Lowrance 5150c 操作ガイド

82 

Fill Water With White 
From the Map Page, press 

|

↓ to 

|

. Press 

↓ to 

. With the option highlighted, press 

 to check it 

(turn on) and uncheck it (turn off.) After the option is set, press 

|

 to return to the page display. 

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 (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: From the Map Page, press 

|

↓ to 

|

. Press 

↓ to 

. With the option highlighted, press 

 

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

press 

|

 to return to the page display. 

To set Lat/Long Grid: From the Map Page, press 

|

↓ to 

|

. Press 

↓ to 

. With the option highlighted, 

press 

 to check it (turn on) and uncheck it (turn off.) After the op-

tion is set, press 

|

 to return to the page display. 

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.