Transcript What is GPS
Integrating GIS and
GPS
July 17, 2015
17 July 2015
Egerton University, Department of Animal
Sciences GIS Training
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Global Positioning Systems
GPS is a revolutionary
navigation system
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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
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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
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Handheld receivers are now much more accurate
Egerton University, Department of
Animal Sciences GIS Training
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How does GPS work?
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Egerton University, Department of
Animal Sciences GIS Training
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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.
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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
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More about GPS receivers
Receivers require clear line-of-sight; thus, they will not work
indoors or where tall objects obscure the sky
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Egerton University, Department of
Animal Sciences GIS Training
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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
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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
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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
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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
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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
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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
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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
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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
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Egerton University, Department of Animal
Sciences GIS Training
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For more information…
Books from ESRI Press
Integrating GIS and the Global Positioning
System
Fun with GPS
Donald Cooke
Community Geography: GIS in Action
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Karen Steede-Terry
Kim Zanelli English and Laura S. Feaster
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Animal Sciences GIS Training
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For more information…
Garmin website
Trimble GPS
http://www.garmin.com/
www.trimble.com/gps
How stuff works
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www.howstuffworks.com
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Animal Sciences GIS Training
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