Cheap GPS (From xkcd.com)

Global Positioning System And Tree Identification

 Global Positioning System and Tree Identification  Presented at the MAEOE Conference, 02/06/10 by: Lathrop E. Smith Environmental Education Center Montgomery County Public Schools

Introduction: Who am I? Rationale: STEM and NCLI Outline: Lots of Directions, Outside, Back Inside to Wrap Up

Introduction: Who am I? Mark Granger – L. E. Smith Center MCPS

Rationale: STEM Science Technology Engineering and Math New emphasis in MSDE and at the Federal Level

Rationale: NCLI – No Child Left Inside Maryland Partnership for Children in Nature Also Federal support

Lots of Directions, Outside, Back Inside to Wrap Up

A Little Tree Vocabulary...

Coniferous or Deciduous?

A Little Tree Vocabulary... Alternate or Opposite?

A Little Tree Vocabulary... Simple or Compound?

A Little Tree Vocabulary... Lobed? Serrated? Margins?

 What is GPS and how does it work? GPS - Global Positioning System

GPS – Global Positioning System  Developed for use by the U.S. military at the end of the cold war to track ICBM missiles.  Fully operational 1995 (selective availability turned off May 1, 2000) Original Manpack developed for use by military

GPS – Global Positioning System  24 satellites orbit 22,200 km from earth, with five to eight satellites always visible from any point on earth  GPS receiver needs to make contact with signals from three satellites in order to compute a location on earth  Contact with a fourth satellite allows for the computation of time.

GPS – Global Positioning System

 Cost of GPS receivers from $100 for hand-held unit (accurate within 10 meters horizontally) to over $50,000 for research receivers (accurate within 1 cm horizontally)  Used extensively for marine and air navigation and mapping. Growing popularity of GPS use by hikers, hunters, fisherman, and gamers.  Scientific uses include atmospheric studies, plate tectonics, including mapping of volcanoes, and collection of coastline data  No cost to use the system

GPS – Global Positioning System  1.GPS technology relies on the use of satellites.  2.To locate a satellite, a GPS receiver measures distance using the travel time of radio signals  3.To measure travel time, GPS needs very accurate timing which it achieves with some tricks. Along with distance, you need to know exactly where the satellites are in space. False code signals are created, one which the satellite signals, and one that the GPS matches. When the two signals “line up”, the time is determined. The GPS emits a radio frequency, similar to the MHz on your radio, which increases the accuracy of the GPS. Finally you must correct for any delays the signal experiences as it travels through the atmosphere.

GPS – Global Positioning System

How Do You Use a GPS?  Each brand of GPS is set up differently.  At the Smith Center, we use Garmin etrex units.

GPS – Global Positioning System Internal GPS Antenna UP Button DOWN Button PAGE Button POWER Button LCD Display with Backlight ENTER Button

GPS – Global Positioning System The GPS receiver displays pages with separate functions.  There are four main pages that you will be using to navigate:

GPS – Global Positioning System Let’s Get Started!  All GPS receivers operate on information gathered from satellites. In order to receive the satellite signals, you must be outside, away from any objects such as trees or overhangs that might block the signal. You need a clear view of the sky.

GPS – Global Positioning System Step 1: Push and hold down the POWER BUTTON to turn the unit on. You’ll see the “Welcome” page for a few seconds, followed by the Satellite Page.

GPS – Global Positioning System How do I know I’m ready to go?  When you see the “Ready to Navigate” message, you know the etrex has locked onto the satellites’ signals.  This must be displayed before you can begin using the GPS to navigate.  Signal strength bar will be filled in to indicate the GPS has locked onto a signal.

GPS – Global Positioning System Satellite Page Basics:  Two display pages: Normal Skyview that shows the satellites, satellite signal strength, and estimated accuracy. Advanced Skyview that shows you the numbered satellites being used, their signal strength, and their position in relation to you.

GPS – Global Positioning System What does the MAP page do?  The map page shows where you are and uses an animated figure to show where you are actually going.  Waypoint names and symbols are also shown.

GPS – Global Positioning System Map Page Basics:  You can change the map scale by pressing and holding the UP button to view a larger area, or the DOWN button to view a smaller area.  You can change the scale from 200 ft to 800 miles to view your entire trip!

GPS – Global Positioning System NAVIGATION PAGE BASICS  The Navigation Page guides you to your destination. It shows you your moving direction and speed. If you have a specific destination entered into the GPS, the page shows you the name of the location, the distance, and it displays a direction arrow that is shown in the compass ring.

GPS – Global Positioning System NAVIGATION PAGE BASICS: We’ll be using LATITUDE and LONGITUDE coordinates to describe locations. Latitude measures distances North or South from the Equator (0°) towards the Poles. (90°)

GPS – Global Positioning System NAVIGATION PAGE BASICS: We’ll be using LATITUDE and LONGITUDE coordinates to describe locations. Longitude measures distances West or East from the Prime Meridian (0° at Greenwich, UK).

GPS – Global Positioning System Lines of Longitude

GPS – Global Positioning System Lines of Latitude

GPS – Global Positioning System Combined!

GPS – Global Positioning System The units that we will be using to measure are: Degrees (°) North 39° Minutes ( ‘ ) 06 And... THOUSAND THS of Minutes!.582’ West 77°06.086’

GPS – Global Positioning System MAIN MENU BASICS:  With the main menu you can create waypoints, routes, save and view your track logs. If you select MARK, you can mark your location as a waypoint.

GPS – Global Positioning System GOING TO A WAYPOINT:  Press the PAGE button and switch to the MENU Page  Press UP or DOWN and highlight WAYPOINTS. Press ENTER..  Press the UP or DOWN button and highlight the alphabetical tab for the waypoint. Press ENTER.  This will take you to a list of waypoints.  Highlight a waypoint, and press ENTER.

GPS – Global Positioning System  REVIEW WAYPOINT page appears. REVIEW WAYPOINT allows you to change coordinates, name, symbols, and delete waypoints.  On the REVIEW WAYPOINT page, press the UP or DOWN button and highlight GOTO, press enter.

GPS – Global Positioning System Using GPS Technology to Locate Trees

GPS – Global Positioning System  GPS technology allows us to identify locations of specific trees  Useful in monitoring health of trees over time  Latitude and longitude coordinates are given for each tree location

GPS – Global Positioning System GOING TO A WAYPOINT It would be VERY difficult to use the GPS Unit by itself to find your way to your waypoint, so you will also need to know how to use...

GPS – Global Positioning System A Map! Use the map to look for landmarks, to stay on trails, to gauge distances, and to find your way back!

GPS – Global Positioning System STEPS TO USING THE GPS:  From the SATELITE page, press the PAGE button until you come to the MENU page.  Scroll down to WAYPOINTS, press ENTER.  Scroll down to the tree waypoint entered. Press ENTER.  The REVIEW WAYPOINT screen will appear, select GOTO, the COMPASS page will appear.  Begin walking. The arrow will reorient in the direction you should be walking if you could walk a straight line to your waypoint. You WILL need to adjust your line of travel to avoid obstacles and to remain on trails.

GPS – Global Positioning System STEPS TO LOCATING THE TREE:  Follow the arrow and stay on trails to find desired coordinates. Remember that the GPS is only accurate within 10 meters. At this point you need to begin looking for the tree marker.  At this point, you will need to spread your group out and look for the tree marker.

GPS – Global Positioning System ONCE YOU’VE FOUND THE TREE:  Use the dichotomous key to identify the tree.  Check your identification using a field guide to North Eastern trees.  Enter the next tree number and coordinates that you wish to locate as a GPS waypoint.  Continue to the next tree.

GPS – Global Positioning System THINGS TO KEEP IN MIND:  Do not cross roads.  Stay on trails. No bushwhacking!  You may need to go around rocks or cross streams.  Stay together – do not leave your group  Use your map and compass in conjunction with the GPS  Respect the park. Take only your memories, leave only your footprints.

GPS – Global Positioning System  IMPORTANT POINTS:  GPS technology is limited – tree canopy and cloud cover affect signal strength  Be aware of your direction of travel. Use a map.  Watch the time! Return on time!