2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLELEMENTARY SURVEYING AND MAP MAKINGSUBJECT: GEOGRAPHYCLASS: FORM THREE© Mr. Gunda W. C.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLCONCEPTS TO BE COVEREDMeaning of simple land surveyTypes of simple land surveyChain/tape surveyTypes of equipment used in chain/tape surveyingPractice chain/tape surveyingImportance of survey

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLMEANING OF SURVEY Surveying is a science of gathering, determining, recording & measuring the relative sizes of both human-made & natural features on the Earth’s surface.Surveying is the measurement of dimensional relationships, as of horizontal distances, elevations, directions, and angles, on the earth's surface especially for use in locating property boundaries, construction layout, and map-making.Surveying is the study or practice of measuring altitudes, angles, and distances on the land surface so that they can be accurately plotted on a map.Measurements involves distance, angles & heights on the Earth's surface.Results gives data which are used for making accurate plans (construction, building) & maps drawing. A land surveying professional is called a land surveyor.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLTYPES OF SURVEYThere are two main types of surveying such as Geodetic Surveying and Plane SurveyingA.GEODETIC SURVEYING (Geodes): Is a branch of surveying in which when taking measurements, the curvature of the Earth is taken into consideration.Geodetic surveys extend over large areas and lines connecting any two points on the surface of the earth are treated as arcs.For calculating their projected distances on the plans or maps, the correction for the earth’s curvature is applied to the measured distances. The angles between the curved lines are treated as spherical angles.A knowledge of spherical trigonometry is necessary for making measurements for the geodetic surveys.Geodetic surveying is carried out with the aim of knowing the Earth’s shape and size (the Earth's configuration)

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLEXAMPLE

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLB.PLANE SURVEYINGIs a branch of surveying in which measurements are taken as if the surface of the Earth is plane or flat, that is without considering the curvature of the Earth.This is called plane survey because the Earth’s surface is considered to be Plane in this kind of Survey.The line connecting any two points will be the straight line and the angles thus formed are also plane angles.Providing that a survey area covers up to 100 square miles, plane surveying is a useful survey technique.Plane surveys ignore any curvature of the Earth's surface. Lines between two points are straight lines and all angles are plane angles. Plane surveys are economical and are suitable for most major construction projects, like highways, bridges and factories.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLEXAMPLE

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOL=>> apart from those two types of surveying, there are other types of surveying that overlap with geodetic surveying and plane surveying [Can be either geodetic or plane surveying depending on whether the curvature of the earth' surface is considered or not ]; these includes :-1.TOPOGRAPHICAL SURVEYING Deals with measurements of physical features of the Earth's surface , either natural or human-made features.This kind of survey is carried out for the purpose of preparing topographical maps, constructing topographic (cross-sectional) profiles and for establishing vertical and horizontal control for accurately defining locations.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLEXAMPLE

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOL2.CADASTRAL SURVEYINGIt deals with measurements of boundaries.Is a branch of the surveying profession that is concerned with land management, and more specifically with issues of land ownership, measurement and delineation of property boundaries.Is the sub-field of surveying that specializes in the establishment and re-establishment of real property boundaries. This kind of survey is conducted with the aim of preparing a legal document such as house plans, town or city boundaries, etc. It is mainly used for ownership purposes.Example: Boundaries of Towns, Villages, Districts, Regions or even Countries.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLEXAMPLE

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOL3.ENGINEERING SURVEYINGIs undertaken to provide special information for construction projects.Is conducted for the building and construction layout of railways, bridges and roads.It is a large scale surveying that supplies details for particular engineering schemes.Example: Architecture and Civil Engineering activities needs engineering surveying.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLIMPORTANCE OF LAND SURVEYINGLand surveying is important for both social & economical activities; where its measurements taken can be used for :- Making of plans : Example Town planning, Civil engineering, Structural engineering, Architecture & Construction of building. Making /Drawing maps for various purposes: Example maps of geographical, geological & military uses.Finding of relative position & sizes of features on the land surface. Guiding travelers, geologists, engineers, military forces, census enumerators & researchers.Adding of details to existing plans on large-scale maps. Eliminating issues that arise because of land boundaries (Example: Land conflicts and disputes)

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLMETHODS OF LAND SURVEYland (geographical) surveying involves the use of the various methods such that Chain/tape surveying methodPrismatic compass surveying methodPlane-table surveying methodLeveling surveying methodCHAIN/TAPE SURVEYING METHOD Is a method of surveying that uses only linear measurements in which no angles are measured.It is a method of Surveying in which no angles are measured but only linear measurement is taken in the field by using a chain or tape measure.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLChain survey is the simplest method of surveying where only its measurements are taken in the field, and the rest work, such as plotting calculation etc. are done in the office. It involves the use of triangles except where the land being surveyed forms a perfect rectangle upon which the detail is built.This is most suitable adapted to small plane areas with very few details. It can be used to fill in details on a map whose larger features have been surveyed by other methods.Is known as chain/tape surveying method because its main instrument used is chain or tape.The necessary requirements for field work are chain, tape, ranging rod, arrows and sometime cross staff.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLChain survey is suitable in the following cases:Area to be surveyed is comparatively smallGround is fairly levelArea is open Details to be filled up are simple and less EQUIPMENT USED IN CHAIN/TAPE SURVEYFor doing chain surveying, the following are the necessary equipments (tools):-1.CHAINIs made up of steel wire consisting of long links so that it can easily bend.Is used for taking linear measurements on a straight line. It has measure length of 20m or 30m long.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOL2.TAPE MEASUREIs also called ta tape measure or measuring tape.Is made up of steel or fiber glass with lengths either 2m, 5m, 10m,30m or 50m.Like a chain, tape is used to measure short & straight distances.3.SURVEYOR’S BANDIt looks like the tape but the only difference the length can be 30m,50m up to 100m; and it is rolled into a mental frame with a winding handle.Also it used to measure straight distances during surveying.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOL4.CROSS STAFFIs an instrument used to set out right angles from the lineIt can be made up of wood or steel & has eye slits at right angles.5.RANGING RODSAre poles about 2m or 3m long, used for making stations or aligning the line to be measured.Are normally made up of wood with a pointed metal end so that can stick in the ground firmly.Are painted black/re and white to make them visible.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOL6.ARROWSAre skewer- like metal rods about half a metre (50m) long for marking ends of a complete chain/tape.Are coiled or rounded at at one end & pointed at the other end.7.PEGSAre sometimes called wooden pegs as they are made up from hard timber.Have a length of 50cm & they are used to mark positions permanently during the exercise of surveying.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOL8.FIELD NOTEBOOK & A PENCILIs a special notebook & a pencil are required for recording all the necessary information. 9.PLUMB BOB In measuring horizontal distances along sloping ground plumb bobs are used to transfer the position to ground.They are also used to check the verticality of ranging poles.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOL10.Offset rodsThese rods are also similar to ranging rods and they are 3m long. They are made up of hard wood and are provided with iron shoe at one end.A hook or a notch is provided at other end.At height of eye, two narrow slits at right angles to each other are also provided for using it for setting right angles.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLCHAIN SURVEY PROCEDURESFor conducting chain surveying, several steps (procedures) are to be followed.The procedures can be grouped into three parts as follows:1.INSPECTION OF THE AREAWalk around the area & select positions for the stations while noting down:Adjacent stations should be inter-visible.Lines joining adjacent stations should run along the ground which is easy to walk along.Mainlines should be as few as possible & should be sited where they can be used to pick detail as possible.Choose the main triangle which should be as large as possible with at least two sides running close to an outside boundary of the survey & whose sides pass clear of obstructions to measurement.It should not contain very acute angles but one angle may be apprx 90o.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLMark the corners using ranging poles.Whole surveyed area should be covered by triangles (Triangulation) but note that, 'no part of the area should lie more than 9m outside the framework of triangles'.Starting from the main triangle, build up secondary lines of the survey framework (mind that: all points “minor stations” will have to be fixed by intersection or by measuring along the sides of the triangle.A chain line should run along-side every fence, edge or other boundary.At least all the stations which do not lie on the chain lines should be fixed & marked.By using rough tape or pacing, get an idea of maximum dimensions of the survey that will help in working out the scale.Make a sketch of the area; show the survey lines to be used (including the stations & a few details to enable identification.Sketch should resemble the shape of the area.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLThe simplest chain survey would be one triangular field where one triangle would supply all the triangulated framework necessary.The more complex one, will involves several triangles. Along ' backbone' will be necessary & from this triangles can be constructed.MEASUREMENT OF DETAILThis is done by the following methods:(I) Perpendicular offset: An imaginary perpendicular is dropped from the point of detail to the survey line.As a rule, where perpendicular offsets have to be guessed, the distance from the detail to the survey line (offset) should not exceed 9m.(II) Tie lines: This is more useful when the distance from the detail to the survey line exceeds 9m. Two suitable points on the survey line are picked & their distances are booked.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLThen lines from @ of these points are measured to the detail & the distances recorded.These lines are the tie lines.The accuracy of this method would depend on the receiving angle.The nearer this is to 90o, the more accurate the detail can be fixed. All in all, the procedure of inspection of the area is referred to as Reconnaissance.A reconnaissance survey is a preliminary stage of surveying whereby the surveyor gets familiar with the area to be surveyed by walking around, taking general views as well as noting down the dominant features in the area.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLSURVEYING IN THE FIELDFor measuring chain lines, three persons are required (a Leader[L], a Follower[F] & a Booker [B])FOLLOWER is in charge of the measurements while the BOOKER is the one who keeps records in the field notebook. FOLLOWER puts down one end of the chain against the pole @ the first station. LEADER holds the other end of the chain carrying it towards the next station.When the “L” reaches the end of the chain, he/she places one arrow upright and is guided by the “F” so that the arrow is in line.Then he/she pulls the chain tight & sticks the arrow into the ground. If there are any offsets or tie lines which have to be measured, the chain is left on the ground & measurements are taken.”L” drags the chain forward until the “F” reaches the first arrow left by the “L”. He/she holds one end of the chain while the “L” aligns an arrow as directed by the “F”

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOL Then, necessary measurements are taken & “F” picks up the arrow & moves forward to the next arrow. =>> This procedure is repeated as before. If the ground is too hard for an arrow to stick, “F” draws a point where the arrow should stick & leaves the arrow pointing @ point. @ end of the line, the “F” will have collected the # of arrows equal to the # of chain lengths measured. ”L” runs short of arrows, “F” hands over his arrow , & this is recorded by “B”.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLPRESENTATION OF DATA/RECORDING Involves recording of data in a form that can be interpreted & understood by others. Presentation of the measurements made in land survey is in the form of maps, plans or diagrams with the information recorded on the drawings by: Scale representationUses of conventional signsTabulation of notesMeasured & calculated data The most suitable method of presenting the information depends on the nature of the survey work.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLRANGING AND CHAINING RANGING: Is an activity of sub-dividing the survey line by using ranging poles. Ranging is done so as to get accurate measurements especially for long distances. CHAINING: Is an activities of measuring those sub-divisions, & is done by using a chain.FIXING THE NORTH POINT Is important to know the North-South line during the survey. This is done by using a compass & marking a North-South line on the ground & consequently entering this in the field book. Otherwise, one can determine the bearing of one of the chain lines & from that one can work out the North point.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLMEASUREMENT OF OFFSETS Is done by using the method for perpendicular offsets or tie lines.MEASUREMENTS ON SLOPING GROUND A map shows the horizontal distance btn two points & not the distance along the slope. Thus, should the slope have a gradient steeper than 12, a method used is known as STEEPING Often, by using steeping is easier to chain downhill than uphill. “F” holds the chain in place & “L” who will be downhill, raises the chain off the ground & holds it as horizontal as he /she can against a ranging pole which must be vertical. Then., he/she replaces the pole with an arrow & chaining continues.CHAINING AROUND OBSTACLES Obstacles may appear on the way of the chain line. The following are some of simple methods that can be applied for doing chain survey across obstacles.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLMETHOD IExample you chain surveying across a pond.Steps (I): Fix poles/arrows @ A & B exactly aligned along the chain line Set out equal perpendicular @ A & B such that AC=BD and they clear the obstacle. CD = AB, so CD is measured as though it were AB.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLORSteps (II): On reaching Y, set out line YP @ a suitable angle such that it clears the obstacle & YO=OP. XO is measured & produced to Q such that XO = OQ. The distance XY across the pond = PQ since XOY and POQ are similar triangles.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLORSteps (III): @ X, measure a line XQ and on it fix P such that XP=PQ. Measure YQ and fix R such that YR=RQ. 2PR=XY.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLMETHOD IIExample you chain surveying across a house.Steps: BAGH is along the chain line. Set out equal perpendiculars AC & BD Look along DC & set out E & F in alignment,but beyond the obstacle. @ E & F, set out perpendiculars EG & FH both equal to AC G & H are in line with BA & CE=AG

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLMETHOD IIIExample you chain surveying across an obstacle that is wider than one chain & can not be walked around (Eg. River).Steps: A & B lie along the line of survey XY & are marked. AQ is set off @ right angle to XY & a pole is fixed @ O, midway btn AQ. From Q, set out a line @ right angle to AQ & along this line, place a marker such that it will be in line with O & B. (This is point P). PQ // AB, so triangles AOB & QOP are similar. So, AB=QP

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLBOOKING ENTRIES IN THE FIELD BOOK Booking is a responsibility of a Booker (B). Record-book should have long pages such as A4 size. On @ page, two parallel lines are drawn in the middle of the page, apprx 2cm apart. Middle column represents the chain line.PROCEDURES TIO FOLLOW:A: Start to record @ the bottom of the page & proceeds towards the top of the page. Title of the survey & the units of measurements are recorded first at the bottom of the page & a line is drawn above this entry.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLB: @ station is shown by a circle & a dot in the middle & is placed to the left of the middle column.C: @ station starts at zero & the figures in the middle column shows points along the chain. @ the end of a chain line, the value is encircled.D: Perpendicular offsets are shown by figures, i.e value on appropriate side of the middle column.E: Tie lines are drawn & measurements written on @ line.(this must start from the figures showing the point on the chain line.F: Sketches are essential & measurements on them should be shown.G: The name of the chain line should be shown (Eg. A to B; B to C).

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLADVANTAGES OF CHAIN SURVEY Is a simplest and commonest method used in surveying exercises. The equipment used to conduct chain survey are simple to use. The equipment used in chain survey can easily be replaced. For example measuring rods can be replaced with measuring tape. This method does not involve complicated mathematical calculation. Enable us to make quick measurements of small areas of flat or nearly flat & associated objects. Is applicable in adding new information to existing plans or large scale maps. Example: adding the new details of National Stadium to existing map of Dar es Salaam City. Is useful in planning (Eg. arrangement of rooms). It is economical since it needs few people to conduct it (normally chain survey team has three people Booker, leader and follower).

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLDISADVANTAGES OF CHAIN SURVEY It is time consuming exercise since the equipments used are for measuring short distance. Is subjected to the accumulation of errors especially where large areas are involved. Its procedures are a tiresome exercise since the instruments used (chain) are heavy. Is an oldest type of survey & can not match the new world of “S & T”. Is not suitable on land with varying gradients or where there are large obstacles.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLLIMITATIONS OF CHAIN SURVEY Chain survey becomes more complicated method when there are raised points (obstacles) in between areas to be surveyed. It may not be conducted in areas with steep slopes or water logged areas. Is limited to small areas & can not be used when surveying large areas like the whole of Tanzania. Is not suitable for surveying dense forested/mountainous areas & even heavily built up areas.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLLEVELLING SURVEY Leveling is the measurement of geodetic height using an optical leveling instrument and a level staff or rod having a numbered scale. Levelling is the determination of the relative heights of various points on the Earth's surface. These relative heights are called levels. Levelling survey deals with measurement of different levels.EQUIPMENT USED IN LEVELLING SURVEYCommon leveling instruments include: Levelling staff Spirit level / bubble tube Tripod stand Abney level

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLLEVELLING STAFFIt looks like a big ruler (about 4m long) & used for recording differences in height btn points.Is graduated in such a way that one can read it easily from a distance.SPIRIT ,LEVEL OR BUBBLE TUBEIt used for generating horizontal line of sight.Also it used to take readings from the levelling staff.Is put on a tripod stand during the exercise of levelling surveying.TRIPOD STANDIs used to hold a spirit level so that it can sight a point horizontally.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLABNEY LEVEL Is used to measure degrees, % of grade, topographical elevation & a chainage correction. Note: Other instruments used in levelling surveying are Measuring tape & Ranging rods.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOL

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOL Firstly, find the difference in readings btn the two levelling staffs ( 2.530m – 1. 320m = 1.210m ) The height of point A is 437.670m. So, the height of point B will be obtained by adding the readings difference btn two levelling staffs ( 437.670m + 1.210m = 438.880m ). Units of B are more than those @ station A, indicating a Rise. LEVELLING METHODS There are two simple methods used to determine the difference in levels btn two points. But the height of one point should be known.I: RISE FALL METHOD Levelling instruments should be placed as shown in the diagram:

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOL

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLOtherwise;II: COLLIMATION METHOD This method uses the collimation level/ height (which is obtained through calculations of heights of points along a stretch of land). Height of collimation line is obtained by adding the staff reading of a point of known level to the points of known height.TO THE BELOW DIAGRAM: Height of collimation is A's height (635.562m + 1.743m = 637.305m). Reading of the levelling staff placed @ A is 1.743m

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOL

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLSIGNIFICANCE OF LEVELLING Helps us to determine the relative heights of various points on the Earth's surface. Heights obtained can be used in drawing of contour lines (where three methods can be used).Gridding Method: Is suited to gently sloping to undulating land & to fairly small areas.Radiation: Is useful where there are small hill in the area to be mapped. Direct contouring: Is best used for hilly terrain. Is used to produce longitudinal sections of roads. Is used to obtain a concrete cross sections of man-made features @ selected points @ right angles to the longitudinal line.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLDISADVANTAGES OF LEVELLING It involves a lot of movements from time to time especially when changing directions & distance measurements. Accuracy of the dutum line in measuring heights is sometimes made difficult by reference points Levelling (by using abney level) is a very crude & laborious method.REVISION AND QUESTIONSTASK Use simple survey tools to practice chain/tape surveying.

2/11/2015GEOGRAPHY DEPARTIMENT @ LUSHOTO SEC SCHOOLASSIGNMENT1. Define the following terms: Surveying Chain survey Topographical survey Cadestral surveying2. What is the difference btn the following: Geodetic surveying and Plane surveying Chain and Tape measure Ranging rods and Pegs3.Name any five essential equipments used in chain/ tape surveying.4.What is Triangulation as used in chain surveying?5.Mention the different methods of taking measurements in chain surveying and gives their differences.6.What is the purpose of carrying out land surveying?7.Explain the main social and economical importance of chain surveying.THANKS & LET GOD BLESS YOU !© Mr. Gunda W.C.