30 40 50 made easy

Karl Zeiske

presented by: Virtual Archive of www.wild-heerbrugg.com Introduction

This booklet will tell you • What are the main The use of levels and total instruments available today about the basic principles features of these stations is illustrated by a from Leica Geosystems; of surveying. instruments? series of practical neither does it touch on examples. In addition, their individual performance The most important • What needs to be taken applications programs are features. These aspects are instruments for surveying into account when described; these are covered by the com- are levels and total stations; measuring with a level or incorporated into the prehensive brochures, by the they are intended for with a total station? modern total stations technical consultants in the routine survey tasks. manufactured by Leica Leica Geosystems agencies, Anyone wishing to know • What are the effects of Geosystems and they solve and by the home pages in how and where they are instrument errors? survey tasks even more the Internet used will find the answers easily and elegantly. (www.leica-geosystems.com). here. • How can such errors be Equipped with the recognized, determined knowledge in this booklet, and eliminated? and with the help of the appropriate user manual, • How can simple anyone can carry out surveying jobs be simple survey tasks performed? confidently and efficiently. This booklet does not describe the range of

2 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com Contents

The level 4 Measuring distances without a reflector 19 Automatic target recognition 19 The total station 5 Setting out profile boards 20 Coordinates 6 Measuring angles 7 Instrument errors 22 Inspecting the line of sight 22 Preparing to measure 8 Inspecting the EDM of the total station 23 Setting up the instrument anywhere 8 Instrument errors in the total station 24 Levelling-up the instrument 8 Setting up the total station Simple surveying tasks 26 over a ground point 9 Aligning from the mid-point 26 Measuring slopes 27 Measuring with the level 10 Measuring right-angles 28 Height difference between two points 10 Measuring distances optically with the level 11 Applications programs 29 Line levelling 12 Calculating areas 29 Staking out point heights 13 Staking out 30 Longitudinal and transverse profiles 14 Remote heights 31 The digital level 15 Tie distances 32 The rotation laser 15 Free-station surveys 33

Measuring with the total station 16 The applications programs available 34 Extrapolating a straight line 16 Polar setting-out of a point 16 Surveying with GPS 35 Plumbing down from a height point 17 Surveys (polar method) 18

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 3 The level

A level essentially comprises a telescope rotatable about a vertical axis; it is used to create a horizontal line of sight so that height differences can be determined and stakeouts can be performed.

The Leica Geosystems levels are also equipped with a horizontal circle that is very useful for setting out right angles, e.g. during the recording of transverse profiles. In addition, these levels can be used to determine distances optically with an accuracy to 0.1 – 0.3 .

4 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com The level • The total station The total station

A total station consists of a Leica total stations are with a built-in supplied with a software distance meter (distancer), package that enables and so it can measure most survey tasks to be angles and distances at the carried out easily, quickly same time. Today’s and elegantly. The most electronic total stations all important of these pro- have an opto-electronic grams are presented in distance meter (EDM) and the section "Applications electronic angle scanning. programs". The coded scales of the horizontal and vertical Total stations are used circles are scanned wherever the positions electronically, and then the and heights of points, or angles and distances are merely their positions, displayed digitally. The need to be determined. horizontal distance, the height difference and the coordinates are calculated automatically and all measurements and additional information can be recorded.

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 5 Coordinates

In order to describe the Direction of reference Abscissa (x) position of a point, two P coordinates are required. y P Polar coordinates need a line and an angle. Cartesian coordinates need D two lines within an x orthogonal system. α The total station measures polar coordinates; these are recalculated as Ordinate (y) Cartesian coordinates within the given Polar coordinates Cartesian coordinates orthogonal system, either within the instrument itself X or subsequently in the office. Recalculation Y P

given: D, α given: x,y required: x,y required: D, α

y = D sin α D = ÷ √y2 + x2 D x = D cos α sin α = y/D or X cos α = x/D α

Y

6 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com The level • The total station Measuring angles

An angle represents the The vertical angle is difference between two therefore correct only if the directions. zero reading of the vertical circle lies exactly in the Zenith The horizontal angle α zenith direction, and also between the two directions this stipulation is met only leading to the points P1 under ideal conditions. and P2 is independent of the height difference Deviations from the ideal P1 between those points, case are caused by axial provided that the telescope errors in the instrument always moves in a strictly and by inadequate vertical plane when tilted, levelling-up (refer to whatever its horizontal section: "Instrument orientation. This stipulation errors"). Z1 is met only under ideal Z2 P2 conditions. Z1 = zenith angle to P1 Z2 = zenith angle to P2 α The vertical angle (also termed the zenith angle) is α = Horizontal angle the difference between a between the two prescribed direction directions leading to (namely the direction of the points P1 and P2, the zenith) and the i.e. the angle between direction to the point under two vertical planes consideration. formed by dropping perpendiculars from P1 and P2 respectively Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 7 Setting up Levelling-up the instrument the instrument anywhere After setting up the consists basically of a instrument, level it up thread-suspended mirror approximately with the that directs the horizontal 1.Extend the legs of the bull’s-eye bubble. light beam to the centre of tripod as far as is the crosshair even if there required and tighten the Turn two of the footscrews is residual tilt in the tele- A B screws firmly. together in opposite scope (illustration, bottom). directions. The index finger 2. Set up the tripod so that of your right hand indicates If now you lightly tap a leg C the tripod plate is as the direction in which the of the tripod, then (pro- horizontal as possible bubble should move vided the bull’s-eye bubble and the legs of the (illustration, top right). is centred) you will see how tripod are firm in the Now use the third footscrew the line of sight swings ground. to centre the bubble about the staff reading and (illustration, bottom right). always steadies at the 3. Now, and only now, same point. This is the place the instrument on To check, rotate the instru- way to test whether or not the tripod and secure it ment 180°. Afterwards, the the compensator can swing with the central fixing bubble should remain freely. A B screw. within the setting circle. If it does not, then readjustment is required (refer to the user C manual).

For a level, the compen- sator automatically takes care of the final levelling- up. The compensator

8 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com Preparing to measure Setting up the total station over a ground point

1.Place the tripod approxi- 5.Centre the bull’s-eye mately over the ground bubble by adjusting the point. lengths of the tripod legs (illustration below). 2.Inspect the tripod from various sides and correct 6.After accurately levelling its position so that the up the instrument, re- tripod plate is roughly lease the central fixing horizontal and above the screw so that you can ground point (illustration, displace it on the tripod top left). plate until the laser dot is centred precisely over 3.Push the tripod legs the ground point. firmly into the ground and use the central fixing 7.Tighten the central fixing screw to secure the screw again. instrument on the tripod.

4.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).

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 9 Height difference between two points

The basic principle of The height difference is levelling involves calculated from the determining the height difference between the two difference between two staff readings for the points points. A and B respectively.

To eliminate systematic R = backsight V = foresight errors related to atmospheric conditions or B to residual line-of-sight error, the instrument should be about equidistant from the two A points. ∆H = R -V = 2.521 - 1.345 = 1.176 Reading: 2.521 Reading: 1.345 27 15

26 14

25 13

24 12

23 11

10 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com Measuring with the level Measuring distances optically with the level

The reticle carries two Example: stadia lines arranged Reading on upper symmetrically to the stadia line B = 1.829 crosshair. Their spacing is Reading on lower B such that the distance can stadia line A = 1.603 be derived by multiplying Staff section the corresponding staff I = B-A = 0.226 section by 100. (This Distance = 100 I = 22.6 m diagram is a schematic A representation).

Accuracy of the distance measurement: 10 – 30 cm

D

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 11 Line levelling

If the points A and B are 4. Set up the instrument at widely separated, the S2 (the staff remains at height difference between the turning point 1). R V them is determined by line RV levelling with target 5. Carefully rotate the staff RV distances generally at the turning point 1 so H between 30 and 50 metres. that it faces the B instrument. S1 Pace out the distances A 1 S3 ∆H between the instrument 6. Read off the backsight S2 2 and the two staffs; they and continue. need to be about the same.

1. Set up the instrument The height difference Station Point Backsight R Foresight V Height Remarks no. at S1. between A and B is equal A 420.300 to the sum of the backsight S1 A +2.806 2. Set up the staff precisely and the foresight. 1 -1.328 421.778 = height A+R-V vertically at point B; read S2 1 +0.919 2 -3.376 419.321 off and record the height S3 2 +3.415 (backsight R). B -1.623 421.113 Sum +7.140 -6.327 3. Set up the staff at the -6.327 +0.813 = height B – height A ∆ H +0.813 = height difference AB turning point 1 (ground plate or prominent ground point); read off and record the height (foresight V).

12 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com Measuring with the level Staking out point heights

In an excavation, a point B In another frequently-used is to be set out at a height method, the required staff 9 H = 1.00 below reading is calculated in 9 ∆ 9 street level (Point A). advance: 9 9 9 V= R - H = 1.305 - (-1.000) 9 9 ∆ 9 9 9 9 1.Set up the level so that = 2.305 9 9 9 9 9 9 9 the sighting distances to The levelling staff is then 9 9 9 9 9 9 A and B are about the moved upwards or down- 9 9 9 9 9 same. wards until the required 9 9 9 9 B value can be read off with A 2.Set up the staff at A the level. and read off the backsight R = 1.305.

3.Set up the staff at B and read off the foresight V = 2.520.

The difference h from the required height at B is R=1.305 V=2.520 calculated as: h = V – R - ∆H = 2.520 – 1.305 – 1.00 = +0.215m A 4.Drive in a post at B and ∆H= 1.00 m ∆H mark the required height h= +0.215 m (0.215m above ground B level).

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 13 Longitudinal andtransverseprofiles 14 the aidof known profile aredetermined with points inthetransverse ground heightsforthe are thenrecorded.The right-angles totheroadline) tures, transverseprofiles(at prominent topographicfea- the stationpointsandat mined bylinelevelling.At station pointsbeingdeter- roadline, theheightsof then createdalongthe A longitudinalprofileis marked atregularintervals. points areestablishedand stationed; thismeansthat line) isstakedoutand the longitudinalaxis(road- the topography. Firstofall modation oftheroutesto for thebestpossibleaccom- for thecalculationoffilland routes (e.g.roads)andalso stakeout ofcommunications the detailedplanningand profiles formthebasisfor Longitudinal andtransverse height (illustration above). related toaround reference tudinal direction, whichis the stationingoflongi- 10x greater)thanthatof at amuchbiggerscale(e.g. station pointsareexpressed cally, theheightsof longitudinal profilegraphi- level. Whenrepresentinga tape oropticallyusingthe either withthesurveyor profiles aredetermined points inthetransverse station pointtothevarious The distancesfromthe points involved. this givestheheightsof from theinstrumentheight; the transverseprofile) readings (atthepointson Now subtractthestaff and thestationpointheight. sum ofthestaffreading ment heightcomprisesthe station point;theinstru- sition thestaffataknown po- First, instrument height. Virtual Archive of WILD ’ s Heerbrugg

Transverse profile175 Reference height:420m Roadline Longitudinal profile (planned)

Reference height:420 m www.wild-heerbrugg.com

100 125

25 m 150 424.00

423.50 175 423.50 424.00

(planned height) 200

Terrain Measuring with the level The digital level

The digital levels from Leica the staff stations are calcu- The rotation laser Geosystems are the first lated continuously and so ones in the world to be there can be no errors re- equipped with digital elec- lated to reading, recording tronic image processing for and calculating. Leica Geo- If, on a large construction the determination of heights systems can offer software site for example, a large and distances; the bar code packages for post-pro- number of points at on a staff is read by electro- cessing the recorded data. different heights need to be nic means, completely auto- staked out or monitored, matically (see illustration). A digital level is recom- it often makes sense to use mended for use where a lot a rotation laser. In this type The staff reading and the of levelling needs to be of instrument, a rotating distance are displayed carried out; under these laser beam sweeps out a digitally and can be recor- circumstances the saving horizontal plane, which ded; the heights of in time can amount to 50%. serves as the reference plane for staking out or monitoring heights such as four-foot marks.

A detector is slid down a levelling staff until it encounters the laser beam; the height can then be read directly from the staff. There is no need for an observer at the instrument station.

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 15 Extrapolating a straight line Polar setting-out of a point

1.Position the instrument 4.Transit the telescope The setting-out elements 3.Rotate the instrument at point B. again and mark the point (angle and distance) here until a appears in the C2. Point C, the mid-point relate to a known point A display. 2.Target point A, transit the between C1 and C2, and to a known starting telescope (i.e. reverse it) corresponds exactly to direction from A to B. 4.Guide the reflector and mark point C1. the extrapolation of the carrier (person) into and line AB. 1.Set up the instrument along the line of sight of 3.Turn the instrument 200 at point A and target the the telescope, continually gon (180°) and target A line-of-sight error is re- point B. measuring the horizontal point A again. sponsible for the discre- distance until point P is pancy between C1 and C2. 2.Set the horizontal circle reached. to zero (refer to the user Where the line of sight is in manual). order, the influence of the errors is a combination of B target error, tilting-axis error and vertical-axis error.

C1

C AB P C2 α D A

16 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com Measuring with a total station Plumbing down from a height point

Plumbing down from a The mid-point between the For work of this type, make height point, plumbing up points B and C is the exact sure that the total station from a ground point, and plumbing point. has been levelled up pre- inspecting a vertical line on cisely, so that the influence a structure, can be carried The reason why these two of vertical-axis tilt on steep out exactly in just one tele- points do not coincide can sights is minimized. scope face, but only if the be a tilting-axis error telescope describes a pre- and/or an inclined vertical cisely-vertical plane when axis. it is tilted. To ascertain that this is so, proceed as A follows:

1.Target a high point A, then tilt the telescope downwards and mark the ground point B.

2.Transit the telescope, and repeat the procedure B in the second face. Mark C the point C.

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 17 Surveys (polar method)

To create e.g. a location plan, the position and height of a point on the object are determined by measuring angles and distances. To do this, the instrument is set up on any prominent point in a local coordinate system. A second prominent point is selected for the purposes of orientation; after this has been targeted the horizontal circle is set to zero (refer to the user manual).

If a coordinate system already exists, set up the instrument on a known point within it and line up the horizontal circle with a second known point (refer to the user manual).

18 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com Measuring with the total station Measuring distances without a reflector

Each of the TCR total The "DISTO" hand-held Automatic target recognition stations from Leica laser meter from Leica Geosystems includes not Geosystems is another only a conventional infra- simple instrument that red distancer that measu- uses a visible laser beam res to prisms, but also an and needs no reflector; it is The TCA total stations from after establishing the initial integrated laser distancer particularly suitable for Leica Geosystems are contact with the target the that requires no reflector. indoor measurements to equipped with an automatic instrument locks on to it You can switch between ascertain spacings, areas target-recognition system and tracks it. The practical these two distancers. and volumes. ("ATR"). This makes tar- applications of this option geting faster and easier. It is include the precise This arrangement brings enough to point the tele- guidance of construction many advantages where scope approximately at the machinery. points are accessible only reflector; a touch on a with difficulty or not at all, button then automatically Advantages of ATR: High for example during the triggers the fine pointing speed of measurement, recording of frontages, in and the angle- and distance combined with a constant positioning pipes and measurements, and records measuring accuracy that for measurements across all of the values. This is independent of the gorges or fences. technology also makes it observer. possible to carry out fully- The visible red laser dot is automatic measurements also suitable for marking with the help of a computer. targets in connection with the recording of tunnel The ATR can also be profiles or with indoor switched to a mode in work. which moving targets can be followed and measured;

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 19 Setting out profile boards

During building alignment, 2.Mark the point A at the 6.The points on the profile it is useful to extrapolate defined distance d from boards are then set out the sides of the building to the upper boundary; it in a similar manner, beyond the limits of the ex- will be the first location starting from the points cavation and there to erect for the total station. A1 to A6 respectively. profile boards on which the extensions are marked 3.Using a boning rod, mark If the foundations have not exactly by hammering in the point B at the end of yet been excavated, you nails. These can be connec- the baseline. can set out the sides H1H2 ted to strings or wires at and H1H3 of the building any time during the con- 4.Set up the total station on directly and use them as struction sequence, indi- point A, target point B, the starting line for cating the required and set out the points A1, marking the points on the positions of the walls. A2 and A3 in this align- profile boards. ment in accordance with In the following example, the planned length of the For smaller buildings it is profile boards are to be side of the building. easier to set out the profile erected parallel to the pro- boards using an optical posed walls of a large 5.With point B sighted, set square (right-angle prism) building and at distances of the horizontal circle to and a measuring tape. a and b respectively from zero, turn the total station the boundaries (illustration, by 100 gon (90°) and set A building-alignment left). out the second line AC software program with the points A4, A5 incorporated into many 1.Establish a baseline AB and A6. Leica total stations enables parallel to the left-hand profile boards to be set out boundary and at a freely- directly, starting with any selectable distance c. instrument station.

20 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com Measuring with the total station

a

A d A4 A5 A6 b

A 1 H1 H3

c

A2

A3 H2

B

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 21 Inspecting the line of sight (two-peg test)

In new levels, the com- 3.Read off from both staffs pensator has been adjusted and calculate the height 1.549 1.404 at room temperature, so difference (illustration that the line of sight is hori- above). zontal even if the instru- Staff reading A = 1.549 ment is tilted slightly. This Staff reading B = 1.404 situation changes if the ∆H = A – B = 0.145 B temperature fluctuates by A ∆H more than ten or fifteen 4.Set up the instrument dd degrees, after a long jour- about one metre in front ney, or if the instrument is of staff A and take the 30m subjected to strong vibra- staff reading (illustration tion. It is then advisable to below). inspect the line of sight, Staff reading A = 1.496 particularly if more than one target distance is 5.Calculate the required being used. reading B: Staff reading A = 1.496 1.In flat terrain, set up two - ∆H = 0.145 staffs not more than 30 Required reading ActualIst 1.496 SollRequired 1.351 1.351 metres apart. B = 1.351

2.Set up the instrument 6.Take the staff reading B. B so that it is equidistant If it differs from the A ∆H from the two staffs (it required reading by more is enough to pace out the than 3mm, adjust the line distance) of sight (refer to instruction manual).

22 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com Instrument errors Inspecting the EDM of the total station

Permanently mark four runs within the range typical for the user (e.g. between 20 m and 200 m).

Using a new distancer, or one that has been cali- brated on a standard baseline, measure these distances three times. The mean values, corrected for atmospheric influences (refer to the user manual) can be regarded as being the required values.

Using these four runs, mea- sure with each distancer at least four times per year. Provided that there are no systematic errors in excess of the expected measuring uncertainty, the distancer is in order.

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 23 Instrument errors in the total station

Ideally, the total station between plumb line and user manual. Vertical-axis tilt Note: should meet the following vertical axis). does not rate as being an The instrument errors requirements: instrument error; it arises change with temperature, The effects of these three because the instrument has as a result of vibration, and a) Line of sight ZZ perpen- errors on the measurement not been adequately levelled after long periods of dicular to tilting axis KK of horizontal angles increase up, and measuring in both transport. If you want to b) Tilting axis KK perpen- with the height difference telescope faces cannot measure in just one face, dicular to vertical axis VV between the target points. eliminate it. Its influence on then immediately before c) Vertical axis VV strictly the measurement of the the measurements you vertical Taking measurements in both horizontal and vertical angles must determine the d) Vertical-circle reading telescope faces eliminates is automatically corrected by instrument errors and store precisely zero at the zenith line-of-sight errors and means of a two-axis them. If these conditions are not tilting-axis errors. The line-of- compensator. met, the following terms are sight error (and, for highly- V used to describe the precise total stations, also d) Height-index error i (the particular errors: the tilting-axis error, which is angle between the zenith generally very small) can direction and the zero K Z a) Line-of-sight error, or colli- also be determined and reading of the vertical mation error c (deviation stored. These errors are then circle, i.e. the vertical- from the right angle bet- taken into consideration circle reading when using ween the line of sight and automatically whenever an a horizontal line of sight), the tilting axis) angle is measured, and then is not 100 gon (90°), but Z b) Tilting-axis error a (devia- it is possible to take mea- 100 gon + i. K tion from the right angle surements practically free of between the tilting axis error even using just one By measuring in both faces and the vertical axis) telescope face. The deter- and then averaging, the c) Vertical-axis tilt (angle mination of these errors, and index error is eliminated; it their storage, are described can also be determined and V in detail in the appropriate stored. 24 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com Instrument errors

a i c

Vertical-axis tilt Height-index error (i) Line-of-sight error (c) Tilting-axis error (a) (V index) (Hz collimation)

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 25 Aligning from the mid-point

If intermediate points are 4.From point 3, align point to be aligned within a line 4 in the straight line 3 – A of measurement and each and continue in the same of the two end points manner until no further cannot be seen from the lateral deviations are other, proceed as follows: visible at the two inter- mediate points. 1.Select two points 1 and 2 (both approximately in the alignment) from which both end points A and E are visible. Use sight poles to mark the points.

2.From point 1, align point 2 in the straight line 1 – A A

3.From point 2, align point 3 in the straight line 2 – E 1 E

2 3 4

26 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com Simple surveying tasks Measuring slopes

If slopes are to be deter- Using the telescope, mined in % or to be staked determine the instrument out, e.g. for gutters, height i at the staff. pipelines or foundations, The vertical-circle reading two different methods are giving the zenith angle available. in gon or degrees can be reset to % (refer to user 1. With a level manual) so that the slope Measure the height can be read off directly ∆H difference and the in %. The distance is distance (either optically irrelevant. D with the stadia hairs or with the tape). The slope A reflector pole fitted with is calculated as follows: a prism can be used 100 ∆H / D = slope in % instead of the staff. Extend the reflector pole to the 2. With a theodolite or instrument height i and use total station the telescope to target the Place the instrument on centre of the prism. a point along the straight line the slope of which is to be deter- V% mined, and position a i staff at a second point along that line. i

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 27 Measuring right-angles

The most accurate way to central fixing screw of the an unrestricted view of the set out a right-angle is to tripod. Then turn the object point. You as the use a theodolite or a total horizontal circle by hand to observer can position station. Position the zero in the direction of the yourself in the survey line instrument on the point survey line or of the (defined by two vertically- along the survey line from longitudinal profile. Finally, positioned alignment rods) which the right-angle is to turn the level until the in that you move perpen- be set out, target the end index of the circle is set to dicularly to the line until point of the survey line, set 100 gon (90°). you see the images of the the horizontal circle to zero two rods exactly super- (see user manual) and turn An optical square is the imposed. Then you move the total station until the best solution for the yourself along the survey horizontal circle reading is orthogonal surveying of a line until the object point 100 gon (90°). point on a survey line or and the two images of the vice versa, and for the alignment rods all coincide. For setting out a right- setting out at right-angles angle where the accuracy of a point in the near requirements are less distance. The beam of light demanding, e.g. for small from the object point is buildings or when turned through 90° by a determining longitudinal pentagonal prism so that it and transverse profiles, the reaches the observer. The horizontal circle of a level optical square consists of can be used. Set up the two superimposed level over the appropriate pentagonal prisms with point of the survey line their fields of view facing with the help of a plumb right and left respectively. bob suspended from the Between the two prisms is

28 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com Applications programs Calculating areas

1. Set up the total station in the terrain so that it is within view of the entire area to be surveyed. It is not necessary to position the horizontal circle.

2. Determine the boundary points of the area sequentially in the B clockwise direction. You must always measure a A distance. C 3. Afterwards, the area is calculated automatically at the touch of a button and is displayed. D

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 29 Staking out

1. Set up the instrument at Alternatively, the coordi- a known point and nates of the points to be position the horizontal staked out can be trans- circle (refer to the sec- ferred beforehand, back in tion "Setting the station” the office, from the in the user manual). computer to the total station. Under these 2.Enter manually the coor- circumstances, in order to dinates of the point to be stake out, only the point staked out. The program number then needs to be automatically calculates entered. direction and distance (the two parameters needed for staking out). 3.Turn the total station N until the horizontal circle reads zero.

4.Position the reflector at this point (point P’). ∆D 5.Measure the distance; P the difference in the distance ∆D to the point P' P will be displayed α automatically.

30 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com Applications programs Remote heights

1. Set up a reflector verti- cally beneath that point the height of which is to be determined. The total station itself can be situated anywhere.

2.Measure the distance to the reflector. H 3.Target the high point.

4.The height difference H between the ground point and the high point is now calculated at the touch of a button and is displayed.

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 31 Tie distances

The program determines the distance and height difference between two points.

1.Set up the total station at any location.

2.Measure the distance to each of the two points A and B.

3.The distance D and the D B height difference H are H displayed at the touch of A a button.

32 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com Applications programs Free-station surveys

This program calculates The options for measuring, the position and height of and the measuring the instrument station, procedure, are described in along with the orientation detail in the user manuals. of the horizontal circle, from measurements to at Note: least two points, the When performing survey coordinates of which are tasks that involve known. determining heights or staking them out, always Hz=0 The coordinates of the tie remember to take the H points can be entered height of the instrument N (x) manually or they can be and that of the reflector stored in the instrument into account. beforehand.

Free stationing has the great advantage that, for large projects involving surveying or staking out, you can choose the most favourable station for the instrument. You are no longer forced to use a known point that is in an unsatisfactory location. E (y)

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 33 The applications programs available

Recording points Orientation and height transfer Resection Tie distance Staking out Remote heights Free-station surveys Reference line Hidden points Area computation Sets of angles Traversing Local resection COGO (computations) Automatic storage Scanning surfaces Digital terrain models Offset

34 Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com Surveying with GPS Surveying with GPS

GPS surveys use the tasks that until recently signals transmitted by were carried out using satellites having trajectories electronic total stations. such that any point on the Earth’s surface can be The new GPS System 500 determined around the from Leica Geosystems clock and independently of enables the most diverse weather conditions. The range of survey tasks to be positioning accuracy carried out with centimetre depends on the type of accuracy – on the tripod; GPS receiver and on the on the plumbing pole; on observation and post- ships, vehicles and processing techniques construction plant; and used. using both static and kinematic applications. Compared with the use of a total station, GPS surveying offers the advantage that the points to be measured do not have to be mutually visible. Today, provided that the sky is relatively unobstructed (by trees, buildings etc.) and there- fore that adequate satellite signals can be received, GPS equipment can be applied to many survey

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com 35 Leica Geosystems AG CH-9435 Heerbrugg (Switzerland) Illustrations, descriptions and technical data are not binding and may be changed. Printed in Switzerland. Phone +41 71 727 31 31 Copyright Leica Geosystems AG, Heerbrugg, Switzerland, 2000 Fax +41 71 727 46 73 722510en – VII.00 – RVA www.leica-geosystems.com

Virtual Archive of WILD Heerbrugg www.wild-heerbrugg.com