the traverse lab ©2010, adjusted 2011 dr. b. c. paul note – the techniques shown in these slides...

The Traverse Lab

©2010, adjusted 2011 Dr. B. C. PaulNote – The techniques shown in these slides are considered common

knowledge to surveyors. Figures in the slides may be the authors own work or extracted from Instrument Users Manuals, Surveying by

Bouchard, Mine Surveying, or various internet image sources.

The Traverse Traverses carry a known point and

direction forward to other points Common Problem in Surveying is that

readings are taken “line of sight” Traditional instruments “line of sight” means

visible light seen by human eye EDMs or GPS systems use beams of

electromagnetic radiation out of human eye range

Still depends on line of sight Line of Sight Problem and Triangulation

Usually can’t just set up a baseline and shoot in everything you want to

The Traverse Technique

Start with a known pointAnd line of known direction

Turn the Angle Right to Your Foresight

Measure the Angle to the right

Backsight Az + Angle Right = Foresight Az.

Measure Distance

Distance and direction will allow point to beCalculated.

Now I Move My Instrument and Occupy Point B

A

B

C

Now I Move My Instrument to Point C

A

B

C

D

Traverse Procedures and Variations Can see the technique can carry control around

obstacles and over distances too great to shoot in one shot

Common variation is to survey around a loop coming back to the point of beginning

Called a closed traverse Closing Traverse checks for errors

When you get back to your starting point you better have the same coordinates within a close tolerance or you screwed up (big errors called busts)

Minor field variations are inevitable – there are adjustment procedures for doctoring up minor distributed errors

Obviously an open traverse lacks this ability unless it ends at a point of known coordinates

Field Notes Traditional surveyors have had a note

book in which they record the measurements

Some new instruments record things digitally – but software is very specific

This class have to use an Exel spreadsheet form Suggest you run it on a laptop or tablet It will do calculations for you in the field

The Mandatory Spreadsheet

Traverse Form

You must input the name you choose for a pointYou put this information in from other forms or initial given informationYou measure this and put it inIntermediate Calculated FieldMajor Answer Output

Explain what you are doing with this shot.

Information You Must Collect And Enter.

Information you need for a point where you set up your

Instrument

Where Are You Setting Up Your Instrument? A

What are the Coordinates of This Point? Northing 0 Easting 0 Elevation 0

Measure the Height of Your InstrumentEnter the Height of Your Instrument in feet and tenths (ie 5.1 would be 5.1 feet) 4.1

If You have a tape in feet and inches Enter feet Enter inches

What Are You Backsighting? BS1

What is the direction to this backsight? Degrees 10 Minutes 10 Seconds 15

Aime Your Telescope at Your Backsight and Make Sure the Horizontal Angle Reads 0

Use one copy ofForm for eachInstrument set-upAnd shot

Orange, Pink, andYellow are fieldsYou must fill in(I have had problemsWith people notRecording neededInfo in the past)

The Color Code

Orange is the names you give to points you site

Yellow is a measurement you must take and record while surveying

Pink is for information that you either have given to you or calculate from earlier traverse shots

The Answer Colors

Green is for a calculation the spreadsheet does

Red is for an Answer Spreadsheet has calculation

formulas here – don’t mess with them unless you know what you are doing.

Using the SpreadsheetExplain what you are doing with this shot.Starting a traverse by setting up at the known point and back sighting a known line of site and forsighting the first point to figure for my traverse.



Instrument


What are the Coordinates of This Point? Northing 381288 Easting 2570639 Elevation 448.31

Measure the Height of Your InstrumentEnter the Height of Your Instrument in feet and tenths (ie 5.1 would be 5.1 feet)If You have a tape in feet and inches Enter feet Enter inches

What Are You Backsighting? Smoke Stack

What is the direction to this backsight? Degrees 57 Minutes 13 Seconds 45.12

We start out ourTraverse at point A(we just happen toKnow the coordinates)

We set up ourInstrument there andEnter this information

Starting Our TraverseExplain what you are doing with this shot.Starting a traverse by setting up at the known point and back sighting a known line of site and forsighting the first point to figure for my traverse.



Instrument




What Are You Backsighting? Smoke Stack

What is the direction to this backsight? Degrees 57 Minutes 13 Seconds 45.12

We backsight theCenter of the centerSmall stack on thePower plant smokeStack

We report our back-Sight and enter the known direction of the line.

What I Will Do From the known point and known

backsight direction I will turn an angle to my first chosen

point of the traverse (I will measure the angle I turned) (And the distance to the point) My spreadsheet will tell me what direction

the point is in and what its coordinates are (The spreadsheet will do all the Trig for me)

Of course I still have stuff I must fill in.

I need to measure the height ofMy instrument

Measure from the ground upTo the point at the center ofYour telescope.

Enter The Information in Your Spreadsheet


Instrument




Your tape may be in feet and inches or in feet and tenths of feet. Enter oneOr the other.

Enter Your Height of Instrument

Measure the Height of Your InstrumentEnter the Height of Your Instrument in feet and tenths (ie 5.1 would be 5.1 feet) 4.5


Suppose I Measure 4.5 feet.

Enter the Name of the First Point You Choose for Your Traverse.

Turning the Angle to the Right Aime the Telescope at Your Foresight Point

What is the name of your Foresight Point? FS1

In this example I name my first foresight FS1. You will probably call itSomething more like B or 2 (since this will likely be the next place you moveYour instrument to).

Next You Need to Report the Angle You Turned to the Right

Read the Horizontal Angle to the Right.Put in 1 for the Way Your Instrument Measures the Angle. Then Put in the Angle

My Instrument Measures in Degrees Minutes and Seconds 1 Degrees Minutes Seconds

My Instrument Measures in Mills. Mills

My Instrument Measures in Gons or Grads Gon Reading

You need to indicate what units your instrument measures angles in

Degrees Minutes Seconds – Put 1 here

Mills - Put 1 here

Gons – Put 1 here

Next You Put In the Measure


My Instrument Measures in Degrees Minutes and Seconds Degrees Minutes Seconds


My Instrument Measures in Gons or Grads 1 Gon Reading 127.1474

This is a Gon example – note the measure is inDecimal Gons.


My Instrument Measures in Degrees Minutes and Seconds 1 Degrees 97 Minutes 30 Seconds 0



This illustrates input in degrees minutes seconds.

Now I Need to Record the Vertical Angle

Read the Verticle Angle on your instrument.Put in 1 for where your instrument has 0 for the verticle angle. Then put in the Angle

My Instrument measures 0 when the telescope is shooting straight up 1

My Instrument Measures in Degrees Minutes and Seconds 1 Degrees 88 Minutes 10 Seconds 0

My Instrument Measures in Mills. Mill Reading


My Instrument measures 0 when the telescope is shooting levelMy Instrument Measures in Degrees Minutes and Seconds Degrees Minutes Seconds

My Instrument Measures in Mills. Millings


First thing I record is whether the scope reads 0 points straight up or0 pointing exactly horizontal (except for older transits most instrumentsWill probably read 0 straight up).

If it does read 0 exactly to the horizontal put 1 in here.

Now I Need to Indicate Whether I Measure in DMS, Gons, or Mills

Read the Verticle Angle on your instrument.Put in 1 for where your instrument has 0 for the verticle angle. Then put in the Angle

My Instrument measures 0 when the telescope is shooting straight up 1

My Instrument Measures in Degrees Minutes and Seconds Degrees Minutes Seconds

My Instrument Measures in Mills. 1 Mill Reading 1590


My Instrument measures 0 when the telescope is shooting levelMy Instrument Measures in Degrees Minutes and Seconds Degrees Minutes Seconds

My Instrument Measures in Mills. Millings


This example is for a Mill Instrument that measures a zenith angle.

I Now Consider How Far Away My Next Point Is

Decide whether you are aiming at a stadia rod or aiming at a reflector with an EDM Enter 1 for what you are doingThen indicate the measurements

I am aiming at a reflector and taking an EDM Reading 1 Distance 205.7

Measure the Height of the Reflector above the ground with Your Tape MeasureEnter the Height of Your Refector in feet and tenths (ie 5.1 would be 5.1 feet) 3.5


I am aiming at a stadia rod and taking rod readings Upper Middle Lower

I will be measuring distance by shooting with an EDM or shooting Stadia

Enter 1 here if you are using an EDM

Enter 1 here if you are shooting stadia

If I Am Using An EDM

I am aiming at a reflector and taking an EDM Reading 1 Distance 205.7

Measure the Height of the Reflector above the ground with Your Tape MeasureEnter the Height of Your Refector in feet and tenths (ie 5.1 would be 5.1 feet) 3.5


My Distance will read out in decimal feet. (Most EDMs also measure in meters butYou can set that on the instrument and in this class we will be using feet).

Reflector HeightIf you aimed here

Measure the height here

Again you must decide whether you have feet andInches or decimal feet.

Enter the Height of Your Refector in feet and tenths (ie 5.1 would be 5.1 feet) 3.5


Note you simply enter which everYou have.

If You Are Shooting Stadia

I am aiming at a stadia rod and taking rod readings 1 Upper 5.2 Middle 4.2 Lower 3.2

Enter 1 to indicateStadia

Then Enter the Upper, Middle, and Lower Rod Readings.

Make Sure Each Sheet Explains What You Did

Explain what you are doing with this shot.Starting a traverse by setting up at the known point and back sighting a known line of site and forsighting the first point to figure for my traverse.



Instrument

In starting my traverse I set up at a known point, backsight a known direction,Turn the angle to the next point of interest, measure the angle, measure the Distance, and calculate the direction to that next point and its coordinates.

Only In This Case the Spreadsheet Does the Trig for You

Important things – I have the coordinates of my foresight point (I can use thisTo plot its location on a map).

It also tells me that if I move my instrument to that Foresight point and thenBacksight where I am now it gives me the direction of that line.

Major Resultsnorth east elevation

The Coordinates of the Foresight Point FS1 Are 381107.14 2570724 450.5735

The Distance to Your Foresight Point FS1 Is 200 Feet

degrees minutes seconds

The Direction to Your Foresight Point FS1 Is 154 43 45.12

If you Move Your Instrument to Your Foresight Point and then use your present station as a backsightThe Direction of Your New Backsight Line Will Be


334 43 45.12

I Move Foreward to My Old Foresight Point and Backsight my Old Instrument Station My first spreadsheet gave me info I

will need For my very first point I relied on

someone else to give me the coordinates

When I move forward to my old Foresight point I have calculated the coordinates myselfnorth east elevation

381107.14 2570724 450.5735

Start Filling Out My Next Form

Explain what you are doing with this shot.Move to FS1, backsight my original point, and then pick the next foresight point of the traverse.



Instrument

Where Are You Setting Up Your Instrument? FS1

What are the Coordinates of This Point? Northing Easting Elevation


What Are You Backsighting? A

What is the direction to this backsight? Degrees Minutes Seconds

Aime Your Telescope at Your Backsight and Make Sure the Horizontal Angle Reads 0

Where do I get theCoordinates of FS1?

north east elevation

381107.14 2570724 450.5735

Moving on to the Known Direction

Where Are You Setting Up Your Instrument? FS1

What are the Coordinates of This Point? Northing 381107.14 Easting 2570724 Elevation 450.5735


What Are You Backsighting? A

What is the direction to this backsight? Degrees Minutes Seconds

Where do I get the backsight direction?If you Move Your Instrument to Your Foresight Point and then use your present station as a backsightThe Direction of Your New Backsight Line Will Be


334 43 45.12

Why Have a Tablet/Smartphone or Laptop in the Field

If you can run the Excel sheet in the field you will get your answers as you go. If your Smartphone can run excel you can use

the Smartphone as your tablet. If you don’t have a field computing

device then fill in the form except the pink fields and then you’ll have to transcribe data from paper to Excel files in the computer lab.

The Problem of Occupying Points

Traversing is good way to bring in control and dodge obstacles Could get to be a real pain if had to occupy

every point of interest Might be doing a property boundary

survey Property corners are key points but they

might be lousy points to set up as a station Can shoot in side points from off the

traverse

Example – Suppose You Were trying to get coordinates corner of the Engineering Building

Can’t set up an instrument inside a brick wall

0,0,0

N

You may take some side shots

Side Shot

Backsight

KnownInitial point

How Do You Handle Side Shots With the Spreadsheet

Just like any other point except you never occupy the “Foresight” point when you take a side shot The coordinates of the “Foresight” in

a side shot will be used to plot points on the map

You will not need to worry about the direction.

Your First Field Lab is a Traverse Around the Engineering or other Building

One Team goes one way. Another the other.

0,0,0

N

Your Work

Shoot in all the major corners of the building and the courtyard

As teams converge they will shoot in a common foresight point

The coordinates you have for that point should agree

One Special Task

A and D wing Areas

E Wing of BuildingParkingLot

A Grate

Side Shoot in the Grate

Get the coordinates of these twoPoints with side shots

Don’t Do This

A

B

C

D

E

F

F1

F2

Remember to Close Your Traverse

This will be done either by traversing back to point A

Or by both teams going around the building sighting and getting coordinates for a common meeting point.

Doing Your Lab Work The class has a folder on the Mining

Department Server. Everyone has a subfolder under the class Everyone can see your subfolder, but only you have

write privileges. Within 1 day of the lab you must have all your

traverse worksheets done You must do a MineSight drawing showing your

points and the coordinates T.A.s will check you off a day later – if you did not do

the plot work you don’t get credit for that day at class

The Traverse

Your traverse will likely take 2 or 3 class periods.

At the end you will make a map combining everyones work You will have 1 week after the field

work is done to compile your complete map.

Assigned Survey Targets

Engineering Building South Side Engineering Building North Side Ag Building Neckers Communications Two dorms of choice at Thompson

Point

the traverse lab ©2010, adjusted 2011 dr. b. c. paul note – the techniques shown in these slides...

Documents

point awe

point of beginningcalled

chosen point

point babcnow

starting point

known backsight directioni

line of sightline

open traverse