made. So that ensure the plate bubble remains in the same position in its tube when the theodolite is rotated through 360. Ensure that the theodolite is stable with the legs firmly planted in solid ground and that the tripod adjusting screws are properly tightened. The theodolite must be properly centered over the station mark with an optical plummet or plumbing rod. If the horizontal circle is moved between observations the reduced angles will be in error. This can occur for any of the following reasons. i) Screwing the theodolite too loosely to the tripod head.ii) Omitting to secure the movable head.iii) Omitting to clamp the lower plate.iv) Using the lower tangent screw instead of the upper tangent screw.v) Moving the orientation screw on single-axis theodolites. GROSS ERRORGross errors are usually the result of a major omission in observation procedure, for example failing to record the correct height of the target prism when measuring points with a detail pole, or mistakes over orientation. The advantage of using CAD for data capture in real time means such problems are recognized in the field as soon as an error has occurred. Otherwise they can sometimes be corrected by editing and re-processing the survey after it has been downloaded.

Traversing is the method of using lengths and directions of lines between points to determine positions of the points. Traversing is normally associated with the field work of measuring angles and distances between points on the ground. Closed traverses provide the primary method used in checking surveying field work. Traverse closure and adjustment procedures are used to distribute error in measurements. Mathematical traverses performed on a computer are used to check surveying work such as mapping and legal descriptions.

A Traverse is a succession of straight lines along or through the area to be surveyed. The directions and lengths of these lines are determined by measurements taken in the field. Purpose of a traverse A traverse is currently the most common of several possible methods for establishing a series or networkof monuments with known positions on the ground. Such monuments are referred to as horizontal control points and collectively, they comprise the horizontal control for the project.

In the past, triangulation networks have served as horizontal control for larger areas, sometimes covering several states. They have been replaced recently in many places by GPS networks. (GPS will be discussed in more detail later.) GPS and other methods capitalizing on new technology may eventually replace traversing as a primary means of establishing horizontal control. Meanwhile, most surveys covering relatively small areas will continue to rely on traverses.

Whatever method is employed to establish horizontal control, the result is to assign rectangular coordinates to each control point within the survey. This allows each point to be related to every other point with respect to distance and direction, as well as to permit areas to be calculated when needed.

What the ninth experiment usually tackles is about Radial surveying methods which can be accomplished using various equipment combinations, but they are ideally suited for the modern total station instrument connected with a data collector. Radial surveying techniques are also suited for the one-person crew using a robotic total station. Each point is identified by number in the data file, and instructions are given to the instrument in terms of commands, point numbers, and, in some cases, attributes. If collecting data for a topographic site plan, the point numbers may be assigned sequentially by default. In the layout mode, the operator specifies the points to be used or staked in any order desired. In either case (collecting data or laying out points), both the point occupied by the instrument and the backsight point must be specified by the user.Radial surveying has two primary advantages: The geometry of points to be staked may involve curves, spirals, offsets, or other complex geometrical relationships, but, in the field, the solution boils down to an angle from a known backsight and a distance from the instrument. Decisions about which point to occupy with the instrument and which point to use as a backsight can be deferred to the responsible person in the field. Intervisibility between points is essential for line-of-sight equipment, but, whether tying in points or staking locations, the logistical operations are made easier by the flexibility of the method. When performing radial stakeout, the computations are performed by computer, and details are rarely of concern to the end user. However, should it be necessary, for whatever reason, to perform the angle-right/distance computations by hand, the following procedure as illustrated in Figure 4.14 may be helpful. The conventional procedure is to perform two separate inverse computations and to use the two computed azimuths to find the appropriate angle-right. Using a trigonometric identity, the procedure can be shortened and done directly on any scientific calculator.

Conclusions:In surveying, traverse is defined as a succession of straight lines along or through the area to be surveyed. The directions and lengths of these lines are determined by measurements taken in the field. Purpose of a traverse is currently the most common of several possible methods for establishing a series or network of monuments with known positions on the ground. Whatever method is employed to establish horizontal control, the result is to assign rectangular coordinates to each control point within the survey. This allows each point to be related to every other point with respect to distance and direction, as well as to permit areas to be calculated when needed.

What the ninth experiment usually tackles is about Radial surveying methods which can be accomplished using various equipment combinations, but they are ideally suited for the modern total station instrument connected with a data collector. Radial surveying techniques are also suited for the one-person crew using a robotic total station.

In this field work we had learn another reliable technique that varies from the Azimuthal reading the side shots. Side Shots is used for the determining the dimensions of an obstruct object. Sides Shots is established by putting the reader outside the regional basis of the object. Since we are to determine the area. In the field work we used side shots to determine the certainty of the length of one side of this lot, consecutively getting all four of them. The field work also establishes the furnished and by standard of the use of the theodolite.

Radial traversing is another way of computing the bearing and distances of a given lot. It is easier than the other methods because we just need to have one station, we dont need to move the instrument in different places in computing an angle or distance of a point or line. And the error the can be committed from this method is relatively low if the gathering of the data have been done right.

Learning different methods in gathering data has a great effect on a surveyors performance. There are different shapes and sizes of lot in everywhere and it cant just be solved by using one formula and method. We should know different methods that can be used in different situations.

Research:RADIAL TRAVERSEA lot of searches for traverse and how to traverse find this blog. So far I have had a bit of a rant about what a pain traversing is and how TheoLt helps me get it right. The handful of good textbooks on this and an excellent online guide by theUS DoDeducation dept. take you though the classic measure 1st and compute after method and expect you to compute long hand.

Been there, done that (even got onepublished) but, to be honest, its a tiresome business and I now trust the whole maths game to software. I can now build a network of stations for building survey swiftly and produce all the required reports as I go along- this method has the huge advantage of letting me see the blunders as I make them and take appropriate action to keep things on the level.

So now Ill have a go at explaining how I get my traverses to work and why I do them. Ill try and answer some introductory questions and then move on to a step by step walk through of the TheoLt Pro procedures.

What is a traverse and who needs one anyway?

A traverse is a method of getting precise control points (stations) measured by TST ( Total Station Theodolite) such that they have a precisely known and distributed error. The idea is to establish a set of points with the highest precision reasonably achievable to measure the detail from. An old survey adage is always work from the whole to the part. The traverse provides control of thewholeso that measurement of thepartsis possible.

What kit do I need?Traversing is a 3 tripod game, there is no point pretending otherwise: any saving you might make on using a single pod and a hand held prism is lost in the time taken to re-do the work and the precision achievable will be compromised by the number ofrepeatedset-ups you will need to get the required backsight/foresight shots- each set-up is a source of error!

you will need: TST, 3 Tripods, 3 tribrachs, 2 prisms, 2 prism holders, 3m tape, a selection of station marks, tablet PC with AutoCAD/ Bricscad and TheoLt Pro.

You will need to be able toset upthe TST and targets over the station marks- if you cant do this swiftly and easily you are in the wrong game.

How do I start?Walk the site and consider where your stations are going to be, I have found there are 2 things above all others to remember: how am I going to mark the station? and can I see back from this point to the last and forward to the next?

Setting up over ground that will take a mark can save a huge amount of time; a simple scratch mark, a Sharpie x, a road nail in a paving joint (never try and drive one into a pave unless you want to be charged for a broken one) all work, provided you have something to mark on. If Im forced to place a station in a grassy lawn Ill see if I can find a hard detail feature to mark and work from- a peg is my least favorite mark: they MOVE!

You will need a circuit of points so a walk around the whole job is needed, spare yourself the surprise of discovering an un-crossable road or blind alley once you have begun, obvious places to work from might also be obvious places to get walked into: setting up at gates and doorways is not always the best thing to do. Trees are a pain: if you are going to return to a site in a different season you can expect your sight lines to be blocked by veg. Once you are happy you can get around the site in the minimum number of stations and mark them safely, pick one (I like to start at the back of the property its up to you) set up over your mark, set up your backsight and foresight targets. Note the heights of the 3 set ups. The disposition of instrument and targets should look like this:

Source: http://billboyheritagesurvey.wordpress.com/2012/04/17/theolt-on-the-job/

FIELD WORK PEER ASSESSMENTCOURSE: CE120-0F SECTION: A4 DATE: MAY 7, 2015FIELD WORK TITLE: DETERMINATION OF PENTAGONAL AREA BY RADIAL TRAVERSING GROUP NO. 1GROUP MEMBERS:1. Anigan, ArnieSCORE 202. Banas, Cristine JoyceSCORE 20CRITERIAExcellent4Very good3Limited2Poor112

Time ElementArrives on timeArrives within the grace period of 15 minutesLate for at most 30 minutesLate for more than 30 minutes44

PreparednessKnows what exactly is to be done in the fieldFamiliar with the procedureNeeds further explanationDoes not know what is to be done44

CooperativenessPerforms assigned task well and is willing to help group matesPerforms only assigned taskLimited in performing assigned taskDoes not want to help at all44

AccuracyComputes for the required value accurately and in such a short timeComputes for required value with little assistanceComputes the required value with some assistanceFails to compute the required value.44

Overall Contribution on fieldworkPerforms efficiently a very important task assignedPerforms the important task assignedPerforms the secondary load assignedDoes nothing44

EVALUATORS NAME/SIGNATURE: