NAVMAN
8120/8084
Installation and Operation Manual
75
Palette
Select the color scheme for the LCD window.
The options are:
Normal
Sunlight
: Brighter colors, more visible in
sunlight.
Night
: Reversed colors for night, to
preserve night vision.
Map datum
Instrument GPS positions are based on a
worldwide reference (datum) known as WGS
84. Most paper charts are based on WGS
84. However, some paper charts are based
on other datums In these cases, the latitude
and longitude coordinates of objects on the
Instrument chart window are different to
the latitude and longitude coordinates of
these objects on the paper chart. This applies
to all objects, such as the boat, waypoints,
tracks, lines of latitude and longitude and
cartographic features such as land, rocks,
buoys and depth contours.
Use
Map datum
to select the Instrument
map datum to match the datum of the paper
chart. Then, the latitude and longitude
coordinates of objects displayed on the
Instrument will change to match the
corresponding coordinates on the paper
chart.
Setting map datum
1 In the Chart setup menu, select Map
datum.
2 Select the map datum for the paper chart
you are using.
3 If you select a datum other than WGS 84
the Instrument asks if you want to apply
the NMEA datum offset (see below).
!
WARNING
Map shift is for eliminating minor offsets.
It should not be used if the correct datum
is available. Use map shift with caution:
incorrect application will cause incorrect
boat positions.
!
WARNING
When you change to a chart with a
different datum, change the Instrument
map datum again.
NMEA datum offset
If you select a map datum other than WGS
84, the map datum offset can be applied to
latitude and longitude coordinates sent on
the Instrument NMEA output:
Latitude and longitude coordinates
displayed on any NMEA repeater do not
match the coordinates on the Instrument.
Latitude and longitude coordinates
broadcast on any NMEA VHF transmitter
will be the same as the coordinates on a
WGS 84 chart.
Latitude and longitude coordinates
displayed on any NMEA repeaters match
the coordinates on the Instrument.
However, latitude and longitude
coordinates broadcast on any NMEA VHF
transmitter will be slightly offset from
coordinates on a WGS 84 chart.
Map shift
Some charts have consistent position errors.
To correct this, apply a map shift. After a map
shift:
The positions of cartographic features
(such as land, rocks, buoys and depth
contours) move on the Instrument chart
window to where they should be.
The positions of the boat, waypoints,
tracks, and lines of latitude and longitude
on the Instrument chart window remain
unchanged.
