NAV 44/7/4
3.5.3 The mariner should be aware that
discrepancies may exist between the chart and such precise
positioning systems as differential GPS. The mariner should
check for these as opportunity permits.
3.6 The mariner should be able to
enter chart corrections and his own notes manually, in a
convenient manner. A means should be provided of
distinguishing this added information from the chart database
information on the display. The ECS should provide a means of
keeping a record of the corrections applied.
[3.7 An updating service for the
chart database should be provided at regular intervals.]
4. DISPLAY OF INFORMATION
4.1 The mariner should be able to
remove vector data features from the ECS chart display, or
add features to it, in order to provide an uncluttered
display of the information needed for safe navigation under
varying conditions.
4.2 A latitude-longitude graticule
should be available to aid in correlation with the paper chart
5. SCALE
5.1 The electronic chart should
initially be displayed at the compilation scale of the
original source data.
5.2 Other scales may be used. An
indication should be given if the display scale selected is
larger than the compilation scale of the source data.
5.3 A scale-bar, screen range, or
other indication of display scale should be provided.
6. DISPLAY OF OTHER NAVIGATIONAL
INFORMATION
6.1 The chart and any additional
information should match in scale and orientation. Own-ship
sensor data should be adjustable for antenna offsets.
6.2 Other navigational information
should be distinguishable from the chart database information
on the display.
6.3 If additional information Is
shown on the display, It should be possible for the mariner
to remove clutter which may cause confusion or obliterate
information.
7. DISPLAY MODE
7.1 North up orientation should
normally be used. If other than north-up orientation is used,
the ECS should indicate the orientation of the display, and
the direction of north.
7,2 ECS should normally use true
motion in route monitoring. Other modes may be provided. If
other modes are used, the mode in use should be indicated.
7.3 The display should be refreshed
and, when necessary, the next chart brought up automatically,
so as to maintain an adequate look-ahead.
I:/NAV/44/7-4.WPD
