Raymarine GPM400 Reference Manual page 67

Course Up (C-UP)
In Course Up mode, the chart is static and oriented with your cur-
rent course upwards. When you change heading, the ship symbol
moves accordingly. If you select a new course, the chart will reset
to display the new course upwards.
The reference used for Course Up depends upon the data available
at a given time. The system prioritizes data in the following order:
1. Bearing from origin to destination, i.e. intended course.
2. Locked heading from an autopilot.
3. Bearing to waypoint.
4. Instantaneous heading.
If heading data becomes unavailable while in this mode, a warning
message is shown and the chart shows 0° heading in relative
motion mode.
To set the chart orientation
1. Press the PRESENTATION softkey.
2. Select CHART MODE AND ORIENTATION.
3. Toggle to your preferred option on the ORIENTATION softkey.
Motion mode
The motion mode controls how your vessel's progress relative to
the chart is represented on screen. There are three options on the
motion mode softkey:
• Relative motion (RM)
• True motion (TM)
• Autorange (AR)
When you pan the chart or use Find Cursor, the motion mode is
suspended. This is indicated in the status bar by putting the motion
name in parentheses. Manually changing the range in autorange
also suspends motion mode.
When a chart window is set to SYSTEM view the motion mode will
be set but not synchronized across other system view windows.
Relative motion
The default motion mode is relative motion. In this mode, the chart
is redrawn relative to your position as you make progress, so that
your vessel is always shown in the same place on the screen. The
position in which your boat is shown on-screen can be altered with
the vessel offset option.
True motion (TM)
When the motion mode is set to true motion, the chart view
remains static and your vessel is shown moving across it as you
make progress. As your position approaches the edge of the
screen, the chart display is redrawn to include the area ahead of
you.
You cannot select True Motion when the orientation is set to Head
Up.
Autorange
Autorange selects and maintains the largest possible scale of chart
that will display both your vessel and your target waypoint. Autor-
ange is not available if radar-chart synchronization is on.
Relative motion with optional vessel offset
In relative motion mode you can specify whether the boat is fixed in
the centre of the window (0 offset, default) or offset by 1/3 or 2/3.
The latter options give you a greater view ahead of your position.
67
Chapter 5: The Chart Application