gps and gis

Use of Handheld GPS Equipment (Garmin 72, Garmin 76 or Garmin Venture Garmin Etrex,etc)Data Transfer to Office ComputerGIS-Reproduction and Appearance on digital Topo-Maps and Plans

Practical Introduction to Handheld GPS and GIS

8/6/2008 - University Advisor Jan-Peter Mund (PhD Geographer) 2

Objectives of the training (1)1. Practical training on handling of

Global positioning system measurements (GPS)

2. Transmission and teaching of general information about GPS

3. Opportunities and Facilities of handheld GPS4. Practical GPS measurements in the field in

relation to field survey tasks5. Transfer GPS-Data to Desktop-GIS (ArcView)


Repetition: The absolute location

North pole

Greenwich, UKZero-Meridian

orPrime Meridian= 0°Longitude

Equator= 0° Latitude

Absolute location= W 92° 24‘’56.4“

Longitudeand North

34° 26’21.6“


What is a map in general ?

A map is a graphic representation of selected geographic features represented on a plane surface

Maps are essentially models of the Earth’s surface

Maps always have limitations - they are never completely accurate, and they are always incomplete

Maps may misrepresent information or deceive the user (either deliberately or accidentally)


What is the appropriate planning scale ?

The appropriate planning scale depend on the objective, the objects and the available scale of the base data.

That means, that you can not easily up- or down scale your data until it fits to the required scale.

Try to avoid down scaling of base data or maps, i.e. from 1: 25.000 to 1: 10.000.

You can up scale or generalize or your data as much as you like but with generalization you will loose information of the data.

An appropriate planning scale for urban environment is between 1: 1.000 to 1: 15.000.


How to measure on a round Earth ?

Measurement to know !

1 Degree Latitude ~111 km

1 Degree Longitude~111 km at Equator

and up to0 km at Poles= longitude convergence


Geographic CoordinatesLatitude, Longitude, & Ellipsoidal HeightLatitude & Longitude are defined by the Prime

Meridian and the Equatorial reference planes

Geographic latitude Vertical angle fromthe equator to the normal of ellipsoid, positive in Northern Hemisphere andnegative in the southern

Geographic longitude Horizontal angle from the prime meridian positive in the eastern hemisphereand negative in the western

Geodetic height Distance normalfrom the reference ellipsoid

Observer’sMeridian

PrimeMeridian

Latitude

Longitude

Y

Z

XLat- lonN 11°32’54,6“E 104° 55‘’36,0“


Rules of Thumb for Latitude Longitude

Rules of thumb for latitude• 1º Degree latitude ≅ 60 nautical miles (≅ 111km)

• 1’ Minute latitude ≅ 1 nautical mile (1,853 km)

• 1” Second latitude ≅ 30 meters

• 0.1” 1/10 second latitude ≅ 3 meters

• 0.01” 1/100 second latitude ≅ 30 centimeters

Rules of thumb for longitude• Don’t forget longitude convergence

• Don’t forget the base 60 conversion

• 60 minutes per degree

• 60 seconds per minute


• Projecting the sphere onto a cylinder tangent to a central meridian.

• Distortion of scale, distance, direction and area increase away from the central meridian.

• If you rotate the cylinder every 6º of longitude you create the UTM projection.

• This projection is used on map scales of 1:500,000 and larger

UTM-Projection


Cylindrical ProjectionsUTM Projection and Coordinates:• Flat Grid extending from 84N to 80S• Each zone is numbered Eastward starting at 177°W (6°

wide from 180°W to 174°W)• Coordinates are read east then north• Many map products from foreign countries use UTMs


Projection PropertiesConformalShapes are maintained on the map as they are on the globe. Angles are preserved

Equal AreaMaps cannot simultaneously show shape and area accurately. Area of all features on the map have the same relative proportions and size as they do on the globe.

EquidistantScale stays the same across the entire map sheet.

So equal-area maps show only area accurately and conformal maps show only the shape accurately. Compromise Maps: Show neither area nor shape completely accurately


Global Positioning System (GPS)

GarminEtrex VentureHandheld Outdoor 12 Band Reciever

Garmin GPS 72Handheld Personal Navigator 12 Band Reciever

Introduction to handle two different handheld GPS – ReceiverGarmin 72 and Garmin eTrex Venture



GarminEtrex VentureHandheld Outdoor 12 Band Reciever

Garmin GPS 72Handheld Personal Navigator 12 Band Reciever


History/Development (USA, Russia, EU, Selective Availability)

Elements (Satellites, Receivers Correction / Ground Control)

Function (Distance Measurement, No. of necessary Satellites)

Sources of Error – Selective Accuracy

Improvement of Accuracy - DGPS/WAAS



Global Positioning Systems (GPS)


Garmin GPS Handbooks


Button Functions of eTrex Venture


Turning on the eTRex Venture

Two welcome Pages appear first,you can skip them with the

PAGE-Button

Two switch on the device please press the

ON/OFF buttonmin. 2 seconds

and than...

The joystick to switch themenu is on the front


Turning on the Garmin GPS 72

A welcome Page appear first,you can skip them with the

PAGE-Button

Two switch on the device please press the

ON/OFF buttonmin. 2 seconds

and than...


How to hold the Receiver ? What to consider for best Accuracy?


Indoor or Outdoor ?


The Main Basic Pages


PAGE-Button

Shift Main Pages: 2 Ways


MAIN Menu


MAIN MAIN PagesPages SETUP SETUP UNITSUNITS::!!!! CheckCheck !!!! -- MapMap DatumDatum!!!! CheckCheck !!!! -- ProjectionProjection

Same Position with different Map Datum:

Indian/Thailand: 48P 0489613 1272328

WGS 84: 48P 0489190 1272647

Question:

How far they are away from each other ifused on the same map?


MAIN Pages SETUP HEADING:

!! Check !! North Settings


MAIN Pages SETUP SYSTEM:!! Check !! GPS, WAAS


3 Main Elements:

- Waypoint /Go to (Find),

- Track,- Route


Mark Waypoint

Press Press and holdand hold Thumb Stick Thumb Stick until MARK Page appearsuntil MARK Page appears


Edit Waypoint

SwitchSwitchwithwithThumbThumb--StickStickthroughthroughthethefieldsfields, , press press „„EnterEnter““wherewhereyouyou wantwantto to changechange..


Find / Go to


Tracks


Track Log Setup


Trip Computer and Reset


This is not a Compass !!!


Press ON-Button for~ 2 sec.Until GPS turns off

(… and if you press onlyshortly, than it´s for thelight!)

Turning off the GPS

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