Transcript What is GPS
Integrating GIS and GPS July 17, 2015 17 July 2015 Egerton University, Department of Animal Sciences GIS Training 1 Global Positioning Systems GPS is a revolutionary navigation system 17 July 2015 24 satellites orbiting the earth Provide location within metres or less anywhere on the globe. Now available in many cars as an option Created and operated by the US Department of Defense Egerton University, Department of Animal Sciences GIS Training 2 More about GPS satellites Constellation of 27 satellites (24 active + 3 spare) Orbit 12,600 miles above earth (10,900 nautical miles) Satellites in 12 hour orbit First satellite launched in 1978, 24th became operational in 1994 Selective availability was removed in May, 2000 17 July 2015 Handheld receivers are now much more accurate Egerton University, Department of Animal Sciences GIS Training 3 How does GPS work? 17 July 2015 Egerton University, Department of Animal Sciences GIS Training 4 How does GPS work? Measuring distance by measuring time Satellites send coded signals indicating their position in space and the exact time the signals are being sent Receivers use the time it takes signal to travel from satellite to receiver to determine distance from satellite to receiver Information from multiple satellites is used to determine position through ‘triangulation’ 17 July 2015 Egerton University, Department of Animal Sciences GIS Training 5 More about GPS receivers A GPS receiver's job is to locate four or more satellites, figure out the distance to each, and use this information to deduce its own location. 17 July 2015 Hand-held receivers for recreational use with accuracy of 10-15 metres Vehicle mounted receivers for navigation or agricultural use with accuracy of < 1 meter Backpack or tripod mounted receivers for surveying use with accuracy of 5 – 10 centimeters Egerton University, Department of Animal Sciences GIS Training 6 More about GPS receivers Receivers require clear line-of-sight; thus, they will not work indoors or where tall objects obscure the sky 17 July 2015 Egerton University, Department of Animal Sciences GIS Training 7 What’s so cool about GPS? GPS units Can be used as a digital compass Can be used to determine ground speed Can store landmarks (locations) Can be used for dynamic routing Can be used for mapping applications 17 July 2015 Egerton University, Department of Animal Sciences GIS Training 8 Applications of GPS In-vehicle Navigation (car, boat, airplane) Asset Management Construction Geologic Research & Mining Military Navigation and Operations Mapping & Surveying Precision Agriculture Public Health Public Safety Wireless Communications 17 July 2015 Egerton University, Department of Animal Sciences GIS Training 9 GPS in the classroom 17 July 2015 Egerton University, Department of Animal Sciences GIS Training 10 Integrating GIS and GPS Collect a series of latitude and longitude points using GPS receivers add them into an existing digital map Skills in data collection/creation GPS reading observation Digital photos/Toposheets 17 July 2015 Egerton University, Department of Animal Sciences GIS Training 11 Classroom projects There are many ways you can incorporate GPS data collection into your classroom Possibilities include 17 July 2015 a virtual trail in your area mapping the locations of litter and garbage cans to determine if there is a relationship, and if more garbage cans are necessary collecting data about tree types and locations on school grounds and beyond gathering water samples from a local stream and taking GPS readings at each location orienteering/navigating (hiking, boating, biking, driving) Egerton University, Department of Animal Sciences GIS Training 12 Getting started GPS units - Garmin eTrex perfect for introducing students to field data collection and the power of GPS industry's smallest and lightest handheld GPS receiver sleek waterproof housing will fit in your shirt pocket and weighs only 5.3 ounces a 12 channel parallel receiver, differential ready, with a built-in patch antenna runs for 22 hours on just two AA batteries Pencil, clipboard, paper 17 July 2015 Egerton University, Department of Animal Sciences GIS Training 13 Getting started - additions Connection cables for your GPS units Allow you to download data from your GPS unit to your computer Free extension available to convert to shapefile Local data Create a base map for viewing the data you have collected Provides context and other features for GIS analysis with ArcView Digital camera 17 July 2015 Egerton University, Department of Animal Sciences GIS Training 14 Collecting data Collect data in the field using GPS 17 July 2015 Write down point coordinates and additional data observations - OR Use tracking function of your unit to store points, lines, or polygons, and write down additional observations Egerton University, Department of Animal Sciences GIS Training 15 Using the data you collect Manually enter the coordinates and observations into a table (Excel, etc.) Save as a .dbf file Add to ArcView Use “Add X,Y” or “Add Event Theme” to create points on your map - OR - Use your GPS unit cable to download the data from the unit to your computer 17 July 2015 Egerton University, Department of Animal Sciences GIS Training 16 For more information… Books from ESRI Press Integrating GIS and the Global Positioning System Fun with GPS Donald Cooke Community Geography: GIS in Action 17 July 2015 Karen Steede-Terry Kim Zanelli English and Laura S. Feaster Egerton University, Department of Animal Sciences GIS Training 17 For more information… Garmin website Trimble GPS http://www.garmin.com/ www.trimble.com/gps How stuff works 17 July 2015 www.howstuffworks.com Egerton University, Department of Animal Sciences GIS Training 18