Presentation on theme: "PRACTICAL GPS APPLICATIONS IN FORESTRY & AGRICULTURE MIKE CLIFFORD VIRGINIA COOPERATIVE EXTENSION."— Presentation transcript:
PRACTICAL GPS APPLICATIONS IN FORESTRY & AGRICULTURE MIKE CLIFFORD VIRGINIA COOPERATIVE EXTENSION
Introductions; Workshop & Field Testing Objectives Basics 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 to 1. Traditional methods 2. Terrain Navigator's area calculation figures 3. Post-collection DGPS figures. Discuss available sources and resources. Evaluation and follow-up. PRACTICAL GPS APPLICATIONS IN FORESTRY & AGRICULTURE Workshop & Field Tests
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: ). GPS and GIS DEFINITIONS
BASIC INFORMATION PROVIDED BY GPS RECEIVERS... YOUR CURRENT POSITION COORDINATES (LATITUDE & LONGITUDE, UTM, MGRS, ETC.) ELEVATION (APPROXIMATE) DIRECTION TO SPECIFIED WAYPOINTS (MARKERS) (0R BETWEEN WAYPOINTS) DISTANCE TO SPECIFIED WAYPOINTS (0R BETWEEN WAYPOINTS) YOUR SPEED OF TRAVEL YOUR DIRECTION OF TRAVEL
... AND OFTEN MUCH MORE MAPS TIME OF DAY CROSS TRACK ERROR ESTIMATED TIME OF ARRIVAL ESTIMATED TIME ENROUTE COORDINATES OF CITIES & TOWNS AREA MEASUREMENT ETC.
SOME GPS APPLICATIONS MILITARY MARITIME AUTOMOTIVE SURVEYING AVIATION AGRICULTURE FORESTRY ENVIRONMENTAL PUBLIC SAFETY HIKING HUNTING NATURE STUDY FISHING BOATING BIKING SKIING SNOWMOBILING GEOCACHING GOLF ! COMMERCE & GOVERNMENT RECREATIONAL
HOW CAN WE UTILIZE GPS IN 4-H PROGRAMMING? EDUCATIONAL & OPERATIONAL USES HUNTER EDUCATION WILDLIFE MAPPING HIGH ADVENTURE TRIP PLANNING & SAFETY SEARCH & RESCUE LEADER TRAINING FISHING & CANOEINGENVIRONMENTAL EDUCATION BIG TREE SEARCH SCIENCE & TECHNOLOGY AND LOTS MORE !
from GPS Land Navigation by Michael Ferguson The NAVSTAR System 24 Satellites 6 orbital plates 11,000 miles up 12 hour orbit
from GPS Land Navigation by Michael Ferguson THE EARTH: Latitude & Longitude
from GPS Land Navigation by Michael Ferguson LINE OF SIGHT ERROR SOURCES Multipath interference Atmospheric/Ionospheric Geometric DOP Clock Ephemeris S.A. (now turned off) and Human Error!
Plot of position accuracy using standard Lowrance GPS receiver (stationary). Note the differences in scale 5.5 hour period immediately prior to shutoff of selective availability 8 hour period immediately after shutoff of selective availability
MAP DATUMS WGS84 World Geodetic System 1984 Default datum on Garmin and most other GPS receivers. Most accurate datum, but not yet in wide use on maps. NAD27 (NAD27CONUS) North American 1927 Older datum used on most USGS topographic maps. (We will be using this datum for the workshop) NAD83 North American Datum 1983 Very similar to WGS84. Used on newer USGS maps. –and hundreds of others!
COORDINATE SYSTEMS LATITUDE / LONGITUDE (ANGULAR) DEGREES - MINUTES - SECONDS UTM / UPS (RECTANGULAR, METRIC) UNIVERSAL TRANSVERSE MERCATOR (WE WILL BE USING UTM IN OUR FIELD EXERCISES) UNIVERSAL POLAR STEREOGRAPHIC MGRS (UTM USING ALPHANUMERIC I.D.) MILITARY GRID REFERENCE SYSTEM OTHERS … TOWNSHIP & RANGE, STATE PLANE COORDINATE, ETC.
ACCURACY STANDARD CIVILIAN RECEIVERS (Selective Availability OFF) HORIZONTAL ACCURACY TO 15 METERS (49.2) OR BETTER VERTICAL ACCURACY (altitude) TO 100 METERS (328)
DIFFERENTIAL GPS (DGPS) Coast Guard Commercial Ground & Satellite Based Correction Wide Area Augmentation System (WAAS) SYSTEMS TO IMPROVE POSITION ACCURACY
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
NAVIGATION BASICS 1. KNOW YOUR POSITION 2. PLAN YOUR ROUTE 3. STAY ON YOUR ROUTE 4. RECOGNIZE YOUR DESTINATION
Garmin eTrex Models with Area Measurement Capability eTrex+ Venture $ Legend $ Vista $285.00
ENTERING COORDINATES TO CREATE A NEW WAYPOINT IN ETREX + ON MENU PAGE, SELECT MARK. NAME IT & SELECT SYMBOL (optional) ENTER ELEVATION (optional) ENTER COORDINATE DATA SELECT OK AND YOURE DONE
PROJECTING COORDINATES TO CREATE A NEW WAYPOINT IN ETREX+ ON MENU PAGE SELECT FIND. SELECT AN EXISTING WAYPOINT AND ENTER FROM MENU OPTION, SELECT PROJECT. NAME IT & SELECT SYMBOL (optional) ENTER DISTANCE ENTER BEARING SELECT OK AND YOURE DONE CREATE A NEW WAYPOINT BY ENTERING A BEARING AND DISTANCE FROM YOUR CURRENT POSITION OR ANY EXISTING WAYPOINT
All 3 models Legend & Vista only ETREX+ AREA MEASUREMENT: Venture Legend Vista
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.
AREA MEASUREMENT USING ACCESSORIES 1. On Menu page, enter Accessories 2. 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.
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
SETTING UP GPS CRUISE LINES & PLOTS OR OTHER LINEAR SAMPLING IN THE FIELD WITH GPS RECEIVER: 1. Mark starting waypoint 2. Project (enter bearing & distance) additional plot points. 3. Create route (cruise line & plots). (This is one of several possible methods) USING TERRAIN NAVIGATOR: 1. Mark starting waypoint; determine bearing & distances. 2. Use Route tool to draw cruise lines and plots. 3. Transfer to GPS receiver. (This also is one of several possible methods)
AERIAL PHOTOTOPOGRAPHIC MAP
TOPO MAP MARGIN INFO: BOTTOM CENTER
TOPO MAP MARGIN INFO: BOTTOM LEFT
TOPO MAP MARGIN INFO: BOTTOM RIGHT
DEMONSTRATIONS: MapTech TERRAIN NAVIGATOR and Garmin MAPSOURCE