Garmin 3200 Application Manual

Also see for iQue 3200: Operating instructions Specifications

Contents

Garmin 3200 Application Manual Manual pdf 63 page image

51AppendixMap Datums and LocationFormatsLocation Formats Map DatumsMap Datums are based on a mathematical model of the Earth.What are Map Datums and which should I use?A datum is a mathematical model of the Earth which approximatesthe shape of the Earth, and enables calculations to be carried out in aconsistent and accurate manner. The datum is physically represented bya framework of ground monuments (i.e. trig. stations) whose positionshave been accurately measured and calculated on this reference surface.Lines of latitude and longitude on a map or chart are referenced to a spe-cific map datum. Every chart has a map datum reference and the iQuehandheld 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, the map datum in the GPS unit should beset to the same datum as the map or chart to insure the most accuratenavigation.What is a Location Format and which should I use?Your current location can be viewed on the GPS in the form of coor-dinates. Since different maps and charts use different location formats,Garmin GPS units allow you to choose the correct coordinate systemfor the type of map you are using. The most common format is latitudeand longitude, which is utilized by all Garmin units. You may choose tochange the location format to use with other coordinate systems in Loca-tion Preferences. UTM/UPS (Universal Transverse Mercator/UniversalPolar Stereographic) are easy-to-use metric grids that are found on mostUSGS topographic quadrangle maps. Several other grids, including auser-definable grid (for the advanced user), may also be selected.