Presentation on theme: "PRACTICAL GPS APPLICATIONS IN FORESTRY & AGRICULTURE. MIKE CLIFFORD"— Presentation transcript:
1 PRACTICAL GPS APPLICATIONS IN FORESTRY & AGRICULTURE. MIKE CLIFFORD PRACTICAL GPS APPLICATIONS IN FORESTRY & AGRICULTURE MIKE CLIFFORD VIRGINIA COOPERATIVE EXTENSION
2 PRACTICAL GPS APPLICATIONS IN FORESTRY & AGRICULTURE Workshop & Field TestsIntroductions; Workshop & Field Testing ObjectivesBasics of the Global Positioning System.Features and operations of GPS receivers – Garmin eTrex series & others.Digital topographic maps - MapTech Terrain Navigator & Garmin Mapsource.Transfer of waypoints, tracks (area perimeter), and routes (cruise lines & plots).Set up cruise lines on Terrain Navigator and GPS units. Test in the field.Use GPS to calculate area in the field and compare results to1. Traditional methods2. Terrain Navigator's area calculation figures3. Post-collection DGPS figures.Discuss available sources and resources.Evaluation and follow-up.
3 GPS and GIS DEFINITIONS GPS is short for Global Positioning System which is"a network of satellites that continuously transmit coded information, which makes it possible to precisely identify locations on earth by measuring distance from the satellites".Of course, many users also refer to their hand-held GPS receivers as "my GPS" ... as in the statement "my GPS'batteries went dead and I got lost!"GIS is short for Geographic Information System(s). "In the strictest sense, a GIS is a computer system capable of assembling, storing, manipulating, and displaying geographically referenced information , i.e. data identified according to their locations. Practitioners also regard the total GIS as including operating personnel and the data that go into the system"( from: ).
4 PROVIDED BY GPS RECEIVERS . . . BASIC INFORMATIONPROVIDED BY GPS RECEIVERS . . .YOUR CURRENT POSITIONCOORDINATES (LATITUDE & LONGITUDE, UTM, MGRS, ETC.)ELEVATION (APPROXIMATE)DIRECTION TO SPECIFIED WAYPOINTS (“MARKERS”)(0R BETWEEN WAYPOINTS)DISTANCE TO SPECIFIED WAYPOINTSYOUR SPEED OF TRAVELYOUR DIRECTION OF TRAVEL
5 . . . AND OFTEN MUCH MORE MAPS TIME OF DAY CROSS TRACK ERROR ESTIMATED TIME OF ARRIVALESTIMATED TIME ENROUTECOORDINATES OF CITIES & TOWNSAREA MEASUREMENTETC.
6 SOME GPS APPLICATIONS HIKING HUNTING MILITARY NATURE STUDY MARITIME COMMERCE & GOVERNMENTRECREATIONALHIKINGHUNTINGNATURE STUDYFISHINGBOATINGBIKINGSKIINGSNOWMOBILINGGEOCACHINGGOLF !MILITARYMARITIMEAUTOMOTIVESURVEYINGAVIATIONAGRICULTUREFORESTRYENVIRONMENTALPUBLIC SAFETY
7 HOW CAN WE UTILIZE GPS IN 4-H PROGRAMMING? EDUCATIONAL & OPERATIONAL USESWILDLIFE MAPPINGHIGH ADVENTURELEADER TRAININGSEARCH & RESCUEBIG TREE SEARCHSCIENCE & TECHNOLOGYHUNTER EDUCATIONTRIP PLANNING & SAFETYENVIRONMENTAL EDUCATIONFISHING & CANOEINGAND LOTS MORE !
8 The NAVSTAR System24 Satellites orbital plates ,000 miles up 12 hour orbitfrom GPS Land Navigation by Michael Ferguson
9 THE EARTH: Latitude & Longitude from GPS Land Navigation by Michael Ferguson
10 ERROR SOURCES Multipath interference Atmospheric/Ionospheric Geometric DOP Clock Ephemeris S.A. (now turned off) and Human Error!LINE OF SIGHTfrom GPS Land Navigation by Michael Ferguson
11 Plot of position accuracy using standard Lowrance GPS receiver (stationary). Note the differences in scale5.5 hour period immediately prior to shutoff of selective availability8 hour period immediately after shutoff of selective availability
12 MAP DATUMSWGS84 World Geodetic System Default datum on Garmin and most other GPS receivers. Most accurate datum, but not yet in wide use on maps.NAD27 (NAD27CONUS) North American Older datum used on most USGS topographic maps. (We will be using this datum for the workshop)NAD83 North American Datum Very similar to WGS84. Used on newer USGS maps.and hundreds of others!
13 COORDINATE SYSTEMSLATITUDE / LONGITUDE (ANGULAR) DEGREES - MINUTES - SECONDSUTM / UPS (RECTANGULAR, METRIC) UNIVERSAL TRANSVERSE MERCATOR (WE WILL BE USING UTM IN OUR FIELD EXERCISES) UNIVERSAL POLAR STEREOGRAPHICMGRS (UTM USING ALPHANUMERIC I.D.) MILITARY GRID REFERENCE SYSTEMOTHERS …TOWNSHIP & RANGE, STATE PLANE COORDINATE, ETC.
14 STANDARD CIVILIAN RECEIVERS (Selective Availability OFF) ACCURACYSTANDARD CIVILIAN RECEIVERS (Selective Availability OFF)HORIZONTAL ACCURACY TO 15 METERS (49.2’) OR BETTERVERTICAL ACCURACY (altitude) TO 100 METERS (328’)
15 SYSTEMS TO IMPROVE POSITION ACCURACY DIFFERENTIAL GPS (DGPS)SYSTEMS TO IMPROVE POSITION ACCURACYCoast GuardCommercial Ground & Satellite Based CorrectionWide Area Augmentation System (WAAS)
16 WIDE AREA AUGMENTATION SYSTEM FAA SPONSORED GEO-STATIONARY SATELLITES (# 35 for us) FREE ACCESS ACCURACY TO 3 METERS INSTALLED ON MOST NEW (2001+) GPS MODELS
32 ENTERING COORDINATES TO CREATE A NEW WAYPOINT IN ETREX + ON MENU PAGE, SELECT MARK.NAME IT & SELECT SYMBOL (optional)ENTER ELEVATION (optional)ENTER COORDINATE DATASELECT “OK” AND YOU’RE DONE
33 PROJECTING COORDINATES TO CREATE A NEW WAYPOINT IN ETREX+ CREATE A NEW WAYPOINT BY ENTERING A BEARING AND DISTANCE FROM YOUR CURRENT POSITION OR ANY EXISTING WAYPOINTON MENU PAGE SELECT FIND.SELECT AN EXISTING WAYPOINT AND ENTERFROM MENU OPTION, SELECT PROJECT.NAME IT & SELECT SYMBOL (optional)ENTER DISTANCEENTER BEARINGSELECT OK AND YOU’RE DONE
34 ETREX+ AREA MEASUREMENT: Venture Legend Vista Legend & Vista onlyAll 3 modelsAll 3 models
35 AREA MEASUREMENT TECHNIQUES Using Venture/Legend/Vista GPS Receiver alone: *Calculate from perimeter measurement *Accessories - “area calculation” function *Route - “route area’ function (not Venture).Using Terrain Navigator (TN) alone: *Distance Tools - trace & calculate. *Track Tool - trace, finish, calculate. *Route Tool - trace, edit/loop, calculate.Using combination of GPS and Terrain Navigator: *Transfer GPS track to TN for calculation. *Transfer GPS route to TN for calculation. *Transfer GPS corner waypoints to TN. *Transfer TN waypts, track, or route to GPS.
36 AREA MEASUREMENT USING “ACCESSORIES” 1. On Menu page, enter Accessories2. Enter Area Calc. (area calculation triangle).3. Highlight and press Start (stop will appear).4. Travel perimeter of the tract, then press Stop.5. Record and save (as a track) if desired.6. Clear the track log.Area and perimeter measurements can be displayed in in a variety of units.
37 AREA MEASUREMENT USING “ROUTE” (Legend & Vista only) 1. On Main Menu page, enter Route.2. Enter New (unless using an existing route).3. Enter a sequence of waypoints (first and last should be the same).4. Name and save the route.5. Highlight route and select Route Area on the options menu.Area measurement can be displayed in a variety of units.Perimeter and leg distances can be viewed as selectable fields
38 SETTING UP GPS CRUISE LINES & PLOTS OR OTHER LINEAR SAMPLING IN THE FIELD WITH GPS RECEIVER: Mark starting waypoint Project (enter bearing & distance) additional plot points Create route (cruise line & plots) (This is one of several possible methods)USING TERRAIN NAVIGATOR: Mark starting waypoint; determine bearing & distances Use Route tool to draw cruise lines and plots Transfer to GPS receiver (This also is one of several possible methods)