Map Datums And Location Formats; Gpsmap 276C Owner's Manual - Garmin GPSMAP 276C Owner's Manual

Map Datums and Location Formats

Map Datums are based on a mathematical model of the Earth.
What Are a Map Datums?
A datum is a mathematical model of the Earth that approximates
the shape of the Earth and enables calculations to be carried out in a
consistent and accurate manner. The datum is physically represented
by a framework of ground monuments whose positions have been
accurately measured and calculated on this reference surface. Lines
of latitude and longitude on a map or chart are referenced to a
specific map datum. Every chart has a map datum reference, and you
can set the GPSMAP 276C to match most of those commonly used.
If you are navigating and comparing the GPS coordinates to a map,
chart, or other reference, set the map datum in the GPS unit to the
same datum as the map to ensure the most accurate navigation.

GPSMAP 276C Owner's Manual

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PPENDIX
What is a Location Format?
Your current location can be viewed on the GPS in the form of
coordinates. Because different maps and charts use different
location formats, Garmin GPS units allow you to choose the correct
coordinate system for the type of map you are using. The most
common format is latitude and longitude, which is used by all
Garmin units.
You can choose to change the location format to use with other
coordinate systems in Location field of the Setup tab—Location
sub tab. UTM/UPS (Universal Transverse Mercator/Universal Polar
Stereographic) are easy-to-use metric grids that are found on most
USGS topographic quadrangle maps. You can also select one of
several other grids, including a user-definable grid (for the advanced
user).
For more information about using paper maps with your Garmin unit,
refer to Using a Garmin GPS with Paper Land Maps, available for
download at http://www.garmin.com/manuals/UsingaGarminGPSwit
hPaperLandMaps_Manual.pdf.
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