basic surveying lecture 1

8/20/2019 Basic Surveying Lecture 1

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Surveying I.

Lecture 1.

Sz. Rózsa: Surveying I. – Lecture


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Outline

Introduction

Historical Surveying

Surveying - Science andProfession

Methods of height determination

Levelling

The surveyors’ level



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Introduction

Lecturers

Dr. Szabolcs RózsaDepartment of Geodesy and Surveying,K. building groundoor 16.

Lectures

Practicals

Dr. Lóránt Földváry Department of Geodesy and Surveying,K. building groundoor 16.

r. !lbert "issDepartment of Geodesy and SurveyingK. building groundoor 16.



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Introduction

!ourse details

• "irst #art of a t$o-semester-course

• % hours&$ee' (e)ually divided *et$een lecturesand #racticals+

!ommunication

• ,ctivities involve lectures #racticals tutorials and

a eld #ractice

• Lectures - #rovide the theoretical *ac'ground of theto#ics

• Practicals - #ractical sessions in $hich /ou’ll carryout measurements and #rocess them.

• Tutorials - if there’s a need for additional guidancein the #re#aration for assessments. Please note that

/ou have to arrange an a##ointment in due time.

• "ield #ractice - a 0-day-long intensive course after

the course Surveying II.Sz. Rózsa: Surveying I. – Lecture


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Introduction

,ttendance

• Please attend all scheduled lecturesseminars and #racticals

• Please note attendance falling below !" maylead to failing t#e course irrespective of t#eacademic performance.



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!lassroom tests

• ,ltogether % classroom assessments• Practicals 1-% (1 #oints+• 2sing a theodolite 3 must #ass• Practicals 1-11 (1 #oints+• Theory (involving the to#ics of the lectures+ 34 #oints

Introduction

!ourse 5valuation

/ou’re re)uired to achieve a minimum of 67 in eachclassrom test to #ass the course.



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Introduction

Learning resources

• Some of the lecture notes are availa*le fordo$nload on the $e*site of the de#artment

htt#&&$$$.geod.*me.hu&inde89e.html

• Ho$ever /ou shall $rite o$n notes during thelectures too.

• /ou’ll *e su#lied $ith com#utational sheets eldnotes etc. during the course.

• Te8t*oo'

!. #annister $ S. Ray%ond $ R. #a&er Surveying(Seventh 5dition Prentice Hall 1004+

!ca. 1: H2"



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;e*site

Lecture notes can *e do$nloaded from

htt#&&$$$.geod.*me.hu&inde89e.html



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;e*site



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Outline

Introduction


Surveying - Science and

Profession


Levelling




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;hat is Surveying<

The art of ma'ing measurements of the relative#ositions of natural and man-made features on the5arth’s surface and the #resentation of thisinformation either gra#hically or numerically.

Since $hen<

The rst surveying $or's date *ac' to the anti)uitythe =ree' #rovided the rst account of surveyingtechni)ues.

5uclid founded the theoretical *ac'ground for

surveying *y the develo#ment of his geometry.



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5ratosthenes(ca. >6 ?!+

@S#herical 5arthA



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Outline

Introduction


Surveying - Science and Profession


Levelling




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Surveying vs. =eodesy

• in most languages there are no distinctions*et$een the terms

• in 5nglish (according to Banice' - Cra'i$s'y+

• Surveying the #ractice of #ositioning

• =eodesy the theoretical foundation ofsurveying

=eodesy is the scientic *ac'ground of

Surveying as a #rofession.



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The art of ma'ing measurements of the relative#ositions of natural and man-made features on the5arth’s surface and the #resentation of thisinformation either gra#hically or numerically.

Surveying

=eodesy

=eodesy is the disci#line that deals $ith themeasurements and re#resentation of the 5arthincluding its gravity eld in a three-dimensionaltime varying s#ace.

'eodesy (ocus on t)e *art) and neglect any %an$%ade (eatures on it +e.g. buildings, -ublic utilities,etc., /)ile surveying use t)e results o( geodesy (or

-ositioning and %a--ing o( t)ese (eatures.



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Ho$ to achieve this<

Decall the denition of Surveying

$#e art of ma'ing measurements of the relative#ositions of natural and man%made features on t#e&art#'s surface, and t#e #resentation of thisinformation eit#er grap#ically or numerically.

(et's determine t#e position )*+, +- of point +/bsolute vs 0elative positioning

A

B

X

Y

ABl

The #ositioning is usually

se#arated into horiEontal (>F+and vertical (1F+ #ositioning.

Go$adays F #ositioning can*e achieved using satellite

techni)ues too.

)*/,/-

)*,-

+

*+

+

d BP

d AP

!ontrol #oints('no$n coords

mar'ed on the eld+


?asic #rinci#les of Surveying


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(et's determine t#e position of a t#ird, un2nown point)3-.4e #ave two un2nowns5 *

+

, +

4e need two measurements5

• two distances

• one distance and an angle

• two angles

A

B

X

Y

)*/,/-

)*,-

P

d BP

d AP

d AP

α

α

β

?asic #rinci#les of Surveying

Sz. Rózsa: Surveying I. – LectureSz. Rózsa: Surveying I. – Lecture

α

β


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!lassication of Surveying

,ccording to the s#aceinvolved

• relatively small areas

• surface of earth can su##osed to*e Jat

• measurements #lotted re#resent ahoriEontal #roKection of the actualeld measurements

Gote $#e two radii can supposedto be parallel, w#en t#e l)/,- issmall.

P l a n e

S u r v

e y i n g



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!lassication of Surveying

= e o

d e t i c

S u

r v e y i n g


• large areas

• surface of the 5arth can not su##osed to *e Jat• the curvature of the 5arth is ta'en into account

ostly used (or establis)ing control net/or&s, deter%ining t)e sizeand s)a-e o( t)e *art) and deter%ining t)e gravity 0eld o( t)e *art).

Fon’t forget SiEe does matter


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n order to use t#e relative positioning, a proper number ofcontrol points are needed. $#ese points5

• are coordinated points7• are mar2ed.

Ho$ to create a country$ide coordinate system<



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!ontrol Get$or's

4#y is it necessary to #ave a common countrywidecoordinate system8

9any engineering tas2s cover a large area )#ig#ways,bridges, tunnels, c#annels, land registry, etc.-, w#ere t#ecommon coordinate system )reference system- s#ould beavailable.

$#e 3ontrol :etwor2 provide us wit# control points given int#e same refence system )coordinate system-.

$#us measuring t#e relative positions of un2nown pointsusing t#ese control points, t#e coordinates of t#e newpoints can be computed in t#e same reference system.



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The role of Surveying in !ivil 5ngineering Practice

Surveyors are needed

• to maintain the geometric order during theconstruction #rocess

;hat is this<

Laying them in the a##ro#riate geometryoutstanding structures can *e created

;rong geometry 3 the structure is not functional

• to #rovide fundamental data for the designand #lanning #rocess

• to #rovide )uantity control during theconstruction #rocess (for e8am#le earth$or')uantities+

• to monitor the structure after the construction(su*sidence deformations etc.+


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Surveying activities during the construction#rocess

?efore !onstruction 2nder construction ,fter construction

Planning anddata collection

O*servations

in the eld

Processing theo*servations

(oce+

Fra$ing ma#s#lans or #roviding

numerical data

Presentingdocumentation

to the client

Setting out on each#hase

of construction

"ield chec's of

construction

Providing dataand services to

the client

"inal (as-*uilt+#lan or ma#

on the construction

Presenting

documentationto the client


The role of Surveying in !ivil 5ngineering Practice

FeformationMonitoring&Load Tests


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Outline

Introduction



Profession


Levelling




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Nuestion 1

;hat does the height (elevation+ of a #oint mean<

Nuestion >;hat does it mean $hen #oint ? is at a higherelevation than #oint ,<

,ns$er 1The height of a #oint re#resents its energy levela*ove a reference level.

,ns$er >"or e8am#le $ater Jo$s from #oint ? to #oint ,.



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Fenition of height systems

• The #otential energy of a #oint should *e re#resented *y theheight of a #oint. Hence $ater should Jo$ from the higherelevation to$ards the lo$er elevation.

• Should have metric unit.

;hat should *e the reference of height determination<;hat is the level<

• Since the height systems should re#resent the #otentialenergy level $e need a reference surface $hich is an

e)ui#otential surface of 5arth’s gravity eld.

• The surface of calm $ater forms an e)ui#otential surface

• Mean Sea Level 3 Cronstadt (?altic Sea+ is used in Hungary(formerly Triest ,driatic Sea+.



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MSL

A

B

A H B H

&;uipotential surfaces

5)ui#otential surface (+ horiEontal surface

=ravity vector (+ vertical direction

=ravity vector is al$ays #er#endicular to the e)ui#otential surface.

g

e;uipotentialsurface



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A

B

1F #osition determination - determining the height

;e can not determine a*solute heights a*ove thereference level

Delative height determination - determining the heightdierences

Levelling *enchmar's are needed - control #oints for

$hich the elevation is 'no$n.

Re(erence level

A H

B H

A B BA H H H −=∆



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A

B

Re(erence level

A H

B H

A B BA H H H −=∆


• measuring the slo#e and slo#e distance *et$een the #oints

Levelling

α

ABl

Trigonometrical height determination

Ho$ can $e determine the height dierence<

T$o solutions

• setting a horiEontal #lane and measuring the oset from this#lane



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Outline

Introduction



Profession


Levelling




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Sz. Rózsa: Surveying I. – LectureSz. Rózsa: Surveying I. – Lecture

The #rinci#le of levelling

,

?

(l A )

(l B )

!

H AB

l A

#

l B

H AB=l

A-l B=(l

A )- !-(l B )+ #

When A= B (spherical approximation, equal distance to A and B)

H AB=(l

A )-(l

B )

t o p o g r a p h y

e q u i p o t e nt i al s u r f ac e

Line of sight


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Levelling

Over short distances the horiEontal line and level line coincide."or a distance of 1m the eect of the curvature is less than 1 mm.

The levelling device (called level+ must *e set u# so that the line of sightis #er#endicular to the gravity vector (#lum* line+. -Q the line of sight ishoriEontal.

sight of line

Horizontal

height in

Difference

staff Graduated

staff Graduated Level



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Levelling



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Outline

Introduction



Profession Methods of height determination

Levelling




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The Surveyor’s level

Tilting level

Levelling head

Tilting scre$

Fia#hragm

?u**le tu*e

Tilting a8is

!lam#ing scre$ - to 8 the telesco#e in one vertical #lane

Tangent scre$ (slo$ motion scre$+ - to nely rotate thetelesco#e along a vertical a8is

!ircular *u**le



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5lements of Surveyor’s level

Ho$ to set the line of sight to *e e8actly horiEontal<

More general ho$ to set anything to *e e8actly horiEontal<

The *u**le tu*e



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The *u**le tu*e

The radius determines the sensitivity of the *u**letu*e

R2R1

α α

R greater thanR1 2

Sensitivity ho$ much the *u**le moves due to agiven amount of inclination. The more the *u**lemoves the more sensitive the *u**le tu*e is.



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The *u**le tu*e

The determination of sensitivity

R1

α

L

l1

R1

α

L

l2

α

[ ]radians L

l l α =

−12

[ ] [ ] 8.206264" ⋅= radiansα α

basic surveying lecture 1

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