Lowrance electronic Lowrance GlobalMap 5200C - Manual (Page 88)

82
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 (al-
ways 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: From the Map Page, press
MENU
| ↓ to
M
AP
D
ATA
|
ENT
. Press ↓ to
D
RAW
M
AP
B
OUNDARIES
| → to
R
ANGE
R
INGS
. With the op-
tion 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.
To set Lat/Long Grid: From the Map Page, press
MENU
| ↓ to
M
AP
D
ATA
|
ENT
. Press ↓ to
P
OPUP
M
AP
I
NFORMATION
| → to
L
AT
/L
ON
G
RID
L
INES
. 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 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 cre-
ated using different datums will show the same latitude/longitude in
slightly different locations.
All datums are named. The GPS system is based on the WGS-84 da-
tum, 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 different datums. Different datums can be selected; to
change the datum:
1. Press
MENU
|
MENU
| ↓ to
GPS S
ETUP
|
ENT
| ↓ to
D
ATUM
S
ELECTION
|
ENT
.
2. Scroll ↓ or ↑ to select the desired datum, then press
ENT
.
3. To return to the last page displayed, press
EXIT
|
EXIT
. A list of the
datums used by this unit is in the back of this manual.