Traverse

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Florence A. GaleonAssistant Professor

U.P. College of Engineering

Outline

I. IntroductionII. Types of Traverse

Survey Party CompositionIII. Survey Party CompositionIV. Instruments / AccessoriesV. Traverse AdjustmentVI. Methods of Traverse AdjustmentVII. Sample Problem

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Introduction

n The relative location of points in a horizontal plane are determined by measurements from control points and control lines called

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control points and control lines called horizontal control.

Traversing and Triangulation

n In the establishment of horizontal control, traversing and triangulation are the two methods commonly used.

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Triangulation Network

n In plane surveying, the establishment of horizontal control usually consists of a traverse.

n A traverse consists of a series of straight lines, the lengths and directions of which are determined,

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lengths and directions of which are determined, connecting successive established points along the route of a survey.

n The traverse is most satisfactory for surveys of limited extent such as providing basic horizontal control for land, route, construction surveys, etc.

Types of Traverse

I. Closed Traverse

It is a traverse that starts and terminates at a station of known position.

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Two Types

1. Loop Traverse – starts on a station of known position and terminates on the same station

2. Connecting Traverse - starts on a station of known position and terminates on a different station of known position

Types of Traverse

II. Open Traverse

It is a traverse that starts on a station of known position and terminates at a station of unknown position.

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and terminates at a station of unknown position.

Loop TraverseOpen Traverse & Connecting Traverse

Survey party composition:

1. Instrument man

He directs the survey party, operates and cares for the instrument, and keeps the notes.

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Survey party composition:

2. Rodman

He gives sights as directed by the instrument man.

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Survey party composition:

3. Utility menThey are employed to clear the lines of any

obstruction and may perform other duties as directed by the chief of party.

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Axe & Bolo

Some Utility Men

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Survey party composition:

4. RecorderWhere many observations are taken, the notes

are kept by this member and may also act as the chief of the party.

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chief of the party.

Instruments / Accessories:

1. Total Station / Smart Station2. Engineer's Transit / Theodolite3. Tape / EDM / Laser Range Finders

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3. Tape / EDM / Laser Range Finders4. GPS Receivers5. Rods / Range Poles / Reflectors6. Chaining Pins / Markers7. Two-way Radios

Rods

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Range Poles & Prism

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Two-way Radios

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departure

latit

ude

Traverse Adjustment

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latit

ude

L

θ

Traverse Adjustments

n Latitude of a line – is its projection on a north-south line

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latitude = L x cosθ

Latitude of line going north is positiveLatitude of line going south is negative

+

-

Traverse Adjustments

n Departure of a line – is its projection on aneast-west line

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departure = L x sinθ

Departure of line going east is positiveDeparture of line going west is negative

+

-

Plotting a Closed Traverse

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LECCL

CD

n Linear Error of Closure = √CL²+ CD²

where CL = total error in latitudeC = total error in departure

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CD = total error in departure

n Relative Error of ClosureREC = LEC = 1

D D / LEC

Methods of Traverse Adjustment

1. Compass Rule

Cl = d x CL Cd = d x CD

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Cl = d x CL Cd = d x CDD D

where Cl = correction in latitude for each lineCd = correction in departure for each lined = distance of each line

D = total distance of the traverse lines

Methods of Traverse Adjustment

2. Transit Rule

Cl = lat x CL Cd = dep x CD

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LAT DEP

where: lat = latitude of each linedep = departure of each line

LAT = total latitude of the traverse lines DEP = total departure of the traverse lines

Sample Problem

Balance by the Compass Rule the data tabulated below. Also determine the relative error of closure, the corrected length and corrected bearing of each line.

LINE LENGTH BEARING

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LINE LENGTH BEARING

1-2 80.11 m N 53°54’ E2-3 69.44 S 01°37’ E3-4 56.19 S 80°10’ E4-5 105.83 S 53°33’ W5-1 103.00 N 21°34’ W

Tabulated Solution

LINE LENGTH BEARING LAT DEPCORRECTIONS ADJ

LATADJ DEP

ADJLENGTH

ADJBEARINGLAT DEP

1-2

2-3

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2-3

3-4

4-5

5-1

Σ = D Σ = ±CL Σ = ±CD Σ =CL Σ = CD Σ = 0 Σ = 0

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