111
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Lecture 6: Tacheometry & Detail Surveys
Field proceduresElectronic data recordingComputer plottingChap. 9 (Uren & Price)
UNSW
Contents
'Breaking down' controlPlotting and scalesOlder mapping methodsModern 'field-to-finish' electronic surveysCase study
Detail Surveys: Some Comments
Heirarchy of control networks - - details surveys are 'connected' to control (providing starting coordinates).Detail surveys are used for many purposes.Detail surveys provide data for project design - -electronic data recording, input to CAD packages.Details surveys carried out at appropriate (plot) scale - -not 'general purpose'.Details surveys nowadays synonymous with "tacheometry".
Plotting
Plans have limited accuracy!!
Accuracy about 1/2 of line thickness+ drawing error ± 0.2 - 0.3 mm
At 1:1000 0.3mm is 30cm
Q: What scales are street directories ?
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Plan and Map Scales
Suburban cadastralEngineering constructionStreet directoryTopographic, bushwalkingRegionalAtlas
Typical values1:2001:5001:20,0001:25,0001:100,0001:1,000,000
Plane Table Mapping
A B
Drawing Board
Plane Table and accessories
PlumbLine
Alidade
222
'Chain' Surveys - Tape Only
4.81
14.67
Shed
Grass
7.46
0.71
4.222.00
3.730.60
2.41
0.48
Trees and shrubs
Grass Patio
Patio
-16.15-
-7.47-
-7.15-
House
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Optical Distance Measurement
Stadia Tacheometry:no electronicsslower and less accurate than electronic tacheometers
See Lecture 3 on Distances + text book
Theodolite + Tape Survey
G I ShedSilky Oak0.3d 10s
Gum0.2d 4sTea tree
0.1d 3sPalm0.2d 4s
W.C.
Brick & G.I. Roof
Conc.D’way
Conc.Driveway
QUEEN MARY ST
150 Conc K & GELP
PMG
Old P
aling0.23 w
ide
New Paling Lapped & Capped
KIN
GG
EOR
GE
SR
OA
D
ELP
Conc. B
lk Ret w
all
Post & rail
Bk. Fence 1.8 high
SV ELP
ELP
ELP ELP
G I ShedSilky Oak0.3d 10s
Gum0.2d 4sTea tree
0.1d 3sPalm0.2d 4s
W.C.
Brick & G.I. Roof
Conc.D’way
Conc.Driveway
QUEEN MARY ST
150 Conc K & GELP
PMG
Old P
aling0.23 w
ide
New Paling Lapped & Capped
KING
GEO
RG
ES
RO
AD
ELP
Conc. B
lk Ret w
all
Post & rail
Bk. Fence 1.8 high
SV ELP
ELP
ELP ELP
Theodolite + Tape Survey
G I ShedSilky Oak0.3d 10s
Gum0.2d 4sTea tree
0.1d 3sPalm0.2d 4s
W.C.
Brick & G.I. Roof
Conc.D’way
Conc.Driveway
QUEEN MARY ST
150 Conc K & G
ELPPMG
Old P
aling0.23 w
ide
New Paling Lapped & Capped
KIN
GG
EO
RG
ESR
OAD
ELP
Conc. B
lk Ret w
all
Post & rail
Bk. Fence 1.8 high
SV ELP
ELP
ELP ELP
Theodolite + Tape Survey
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Electronic Distance Measurement
INFRARED instruments, use prisms as reflectors, limited range (<5km), light and integrated within theodolite ("total station").LASER instruments, long range (30-60km), high accuracy.MICROWAVE instruments, very long range (up to 100km), not common for engineering applications.
333
B
A
DV Ht
Hi
Horiz Dis
∆h
RLB = RLA + h
= RLA + Hi + v - Ht
∆
Theodolite + Distance
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
EDM Tacheometry
Electronic tacheometers sometimes also called "total stations".Traversing, set- outs and detail surveys can be carried out rapidly.Electronic measurement of angle and distance, and data recording - - "field to finish" surveying.Feature coding using keyboard, barcodes, etc.Large variety of computer software for plan preparation.
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Principles of Tacheometric Surveys
Large-scale plans -- "detail surveys" Product is a planimetric or contour plan showing man-made and natural details.Many plans are now computer generated.Set-up instrument at point of known position and height.'Radiate' points of detail.
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Principles ...
Use check measurements.Calculate coordinates and height.Be aware of scale of finished plan:– (1:100 implies 1mm on plan is 0.1m on ground)
Spacing of natural surface points must reflect scale of plan and nature of terrain.
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Principles ...
May use grid, but prefer to locate change of ground slope.Contouring can be done automatically by plotting software.Survey trees (note trunk & crown diameters, variety, etc.).Detailed description of object. Pick up enough points to define curves.Pick up top and bottom of kerbs (for height difference, not plot).Particular attention around buildings (remember there are usually right-angled corners!).Always check for blunders, bumped instrument, etc.Better to have too many points than too few!
Computer Contouring
60
62
64
66
6858
56
54
5259.1 60.9
65.2
57.1
56.5 62.5
66.6
68.558.2
59.7 62.3
64.4
66.0
67.466.265.163.1
62.3 62.8
59.7
53.6
444
If you want heights or contours, measure height of instrument!
FL & FR Theodolite Measurements?
2 faces requires repeat obs, mean reduces random errors, differences detect gross errors.2 faces reduce systematic errors: axis tilt, collimation error, etc.2 faces does not reduce vertical axis (levelling) tilt or centring errorTraverse / control = 2 faces, Radiation = 1 face1 face obs faster & plotting requires low precision.
Electronic Data Recording
1. Measure and record data
2. Down load data into computer
3. Process and plot plans
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Field Coding
Record measurements:e.g. point ID, direction, ZA, slope distanceRecord codes or comments:e.g. date, height of target, coordinates,
feature ID / codes, etc.
555
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Feature Codes
Entity & strings, e.g. 40902 409 = top of kerb,
02 = join kerb points togethere.g. 00100203
001 = permanent survey mark00 = individual point, not a string
203 = point number / ID
100m
Detail Survey - Case Study
St John’s College, MorpethJuly 1998
Survey: G. Donovan, C. Reid, T. Rofe
Civilcad & Calcs: C. ReidPowerPoint: B.Harvey
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Control Traverse
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Control Traverse by another group Basic Surveying for Engineers: Detail Surveys
C. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Control Traverse by another group
666
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Triangular mesh
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
LEGEND
CLIENT: Mr.S.Ganeshan
SURVEYOR: Cameron.E.Reid,2174004
DATE: 22/08/98
LOCALITY: Morpeth
LGA: Maitland
SCALE 1:500DETAIL AND LEVEL SURVEY
AREA: Section 3 No:2 ,Closebourne Convention Centre.
SUBJECT: GMAT6052 Filed Projects 2
REFERENCE NUMBER: 980001
357800
357800
357900
357900
358000
358000
358100
358100
13769001376900
1377000 1377000
1377100 1377100
VEGETABLE
GARDEN
CARPARK
TENNIS
COURT
GREEN
STAND OF
TREES
BRICK
BUILDING
PLAYGROUND
GAS TANK
FIBRO
BUILD
SA NDSTO N
E
BUIL DI
N G
GRAV E
L
ROAD
BITUMEN
ROAD
BRICK BUILDING
(TILE ROOF)
BRICK
BLD
(TILE ROOF)
BITUMEN
ROAD
BRICK
BUILDI
NG
SANDSTONE
BUILDING
OLDSTONE
BLD
PRIVATE
PROPERTY
LAUNDRY
HOUSE
(TIMBER
AND ALUMUNIUM)
PP
PP
PP
LP
SUNDIAL 912
906
913
902916
917
914
915
901
911
910
PP
LP
GIP
GIP
FOOTPATH
FOOTPATH
STAND
OF TREES
35
35
35 35
35
35
35
35
35
35
35
35
35
35
35
FENCE
CLOTHES LINE
SEWERAGE PIT
NORTH
STATION
VERANDAH
POWER POLEPP
UNDERGROUND
WATER TANK
CONTOUR INTERVAL: 0.5m
RETAINING
WALL
NATURAL SURFACE
Final computer generated plan
LEGEND
CLIENT: Mr.S.Ganeshan
SURVEYOR: Cameron.E.Reid,2174004
DATE: 22/08/98
LOCALITY: Morpeth
LGA: Maitland
SCALE 1:500DETAIL AND LEVEL SURVEY
AREA: Section 3 No:2 ,Closebourne Convention Centre.
SUBJECT: GMAT6052 Filed Projects 2
REFERENCE NUMBER: 980001
357800
357800
357900
357900
358000
358000
358100
358100
13769001376900
1377000 1377000
1377100 1377100
VEGETABLE
GARDEN
CARPARK
TENNIS
COURT
GREEN
STAND OF
TREES
BRICK
BUILDING
PLAYGROUND
GAS TANK
FIBRO
BUILD
SA NDSTO N
E
BUIL DI
N G
GRAV E
L
ROAD
BITUMEN
ROAD
BRICK BUILDING
(TILE ROOF)
BRICK
BLD
(TILE ROOF)
BITUMEN
ROAD
BRICK
BUILDI
NG
SANDSTONE
BUILDING
OLDSTONE
BLD
PRIVATE
PROPERTY
LAUNDRY
HOUSE
(TIMBER
AND ALUMUNIUM)
PP
PP
PP
LP
SUNDIAL 912
906
913
902916
917
914
915
901
911
910
PP
LP
GIP
GIP
FOOTPATH
FOOTPATH
STAND
OF TREES
35
35
35 35
35
35
35
35
35
35
35
35
35
35
35
FENCE
CLOTHES LINE
SEWERAGE PIT
NORTH
STATION
VERANDAH
POWER POLEPP
UNDERGROUND
WATER TANK
CONTOUR INTERVAL: 0.5m
RETAINING
WALL
NATURAL SURFACE
Final computer generated plan
TENNISCOURT
STAND OFTREES
BRICK BUILDING
PLAYGROUND
SAN
DSTO
NE
BU
ILDIN
G
GR
AVELRO
AD
BRIC
K BU
ILDI
NG
(TIL
E RO
OF)
BRICKBLD
(TILE ROOF)
BRICK
BUILDING
SANDSTONE
BUILDING
PP
LP
SUNDIAL 912
913
914
PP
LP
GIP
FOOTPATH
FOOTPATH
STAN
DO
F TR
EES
35
35
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Large Scale Mapping: Comments
Large amount of digital data already available in GIS databases -- utilities, cadastral boundaries, etc.Low-level aerial photography can be used -- scanned and digitally converted to DTMs, etc.Metre-level satellite imagery/photography available.Future map 'products' will be result of data fusion from different sources, then 'draped', warped and viewed as 'fly-throughs' or VR landscapes.
Latest Developments
Robotic instruments.GPS, laser scanners, etc.Field computer screen plots.More complex, & realistic visualisations.
777
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Real-time Kinematic (RTK) GPS for detail surveys
• Requires 2 GPS receivers and a radio link for real-time differential positioning
• cm-level accuracy
• High productivity
• Not good under thick tree cover
• Compatible with most CAD softwares
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Photogrammetry
A plane equipped with a high resolution camera takes overlapping aerial photographs of the terrain.Adjacent pairs of photographs are oriented to replicate the aircraft position at time of exposureStereo images can be used to generate contours and detailTraditional method of map making – still in use although becoming more digital and automated
Courtesy http://www.crssa.rutgers.edu/courses/airphoto/airphoto7
Airborne laser scanning
Laser scanner is mounted in an aircraft and emits a laser beam which is reflected off the ground surfaceElevation of scanned surface can be determined by signal time-of-flightRequires accurate information of orientation and position of aircraft during flight
Courtesy AAM Surveys
3D laser scanning
Tripod mounted device, measures flight time of emitted radiation to produce a “point cloud” of 1000s of points. Data can be edited to produce 3D mapsUseful for structural monitoring and high definition surveying
Basic Surveying for Engineers: Detail SurveysC. Roberts, L. Ge, School of Surveying and SIS, UNSW, Bruce Harvey (c)
Summary
Traverse technique to 'bring in control'.Points or features of interest can be 'picked up' by radiating them using a tacheometer.Electronic measurement of angles & distance, and data recording (inc. attributes) -- "field to finish" surveying.Real-time high precision GPS techniques are increasingly used.'Measuring up' using tapes & offset techniques useful.Latest developments more suited to larger jobs requiring high productivity.