Map datum selection – Lowrance electronic LCX-17M User Manual
Page 159
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Map Boundaries
From the Map Page, press
MENU
|
↓ to
M
AP
D
ATA
|
ENT
. Press
↓ to
D
RAW
M
AP
B
OUNDARIES
. With the option highlighted, press
ENT
to check it (turn
on) or uncheck it (turn off.) After the option is set, press
EXIT|EXIT
to
return to the page display.
Fill Water With White
From the Map Page, press
MENU|
↓
to
M
AP
D
ATA
|
ENT.
Press
↓ to
F
ILL
W
ATER
W
ITH
W
HITE
. With the option highlighted, press
ENT
to check it
(turn on) and uncheck it (turn off.) After the option is set, press
EXIT|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
radius) is 25 miles. 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: From the Map Page, press
MENU|
↓
to
M
AP
D
ATA
|
ENT.
Press
↓ and →
to
R
ANGE
R
INGS
. With the option highlighted,
press
ENT
to check it (turn on) or uncheck it (turn off.) After the option
is set, press
EXIT|EXIT
to return to the page display.
To set Lat/Long Grid: From the Map Page, press
MENU|
↓
to
M
AP
D
ATA
|
ENT.
Press
↓
and
→
to
L
AT
/L
ON
G
RID
L
INES
. With the option
highlighted, press
ENT
to check it (turn on) or uncheck it (turn off.)
After the option is set, press
EXIT|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 different locations.