South Carolina Geographic Alliance Global Positioning Systems for the Classroom Mark Musselman Audubon Center at Francis Beidler Forest Harleyville, South Carolina

Where is the SC Geographic Alliance?

Southeast of the Lawmakers Capitol

East of the Books Library and reflecting pool

Southeast of the Old Campus Horseshoe

Close to Campus Dining Russell House

The Callcott Building The SCGA is here!

Where is the SCGA? Would any of the previous descriptions have been sufficient for a person to find the SCGA in this building? Maybe, but is there a more precise method to describe your location on the Earth’s surface? Photo credit: NASA

Latitude and Longitude Angles measure in degrees, minutes, and seconds of an arc.

Latitude and Longitude Latitude (is "fatitude" around the waist of the Earth) measured north and south of the Equator

Latitude and Longitude Longitude measured east and west of the Prime Meridian

Latitude and Longitude Minutes (represented as ' ) and seconds (represented as '' ) of arc are different than the minutes and seconds on a clock. 1 o =60'=3600'' In fact... 1 hour of Earth's rotation covers 15 o longitude (360 o /24 hrs = 15 o )

Latitude and Longitude Key lines of latitude are: Equator (0 o ) divides the Earth into the Northern and Southern Hemispheres

Latitude and Longitude Key lines of latitude are: North Pole (actually, a point at 90 o N)

Latitude and Longitude Key lines of latitude are: South Pole (actually, a point at (-90 o or 90 o S)

Latitude and Longitude Key lines of latitude are: Tropic of Cancer (23.5 o N)

Latitude and Longitude Key lines of latitude are: Tropic of Capricorn (-23.5 o or 23.5 o S)

Latitude and Longitude Key lines of longitude are: Prime Meridian (0 o ): The Western and Eastern Hemispheres are measured west and east of the Prime Meridian to where they meet at the 180th Meridian 180th Meridian: (180 o E and 180 o W, generally the International Date Line)

Latitude and Longitude The combination of a latitude coordinate and a longitude coordinate designates a unique point on the surface of the Earth. For example… True or false: x o S/y o W is not a point within the United States.

Latitude and Longitude True Even without values for x and y (x o S/y o W ), you can answer that the statement is true because no U. S. points lie within the Southern Hemisphere.

Global Positioning System The basis of GPS is triangulation from a selection of the 24 satellites in known Earth orbit.

Global Positioning System To "triangulate," a GPS receiver (GPSr) measures distance between the receiver and the satellites using the travel time of radio signals. speed x time = distance where speed is assumed to be 300,000 km/s (speed of light)

Global Positioning System Mathematically four satellite ranges are needed to determine exact position. Three are enough if we reject ridiculous answers (points in the center of the Earth or high in the atmosphere).

Global Positioning System GPSr accuracy is diminished by:  Clock inaccuracies within satellites  Satellite location inaccuracies  Atmospheric signal interference  Signal interference caused by obstructions (trees, buildings, mountains, etc.)  Number of satellites available to the user (above the horizon) and their positions in relation to each other

Basic GPSr Operation How can I identify a GPSr?

Basic GPSr Operation Power up! Press and hold the bottom right button until the welcome page appears.

Basic GPSr Operation Getting started! Press the top button three times. The satellite page will appear. Scroll through the pages by continuing to push this button.

Basic GPSr Operation

Satellite Page

Basic GPSr Operation You are here

Basic GPSr Operation Marking your position – waypoint Press the “mark” button and your current position (coordinates) will be shown with a default 3-digit name assigned to the waypoint.

Basic GPSr Operation Marking your position – waypoint A waypoint is a “point along the way.” It may be somewhere you’ve never been or a place to which you wish to return. Press OK to save the waypoint with the assigned name – in this case, it is 001.

Basic GPSr Operation Marking your position –waypoint To change the waypoint name, toggle down until 001 is highlighted. Press the center of the thumb stick to reveal the keyboard. Toggle across the keyboard to edit.

Basic GPSr Operation Entering waypoints in advance Waypoints can be downloaded directly from a computer using free software such as EasyGPS at which accommodates most GPS models. For example, all 280 waypoints of the Foothills Trail in SC are available at hills/foothills.php

Basic GPSr Operation Entering waypoints in advance With a few clicks of the mouse, all the data for the Foothills Trail can be loaded to your GPS unit!

Basic GPSr Operation Entering waypoints in advance Pre-trip waypoints can be displayed on topographic maps, which can be loaded to a GPS unit. A desire for the easiest route is all the motivation one needs to understand contour lines.

Basic GPSr Operation Entering waypoints in advance Just as the name can be changed, so too can the location (coordinates). Toggle down until the location field is highlighted. Press the center of the thumb stick to reveal a number keypad for editing.

Basic GPSr Operation Navigating to your waypoint If you have a waypoint already displayed, simply toggle to the Goto button and press the center of the thumb stick.

Basic GPSr Operation Navigating to your waypoint If you already have waypoints loaded to your unit, press the bottom button on the left side to reveal the options. Select “Waypoints”. Waypoints may be displayed by name or by the nearest to your current position.

Basic GPSr Operation Navigation Page

Basic GPSr Operation Navigation Page After selecting to “Goto” a waypoint, the compass navigation page will appear. The compass is a graphic and not magnetic, so it likely will not be pointing toward the correct direction of travel. Once you begin to move, it will orient properly with the arrow pointing toward the destination.

Basic GPSr Operation Navigation Page An inexpensive magnetic compass and a map are essential items in the event your GPS unit fails to operate.

Basic GPSr Operation Navigation Page Turn off the unit whenever practical to conserve battery life. Remember, batteries will ALWAYS fail at the most inconvenient moment. Push and hold button until screen clears.

Geocaching

What is a Cache?

Cache - (kash) n. 1. a hiding place for treasure or provisions. 2. hidden treasure or provisions. (caching, v.) to place in a cache

Cache Name

Cache Waypoint

Cache Coordinates

Cache Rating

Cache Size

Cache Information

Cache Clues and Links Clue and key Links

Cache Page Log

Conclusion GPS technology continues to be incorporated into various aspects of our society. Understanding the concepts behind the technology as well as its use not only helps students address curriculum standards, it is an ever- increasing employment skill. A simple campus-based navigation course, geocaching, or incorporation within the curriculum are easy, effective methods for teaching students GPS skills and technology!