Garmin GPSMAP 76CS Owner's Manual

Also see for GPSMAP 76CS: Quick guide Specification sheet Owner's manual

Contents

Garmin GPSMAP 76CS Owner's Manual Manual pdf 102 page image

92GPSmap 76CSMap Datums are based on amathematical model of the Earth.PositionFormatsMap DatumsWhat 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 aspecific map datum. Every chart has a map datum reference and theGPSmap 76CS 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 Position Format, and which should I use?Your current location can be viewed on the GPS in the form ofcoordinates. Since different maps and charts use different locationformats, Garmin GPS units allow you to choose the correct coordinatesystem for the type of map you are using. The most common format islatitude and longitude, which is utilized by all Garmin units. On mostmodels, you may choose to change the position format to use with othercoordinate systems. 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.AppendixMap Datums and Position Formats