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33Tracker500/500i User Manual
15.0 Chart Datums
GPS derived positions are based on a worldwide reference (datum) known as WGS 1984.
Many charts are based on datums other than WGS 1984. This results in an offset between
a Lat/Lon plotted on the chart and the same Lat/Lon plotted on the Tracker500/500i. To
match the Tracker500/500i with your chart you must enter the datum specified on the chart.
See section 14.0 Setup for details on how to select a chart datum. Once your local datum
has been entered, all latitudes and longitudes, including waypoints, will match the chart.
Note: When using a number of charts with different datums it is important
to ensure that you change the datum to match the chart currently being
used. If the destination waypoint is on a different chart, be sure to
change to that chart’s datum before entering the latitude and longitude of
the destination waypoint.
Alternatively, you can manually enter a lat/lon offset value to bring the displayed lat/lon
values in line with the chart you are using. See the Setup screen for details on how to enter
a lat/lon offset.
The lat/lon offset function is typically used to match the Tracker500/500i
with older charts where an island may have a large position error, but all points around the
island have the same error.
ADINAN Adindan ADI-M Ethiopia, Sudan
AFGOOYE AFGOOYE AFG Somalia
AINELABD 70 AIN EL ABD 1970 AIN-A Bahrain Island
AMRICN SAMOA American Samoa 1962 AMA American Samoa Islands
ANNA 1 AST65 Anna 1 Astro 1965 ANO Cocos Islands
ANTIGUA Antigua AIA Leeward Islands
ARC 1950 ARC 1950 ARF-M Botswana, Lesotho, Malawi, Swaziland, Zaire,
Zambia, Zimbabwe
ARC 1960 ARC 1960 ARS-M Kenya, Tanzania
ASCN IS 1958 Ascension Island 1958 ASC Atlantic Ocean
ASTRO BCN”E” Astro Beacon E ATF Iwo Jima
ASTRODOS71/4 Astro DOS 71/4 SHB St. Helena Island
ASTR STN1952 Astronomic Station 1952 ASQ Marcus Island
AUST.GEO1966 Australian Geodetic 1966 AUA Australia and Tasmania
AUST.GEO1984 Australian Geodetic 1984 AUG Australia and Tasmania
AUST.GEO1984 Ayabelle Lighthouse PHA Djibouti
BELLEVUE Bellevue (IGN) IBE Efate & Erromango Islands (Vanuatu)
BERMUDA 1957 Bermuda 1957 BER Bermuda Islands
BOGATA Bogota Observatory BOO Colombia
CAMPO INCH Campo Inchauspe CAI Argentina
CANTON AST66 Canton Island 1966 CAO Phoenix Islands
CAPE CANAV Cape Canaveral CAC Florida, Bahamas
CAPE Cape Province CAP South Africa
CARTHAGE Carthage CGE Tunisia
CHATHAM 1971 Chatham 1971 CHI New Zealand
CHUA ASTRO Chua Astro CHU Paraguay
Tracker Datum name Datum Locality
abbreviation code
Tanslation of Locality in the datum
table is optional but please do not
translate anything else in the table.