Lowrance electronic GlobalMap 100 - Manual (Page 57)

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Map Fix
Map Fix is used with charts or maps. This system asks
for a reference position in latitude/longitude, which you
take from a marked location on the map. It then shows
the present position as distance on the map from that
reference point. For example, if it shows a distance of
UP 4.00” and LEFT 0.50”, you then measure up four
inches and to the left a half-inch from the reference
point on the map to find your location.
To use this format, you need to follow these steps in
order. First, take your map of the area and determine a
reference latitude/longitude. (Note: in order for this
system to work, the latitude/longitude lines must be
parallel with the edge of the map. USGS maps are
parallel, others may not be. Also, this works better with
smaller scale maps.) The reference position can be
anywhere on the map, but the closer it is to your
location, the smaller the numbers will be that you’ll have
to deal with.
Once you’ve decided on a reference position, you’ll
need to save it as a waypoint. See the waypoint section
for information on saving a waypoint using the EDIT
Position method. Save the reference position as a
waypoint. Exit from the waypoint screens.
Press the MENU key, then select GPS Setup. Now
select “Map Fix Setup” . ”Reference Point” is highlighted.
Press the right arrow key. Select the waypoint number
that you saved the reference point under. Select “SET
REFERENCE” and press the right arrow key. The unit
returns to the Map Fix Setup menu. Now select “Map
Scale”. Enter the map’s scale. This is generally at the
bottom of the paper map. It’s shown as a ratio, for
example 1:24000. In this example, we entered 24000
as a map scale. (Ignore the 1:) The unit returns to the
Map Fix Setup screen.
Finally, press the EXIT key to erase this menu. Now
select “Position Format”. Select Map Fix from the list
and press the EXIT key. All position information now
shows as a distance from the reference point you
entered and saved as a waypoint earlier.