Garmin etrex legend cx Benutzerhandbuch

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PPENDIX

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ATUMS

 

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OCATION

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ORMATS

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 the eTrex can be set 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.

Your current location is 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 for other 

coordinate systems. UTM/UPS (Universal Transverse 

Mercator/Universal Polar Stereographic) projection 

formats 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).