Eagle 640c ユーザーガイド

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Pop-up Map Information

From the Map Data menu, highlight 

 and press

 to turn it on (check) or turn it off (uncheck). After the option is set,

press 

.

Draw Map Boundaries

From the Map Data menu, highlight 

 and press 

to turn it on (check) or turn it off (uncheck). After the option is set,
press 

.

Fill Water With White

From the Map Data menu, highlight 

 and press

 to turn it on (check) or turn it off (uncheck). After the option is set,

press 

.

Map Overlays (Range Rings; Lat/Long Grid)

The map screen can be customized with four range rings and/or grids
that divide the map 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. At a 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 (always 1/4 the zoom range). With the map cursor,
you can scroll over 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 Data menu, highlight 

and press 

 to turn them on (check) or turn them off (uncheck). After

the option is set, press 

.

To set Lat/Long Grid: From the Map Data menu, highlight 

 and press 

 to turn them on (check) or turn them off (un-

check). After the option is set, press 

 repeatedly to get back to the

main page display.

Map Datum Selection

Maps and charts are based on a survey of an area covered by a map or
chart. These surveys are called Datums. Maps created using different
datums will show the same latitude/longitude in slightly different loca-
tions.