Obstructions - Lowrance 100 Installation And Operation Instructions Manual

Obstructions

Your Airmap has obstruction capability. The database
installed in your unit lets you see ground obstructions
on the map display such as radio and television tow-
ers. The obstruction portion of the database covers all
of the continental United States, Alaska, and parts of
Canada, Mexico, and Bahamas.
On the screen shown at right, three obstructions are
shown. Three different symbols are used to show them,
depending on their height. They are:
The elevation shows beneath the symbol. If a line is beneath the eleva-
tion, then the height is AGL, or above ground level. If no line shows be-
neath the height, then it is MSL or above mean sea level.
For example, this obstruction is
315 feet AGL:
This obstructions is 315 feet MSL:
Typically, you'll need to zoom in to a range of 40 miles or less to see the
large obstruction symbols, and smaller ranges to see the larger
obstruction's height and smaller obstructions. To view smaller obstruction's
height, you may need to zoom in to the 5 mile range.
Obstructions are off by default. To turn them on, press the MENU key,
while a map is showing, then select the "MAP-1 SETUP" label and press
the right arrow key. Now select "AIR MAP OPTIONS" and press the right
SMALL - 205 to 499 feet
MEDIUM - 500 to 999 feet
LARGE - 1000 feet and above
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