Garmin eTrex Manuale Utente
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 decli-
nation changes as you move around the earth. Magnetic
North is the direction in which a compass needle points.
The eTrex bearings will correspond to the compass if the
eTrex is set to magnetic north. Due to errors introduced
when map makers fl atten 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.
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 decli-
nation changes as you move around the earth. Magnetic
North is the direction in which a compass needle points.
The eTrex bearings will correspond to the compass if the
eTrex is set to magnetic north. Due to errors introduced
when map makers fl atten 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’ fi eld. Press ENTER. The ‘SETUP’ Page
appears.
the ‘SETUP’ fi eld. 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’ fi eld. 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.
page of your choice.
When you select the ‘DEFAULTS’ fi eld and press
ENTER, the ‘UNITS’ page returns to the factory settings.
You can use GARMIN’S
‘MapSource®’ Map Data
CD-ROMs to download
waypoints, tracks, and
routes.
‘MapSource®’ Map Data
CD-ROMs to download
waypoints, tracks, and
routes.
‘MAGNETIC’ north is
the default north
reference setting.
the default north
reference setting.
Reference
Units of
Measure
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