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EPS 101/271 Lecture 11: GPS Data Collection, Mapping Using GPS andUncertainties in GPS Positioning

How GPS data is collected in GeoMapperSetting Time interval for reporting GPS measurementsModes of operation and their advantagesStatic (when you stop) and dynamic modes (while you walk)

Difference of “Classroom learning” versus “Hands-experience” Using IT Technology to Determine Uncertainties in GPS data:

National Geodetic Survey Database on survey monumentsPrecision versus Accuracy: What do they really mean ?

Survey monumentsS ( d ifi )PIDS (Permanent Identifiers)

Universal Transverse Mercator (UTM) projection and the Meter

Caution: A computer and the GPS will do exactly what you tell them to do, even if it is different from what you really want- you have to be in charge and manage the digital tools

Chilean Earthquake 8.8 Richter Magnitude

Thrust fault

NY Times: Scientists Taking Steps to Defend Work on Climatehttp://www.nytimes.com/2010/03/03/science/earth/03climate.html?scp=1&sq=Climate&st=cse

Practicing Science: Based on an honor codeA chain of understanding only as good as its weakest link

You have to be there to be a participant in science

Science is about your personal priorities

Review of the USGS: COMMITTE ON SPATIAL DATA ENABLING USGSSTRATEGIC SCIENCE IN THE 21ST CENTURY

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Last

Zone 10-S

Global UTM Grid

UTM Easting

UTM Northing

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Do not start up a GPS until you are outdoors with a clear view of theSky in all directions.

Be patient until a sufficient number of satellites (4) are giving readingsWith a signal to noise ratio > 32.

Never hit the cancel button

3 useful GPS collection modes:

Static mean correctableMinimum distanceEvery time- useful in starting up

GPSGPS

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Note: Center is 60 degrees not 90

Most accurate mode to locate pointsof interest- stop at each point …Hit Restart wait at least >10 secondshit Accept, then go to next spot

Not-checked

Static mode-when you stop walking

Locate yourself, get a point on a contactPlot strike and dip

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Dynamic mapping (while you walk)

Minimum Distance

We can map contactsjust by walking them

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How GPS data is collected in GeoMapperSetting Time intervalModes of operation and their advantages

Static (when you stop) and dynamic modes (while you walk)

Using IT Technology to Determine Uncertainties in GPS data:Precision: Repeatability of measurementsAccuracy: Correctness in relation to an accepted standardAccuracy: Correctness in relation to an accepted standardWhat does “Random versus Systematic error mean ?

Geodetic Measurements

Survey monumentsPIDS (Permanent Identifier)

NGS Points Listedat Stadium

PID HT1891

Northing: 4,191,785.289Easting: 566,004.288Elev. 144.87 meters

How do we know this ?ow do we ow t s ?

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NGS DataBase

The NGS Data Sheet

1 National Geodetic Survey, Retrieval Date = FEBRUARY 27, 2004HT1891 ***********************************************************************HT1891 DESIGNATION - STADIUM AHT1891 PID - HT1891HT1891 STATE/COUNTY- CA/ALAMEDAHT1891 USGS QUAD - OAKLAND EAST (1997)HT1891 ___________________________________________________________________HT1891* NAD 83(1992)- 37 52 16.16975(N) 122 14 58.33062(W) ADJUSTED HT1891* NAVD 88 - 144.87 (+/-2cm) 475.3 (feet) VERTCON HT1891 ___________________________________________________________________HT1891 EPOCH DATE - 1991.35HT1891 LAPLACE CORR- 3.66 (seconds) DEFLEC99HT1891 GEOID HEIGHT- -32.22 (meters) GEOID03HT1891HT1891 HORZ ORDER - FIRSTHT1891 VERT ORDER - FIRST CLASS I (See Below)HT1891HT1891; North East Units Scale Factor Converg.HT1891;UTM 10 - 4,191,785.289 566,004.288 MT 0.99965366 +0 27 38.6

What does GPS data for the same spot look like over time?

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Accuracy:relative to a known

GPS measurements remainingin the same location

geo-spatialstandard

Systematic errors:Displaced from the standard

Definition of the Meter as 1/107 the distance between the equator and the north pole- about the time of the French Revolution

1791- an effort to standardize units of measure- wrt “nature”

Astronomers: Jean-Baptiste Delambre and Pierre MechanEarlier measurement by Eratosthenes ( 276-195BC) of circumference

f th th t ithi f % f t d t i h d

Latitude is 37 degrees, 52 minutes, 16 secs or 37.87 decimal degrees.Fraction of latitude north of the equator = 37.87/ 90 degrees=0.4208Predict the Northing in UTM coordinates:

Mean radius of the “spherical” earth = 6 37 x 106 meters

of the earth to within a few % of current data using shadowlength in Alexandria during summer solstice

Mean radius of the spherical earth 6.37 x 10 metersCircumference = 2r=4.0x106 meters= 40,000,036 mEquator to Pole = Circumference/4 = 1.0 0x107 meters

Predicted UTM Northing= 0.4208 x 1x106 meters=4,208,000 N meters vs actual 4,191,785.289Difference is 16 km = 0.38%

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Radio Waves

19 cm

1/2 wavelength GPS Patch ceramic plate antenna

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AOR-WPOR

HGOP =1 is ideal

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Remember:

Wait until the hard drive indicator stops before doing anythingTurn off back lighting out doors to save battery lifeTurn off bell sounds to save battery

Take care of the computer, GPS, pen and spare battery now in your charge- no room for a “shaggy dog story”

While traveling, Put PC’s in box case or in your own personalcare in your lap

When leaving lab, make sure zippers are closed after changing batteries so they don’t fall out

th don the groundSave your work using red Save ButtonUse red Exit button to exit GeoMapper

Lockers:

Each night:

Hang computer with screen towards the right on the hook on the right sideof your locker

Partially unzip the case and plug in the power cord and check displayto make sure it is in fact on charge

Plug extra battery onto the charger nearby on the desk top

Put your padlock through the hole from the right side

Make sure that the locker door is closed securely

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Liability Acceptance and Honor Code Agreement For Use of Pen Computers

Care of pen computer: Using portable pen computers in the lab and the field require that they be treated with respect and handled accordingly atall times even when driving to and from the field They are fragileall times even when driving to and from the field. They are fragileinstruments. They cannot be just put in the back of the truck, but shouldbe carried by each student or put in the box provided being careful that no damage occurs to the screens. Once a computer is assigned to astudent team it is under their care until it is signed back in at the end ofthe course. Lockers are provided for each computer and a key is assigned to each student. After returning from the field, a used batteryassigned to each student. After returning from the field, a used battery must be returned to the battery charger docking station and the computerhung on the right side of the locker and its charging cord plugged in sothe main battery is charged ready for the next use. To plug in the cord, the black field case is unzipped partially.

Be careful to zip up the case so the computer does not fall out when leaving for the field. Be careful when you take the computer from the locker not to drop the computer. Besides the mapping file with your name on it and assigned to you below, No other files or programs can be put on this computer.Student mapping files are propriety to the students making them and toStude t app g es a e p op ety to t e stude ts a g t e a d tothe instructor and should not be open by any other student. All existing map files, quizzes, and past report are off limits to all EPS 101/271 students. All sources of information must be acknowledged inyour reference list of your report. The PC tablets computers are to beused only for this class as designated by the instructor. Room 345 isto be used only with the Professor’s permission.

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I accept financial liability to cover the costs of repairs of the pen computer assigned to me either because of negligence or accidents while under my care and agree to all conditions above. A lost computer is $ 2435, Battery is $ 178, case $ 128, stylus $ 30 and a GPS unit is$ 78. Damaged computers can cost as much as $ 350 to repair and will mean mapping on paper while the tablet is being repaired.

I accept financial responsibility for the pen computer and promise to obey the use codes above

Computer Open berkhills map and Save As:# Signature # 1 Student # 2 Map file name be2010flfl

2 ____________________ ______________________ ______________________________3 ____________________ ______________________ ______________________________4 ____________________ ______________________ ______________________________5 ____________________ ______________________ ______________________________6 ____________________ ______________________ ______________________________7 ____________________ ______________________ ______________________________

I do not accept financial responsibility and will use only the map boardName:_______________________________________________________________

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Prepare the base map each team will use:

Go to lockers and bring pen tablet back to this room

Teams of 2 people- share one PC tablet (10 PC’s in all)Each tablet will be with a green mapping vest

Do this together in unison

Open GeoMapperGo to EPS 101 directory Green Start Mapping buttonWait until you see the GeoMapper icon interfaceBlue Select Base ButtonVector box, select “berk” fileOK then Yes twiceFile Save As: be10flf.pts

where f = first initial; l =1st letter of last name

More …..

Mapping in the Siesta Valley Formation using DM Systems

Purpose:Use of GPS to maplacustrine bedslacustrine beds

Meet up at Strawberry Canyon

Take pen tabletExtra battery

Meet up at Strawberry Canyon

Park