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Vertical Distance

Measurement

ERE 371:

Surveying for

Engineers

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Introduction

Surveying based on measuring to !uantities

Measurement of linear distances

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Slo"e Distance

#

S$#$

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%ori&ontal Distance

$

#

%$#

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Vertical Distance

$

#

V$#

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Introduction

Vertical distance measurement ' (leveling)

Includes "rocedures t*at determine

$

#

V$#

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Revie Ideas and Definitions

Vertical line

+evel surface ,line-

%ori&ontal "lane ,line- Vertical datum

Elevation

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Met*ods

.raditional met*ods to determine elevation c*anges

Recent a""roac*es

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.a"ing

/rocess

$""lications

Modern variations

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#arometric +eveling

$tmos"*eric "ressure varies inversely it* elevation

0*allenges

$""lication

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.rigonometric +eveling

0om"ute difference in elevation by measuring

Measurements re!uired

$""lication

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0once"t of .rigonometric +eveling

#ased on solution of rig*t triangle

%

SV

$#

0

%tanVorSsinV ==

Velevelev $0 +=

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$

#

Real .rigonometric +eveling

2no elevation of $: ant to find elevation of #

$s before: V ' S sin

%ere *i ' $D and r ' #0

elev#' elev$ *i V 4 r

0

E

D

SV

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$""lying .rigonometric +eveling

0onsider line lengt*

5 S*ort lines ,6 1888 ft-

5 +onger lines

Im"roving accuracy: reci"rocal measurements

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9/S +eveling

Modern 9/S "rovides 3D location

.raditional differential leveling considers gravity

0oncern

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9eoid4Elli"soid Relations*i"

Mean Sea +evel

,9eoid-

Elli"soid .errain

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0onverting %eig*ts

0onversions beteen elli"soid *eig*ts and elevations

Determining geoid *eig*t ,-

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Differential +eveling

;sage

9eneral conce"t

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.*eory of +eveling

$:

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$dditional Ideas and Definitions

#enc*mar< ,#M-

0onsiderations

Mean Sea +evel ,MS+-

+eveling

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$dditional Ideas and Definitions

ational 9eodetic Vertical Datum of 1=>= ,9VD>=-

5 ?irst national datum establis*ed

5 $d@ustment of 188A888

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Eart* 0urvature

Eart* curvature*ori&ontal lines level lines

Im"act

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Eart* 0urvature

%ori&ontal +ine

+evel surface

Vertical line

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$tmos"*eric Refraction

$tmos"*eric refraction*ori&ontal lines level lines

Im"act

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$tmos"*eric Refraction

%ori&ontal +ine

+ine of sig*t

,refracted-

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0ombining Effects

%ori&ontal +ine

+evel surface

0ombined

effect

Refracted +ine

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Readings

0*a"ter F: Section 1 5 1F

0*a"ter =: Section

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Differential +eveling E!ui"ment

?undamentally to ty"es of e!ui"ment

5 +evel

5 9raduated rod

E!ui"ment variation

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.y"es of levels

5 %and levels

5 Dum"y G Hye levels

5 Digital levels

5 Electronic laser levels

5 .ilting levels

5 $utomatic levels

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+eveling Instruments

Dum"y levels

$utomatic levels

+evelot +evel

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+eveling Instruments

.ilting levels

#efore 0oincidence $fter 0oincidence

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Rods

5 Made of oodA fiberglass or metal

5 9raduated in decimal feet or decimal meters

.y"es of rods5 /*iladel"*ia rod

5 Metric rod

5 Digital rod

5 /recision rod

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Differential +eveling Measurements

Establis*ing *ori&ontal "lane

Measuring vertical distances

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.*eory of +eveling

#ac

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#ac

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Side Vie

elev$' 183F=m

Datum: elev ' 8888m

%I ' 18FF=Cm

#S ,-1837m

?S ,4-8B=m

elev#' 183C81m

Elev#' Elev$ #S 4 ?S

Elev$ #S ' %I %I 5 ?S ' Elev#

$:

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J"erations in Differential +eveling

0annot usually determine elevation it* one setu"

Establis* turning "oints ,./s- and re"eat basic "rocess

5 ./ c*aracteristics

5 0reate line of levels

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Differential +eveling Eam"le

#M $

,elev

13FCBm-

#

18m

./1

1F1m

8=>7m

./>

1>=m

8713m 1B3m

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Differential +eveling ?ield #oo7m 1F1m 13F>B=m

13>1Cm

./ > 8713m 1>=m 133=>1m

13FC3Fm# 1B3m 13>7==m

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13>1Cm

./ > 8713m 1>=m 133=>1m13FC3Fm

# 17Cm 1B3m 13>7==m

13Fm

./ 3 133m 8=17m 133C3Bm

13171m./ F 13BFm 8BF1m 13F338m

1371Fm

#M $ 18>7m 13FCB7m

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0losure

9eneral conce"t

+evel loo" closure

Met*ods: end on

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+evel +oo" 0losure

0om"ute closure based on end"oint

Define alloable closure

0om"are field closure to alloable closure

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13>1Cm

./ > 8713m 1>=m 133=>1m

13FC3Fm

# 17Cm 1B3m 13>7==m13Fm

./ 3 133m 8=17m 133C3Bm

13171m

./ F 13BFm 8BF1m 13F338m

1371Fm

#M $ 18>>m 13FC=>m

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/age 0*ec

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/age 0*ecm

/oint Elev 0orrection 0orrected Elev

#M $ 13FCBm 13FCBm

./ 1 13F>B=m 48881 m 13F>BBm

./ > 133=>1m 4888> m 133=1=m

# 13>7==m 4888F m 13>7=m

./ 3 133C3Bm 4888 m 133C33m

./ F 13F338m 4888C m 13F3>Fm

#M $ 13FC=>m 48887 m 13FCBm

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/rofile +eveling

/rocess

Variation of differential leveling

Issues

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/rofile +eveling

888

#M 1

./ 1

./ >

./ 3

.urning "oints

Instrument location

#enc*mar

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