75
After the option is set, press
EXIT
to return to the page display.
Draw Boundaries
Press
MENU
|
↓
to
M
AP
D
ATA
|
ENT
. Press
↓
to
D
RAW
B
OUNDARIES
. With the op-
tion highlighted, press
ENT
to check it (turn on) and uncheck it (turn off.)
After the option is set, press
EXIT
to return to the page display.
Fill Land With Gray
Press
MENU
|
↓
to
M
AP
D
ATA
|
ENT
. Press
↓
to
F
ILL
L
AND
W
ITH
G
RAY
. With the
option highlighted, press
ENT
to check it (turn on) and uncheck it (turn off.)
After the option is set, press
EXIT
to return to the page display.
Map Overlays (Range Rings; Lat/Long Grid)
The map screen can be customized with four range rings and/or grids that
divide the plotter into equal segments of latitude and longitude.
Range rings are handy for visually estimating distances on the map. The
ring diameters are based on the current zoom range. For example: at the
100 mile zoom, the screen will show two rings with your current position in
the center. The large ring touching the left and right sides of the screen is
100 miles in diameter (same as the zoom range). The second smaller ring
is 50 miles in diameter (always 1/2 the zoom range).
The distance from your current position to the smaller ring (the ring's ra-
dius) is 25 miles (always 1/4 the zoom range). With the arrow keys and
map cursor, you can scroll the map to see the third and fourth rings. In this
example, the distance to the third ring is 75 miles and distance to the
fourth ring is 100 miles from your current position.
To set range rings:
Press
MENU
|
↓
to
M
AP
D
ATA
|
ENT
. Press
↓
to
R
ANGE
R
INGS
. With the option highlighted, press
ENT
to check it (turn on) and un-
check it (turn off.) After the option is set, press
EXIT
to return to the page
display.
To set Lat/Lon Grid:
Press
MENU
|
↓
to
M
AP
D
ATA
|
ENT
. Press
↓
to
L
AT
/L
ON
G
RID
. With the option highlighted, press
ENT
to check it (turn on) and un-
check it (turn off.) After the option is set, press
EXIT
to return to the page
display.
Map Datum Selection
Maps and charts are based on a survey of the area that's covered by the
map or chart. These surveys are called "Datums." Maps that are created
using different datums will show the same latitude/longitude in slightly dif-
ferent locations.
All datums are named. The GPS system is based on the WGS-84 datum,
which covers the entire world. Other datums may also cover the entire
world, or just a small portion of it. By default, your position shows using the
WGS-84 datum. However, it can show your position using one of 191 dif-
