Garmin eTrex Owner's Manual - Page 38

Reference Units of Measure 'MAGNETIC' north is the default north reference setting. 36 North Reference 'Reference' refers to the orientation of a map's grid. Map makers try to align the vertical lines on a map with 'True North'. True North is the direction from any location on the earth's surface to the "north pole". Maps are typically referenced to true north. Because a compass points to magnetic north, not true north, maps indicate the difference between true and magnetic north with something called 'declination'. The amount of declination changes as you move around the earth. Magnetic North is the direction in which a compass needle points. The eTrex bearings will correspond to a compass if the eTrex is set to magnetic north. Due to errors introduced when map makers flatten the earth's sphere onto paper, not all of the grid lines drawn on the map point exactly to the north pole, so the north indicated by the grid lines is called 'Grid North'. But, the difference is usually small enough that 'Grid' north can be considered the same as True North for travelling on land. If necessary, you can correct for the difference between Grid North and True North manually. To change the North Reference: 1. Press the PAGE Button and switch to the 'MENU' Page. Use the UP and DOWN Button and highlight the 'SETUP' field. Press ENTER. The 'SETUP' Page appears. 2. Press the UP or DOWN Button to select 'UNITS'. Press ENTER. The 'UNITS' Page appears. 3. Press the UP or DOWN Button and select the 'NORTH REF' field. Press ENTER. 4. Press the UP or DOWN Button to select the desired reference. Press ENTER. Press PAGE to return to the page of your choice. When you select the 'DEFAULTS' field and press ENTER, the 'UNITS' page returns to the factory settings.