Introduction to Global
First Nations GIS Workshop
December 9-10, 2008
A brief history…
• 1970s - first global GPS established by US
• 1980s - NAVSTAR-GPS used by US DND
• 1983 - Korean Airlines flight 007 incident.
Reagan made GPS available for public
… a brief history.
• 1994 - NAVSTAR came online for public use.
– Selective Availability (SA) turned ON - differential
correction required for accurate positions.
• 2000 - Clinton directed that SA be turned OFF.
• Wide variety of receivers & features.
• Some multi-system receivers.
• 20+ channels on most receivers.
• Improvements in satellite technology.
A GNSS has satellites and…
GPS Satellite GPS Constellation
(NAVStar has ~30 satellites)
… position correction.
• Wide Area Augmentation
System (WAAS) – free.
• Other correction systems:
– European Geostationary
Service. - free
– Differential GPS (DGPS) $.
– Inertial Navigation Systems
(vehicles, missiles) $$.
Global Navigation Satellite
– Primarily for military
– NAVSTAR-GPS - US DND
• Only GNSS currently operational
– Global'naya Navigatsionnaya Sputnikovaya Sistema (GLONASS) -
• To be restored by 2010
– Civilian navigation requirements
– Planned to be available by 2012
– GALILEO positioning system – EU
– Indian Regional Navigational Satellite System (IRNSS)
– COMPASS - China
• All new receivers are WAAS enabled.
• Coordinates for position are calculated from GNSS data
(satellite position and correction).
• Provide user with coordinates, time & direction.
• User can select local coordinate system and datum.
Receiver calculates and displays.
• Data collected & stored on receiver using:
– Geographic Coordinate System (GCS).
– Latitude & Longitude in Decimal Degrees (DD).
– Datum is World Geodetic System 1984 (WGS-84).
• Data must be downloaded, put into GIS format and is
Receivers – Group 1 Garmin
• $150 - $500
• All have navigation.
• 3-5 metre accuracy in
good conditions. Garmin
• Mid-range have mapping.
Can load custom maps
from GIS (not easily).
• Some have built-in
camera and voice
• Low to medium
Receivers – Group 2
• $1500 - $3000
• Mobile GIS (ArcPad,
PathAway, etc). MobileMapper 6
• 3 m. accuracy in good
• Windows Mobile OS.
• Electronic forms, etc. Trimble
• Medium to high Juno SC
Receivers – Group 3
• $6000 - $10000
• Capable of sub-metre
accuracy in good
– High accuracy
requires a nearby GPS
base station and post-
• Windows Mobile O/S Magellan
• High complexity.
Receivers – Group 4
• $25,000 +
• Survey grade
• Very high complexity.
Evaluating GPS Receivers
• Are desktop & receiver interface user-friendly?
– Windows CE gives software options (ArcPad, PathAway, etc.)
– Ease of importing background data (MapSource or NRVIS)
– Ease of data transfer.
– Is conversion required to get data into correct format?
• Is the receiver screen easily seen under a clear sky?
• Does the receiver meet military ruggedness?
• Type of batteries and expected life under normal use.
• User acceptance of receiver and desktop software.
• Consider the life of GPS receiver technology is about 3
• Suggest buying one receiver and evaluate it for 6
months (all seasons).
Factors Affecting Data Collection
– Vegetation density
– Acceptance of technology – Precipitation in air & on
– Patience canopy
– Human body
• Structures & Vehicles
– error increases near
– Experience concrete or metal
– Understanding limits of • Terrain
GPS – Valley, base of cliff
– Understanding GIS • Atmosphere
capabilities – Rain, clouds, ionosphere
• Time of year • Receiver clock errors.
– Heavy dew on canopy in • Orbital or ephemeris
– Leafless period is best
– Dew is more of a problem
in the late summer & early • Intentional degradation of
fall the satellite signal.
for GPS and Mobile GIS Projects
• Consult (or hire) a GIS specialist!
• Mapping scale affects target accuracy
– 3 m. accuracy is adequate for 1:5000 or smaller
– 7 m. accuracy is fine for 1:10000 or smaller
– MNR has target of 10 m. accuracy for most values mapping.
• Check existing GPS collection standards & guidelines.
• Background data required for Mobile GIS.
– MapSource, Fugawi NTS, custom geotiff.
• User preferences
– Size of receiver, backpack with antenna.
– Short battery life below freezing.
• Establish documentation procedures for field and post-processing.
for GPS and Mobile GIS Projects
• Features to be mapped
– Point, line, polygon
• Improved accuracy with averaging positions.
– 30 positions per point, 3 for line.
• Establish minimum polygon size and field capture methods.
– If target accuracy is 10 m., then 20 m. is minimum width of the polygon
feature to be mapped. Smaller areas will be lines or points depending
– Use averaged points at significant locations to capture small polygons.
• Exporting GPS data to your GIS:
– Desktop interface.
– DNR GARMIN.
– GPS Babel converts GPS data formats.
Ted Hiscock, GIS Officer
Ontario Ministry of Natural Resources
31 Riverside Drive
Pembroke, ON K8A 8R6