The Live Navigation data pages can be customized as described here. When you do a "Change Data", the items available are listed below:
Note that the displayed units can be changed in the Settings, Units menu.
Course over Ground: Your direction of travel relative to the earth
Speed over Ground: Your instantaneous speed relative to the earth
Position: Your current Latitude and Longitude, or position in the selected position grid (see Settings > Units)
Accuracy: Some measure of how accurate the GPS fix is. If you are using an external NMEA format data source, this is the HDOP. If you are using the location service, the precise meaning may be different.
Altitude: Your height above sea level, or your height above some other datum on some devices. (Note, GPS is less accurate for altitude than for horizontal position)
Time: Time of day reported by the GPS, converted to the device's selected timezone
24h Time with seconds: Time of day with seconds, usually accurate to UTC +/- 1 second.
Average Course: Direction of travel averaged over the past 30 seconds
Average Speed: Speed averaged over the last 30 seconds
Satellites: Satellite signal strength (NB, only works with external NMEA data, not from the built-in location service).
Drop Mark Button. Creates a mark at the current GPS location. You can customize the icon etc, and use a set of buttons to record the location of different types of items. Use the item context menu in Edit Layout mode to change the mark icon for each button. The name of the mark can be expanded with, date, user name, etc using the same syntax as the overlay creation templates (see Default Overlay Templates). It is a good idea to enable the "Locked" option, so that any marks you drop cannot be accidentally moved. Note that the "Add Mark" menu command places a mark at the center of the map display, while "Drop Mark" places it at the current GPS location.
Odometer: Measures total distance traveled, independent of track recording. In Layout mode you can change the name of the Odometer using the layout context menu. In normal mode, the context menu allows you to reset or pause the odometer. If you have multiple odometers with different names, then reset/pause is independent of each other. So for example, you can have a daily distance which you reset each day, as well as a total distance for a trip, or season.
Speedometer: graphical analog speedometer dial.
Compass Heading: The direction the device is pointing based on the magnetic field sensor in your device. See Compass Heading
Barometric Pressure: Data from device pressure sensor in mBar
(Note, these fields are active when you tap a mark or waypoint, and use the popup menu to navigate towards a point or follow a route.)
Distance: Your distance to the next waypoint
Bearing: Compass bearing to the next waypoint
Turn Angle: Angle between your current course-over-ground and the direction to the waypoint
Turn after Mark: When following a route, the angle between your current course-over-ground and the direction to the waypoint after the next one (helps you to plan for turns before you reach the waypoint).
CrossTrack: The perpendicular distance from your current position to the course line.
(Note, if you are navigating to a mark, or if you have not yet reached the starting waypoint of a route, then a "course line" is set up from your current position when you initiate navigation. If you are following a route, the course line is the closest leg of the route)
Arrow: Graphical indication of turn angle. The arrow is red or green to indicate how it has determined the direction.
•Red: the direction is relative to the way the phone is pointing using the magnetic compass. If this is not working you can try calibrating the compass. You can turn off the compass if the red arrow gives totally inconsistent results. Menu > Settings > GPS Settings.
•Green: the direction relative is the "COG" reported by the GPS chipset, ie, your instantaneous direction of travel. If you are not moving and you have poor GPS signals, then the green arrow may point in random directions. You need to move for it to work.
Time to Next WP: Estimate of the amount of time it will take to reach the waypoint, based on your current averaged speed and direction.
ETA Next WP: Estimated time of arrival at the next waypoint
Dist to Route End: Distance from your current position to the next waypoint, plus the total distance of remaining legs in the route
Time to Route End: Estimate of the amount of time it will take to reach the end of the route, based on your current averaged speed and direction.
ETA End of Route: Estimated time of arrival at the end of the route
VMG Parallel to Leg: The component of your instantaneous velocity in the direction parallel to the course line.
VMG Towards Mark: The component of your instantaneous velocity in the direction towards the next mark
Waypoint name: The name of the next waypoint.
Coming Up: A list of the next few waypoints in your route, with the distance to each waypoint.
% Along Route: Shows your distance along the route as a %age of the length of the route.
See also Using Marks and Using Routes
(Note the "latest track" is the track is the track you are currently recording, or the one you were most recently recording)
Logging Button: A button to start/stop recording your track
Resume Button: Allows you to pause and resume recording of a track. Note that resume will add to the end of the most recent tracklog. You can also resume recording a specific track using the context menu for the track.
Distance traveled: The length of the latest track
Moving Time: The elapsed time of the latest track, minus the amount of time spent stopped
Elapsed Time: Elapsed Time of the latest track
Time not moving: Amount of time spent when the amount of movement is less than 30ft.
Average Moving Speed: Average speed while moving (ie not stopped) since beginning of the track.
Average Speed Overall: The length of the track divided by the elapsed time between the first and the last points.
Max Speed: The maximum speed recorded, discarding anomalous spikes.
Ascent: Total vertical distance ascended along the track, based on GPS and/or Barometer readings. See Altitude Settings
Descent: Total vertical distance descended along the track, based on GPS and/or Barometer readings. See Altitude Settings
See also Recording Tracks
(Note these data items require connection to a marine instrument system, and you must activate a Professional License)
Boat Speed: Speed through the water from the VHW sentence
Apparent Wind Angle: Wind angle to the bow, from the MWV sentence
Apparent Wind Speed: Wind speed relative to the vessel, from the MWV sentence
True Wind Direction: Wind direction relative to the earth, from the MWD sentence
True Wind Speed: Wind speed relative to the earth, from the MWD sentence
Depth of water: Water depth, adjusted for transducer depth if known, from DBT sentence
Water Temperature: Water temperature from MTW sentence
Rudder Angle: Rudder angle from RSA sentence
Average Rudder Angle: Rudder angle from RSA sentence, averaged over about one minute. (use to see effect of sail trim on helm)
Engine RPM: Engine revolutions per minute, from RPM sentence. Shows both engines if two are present
Instruments / Timer
These items provide a count-down / count-up timer, designed for sailboat racing, but can be used for any purpose
(Use Tap-and-hold, Timer settings menu to configure the count-down period, or to set the count-down to a specific time of day)
Time to start: Shows the amount of time. A + sign indicates the timer is counting up, after the start
Start countdown sequence: Button to restart the count-down.
Ping Start Line Right Mark: Button to store the GPS position of a point at the right-hand end of the start line (or on an extension of the start line)
Ping Start Line Left Mark: Button to store the GPS position of a point at the left-hand end of the start line (or on an extension of the start line)
Distance to line: Perpendicular distance from your position to the start line (line is extended both ends). A negative value means you are over the line.
ETA Early/Late at Start: If you continue your current course and speed, indicates the timer value when you will cross the line. Ignores line end-points - the line is extended both ends. Shows a + sign if you are late for the start, a - sign if you are early.
(Note, device built-in GPS units are typically not accurate enough for use on the start line. An external high precision GPS is recommended)
Start-Line Bias vs True Wind: If you have a True Wind input (from the MWD sentence), you can display the angle of the start line to the wind, to help decide which end of the line is favored. (Note this does not take any current into account.)
Start-Line Bias vs Axis: Set the axis as your estimate of the wind direction, or as the bearing to the first mark, and this will let you know if the line is skewed relative to the axis.
Instruments / Axis
This section allows you to setup a reference direction, know as the Axis, and display various data items as a bearing relative to the axis. You can use it as a course-to-steer, or for monitoring changes in heading or wind. Press-and-hold any of these to setup the Axis.
Axis: Just shows you the current Axis setting.
Heading vs Axis: Shows the compass heading relative to the axis. Plus means you are steering to the right of the axis, minus means you are to the left.
COG vs Axis: Shows the GPS course-over-ground relative to the axis. Plus means you are traveling to the right of the axis, minus means you are to the left.
True Wind vs Axis: If you have True Wind (from the MWD sentence), this shows the wind direction relative to the Axis. Plus means the wind has shifted to the right, minus means it has shifted left.
Allows you to add various menu commands as buttons on the screen. Each button can be placed anywhere you like and resized to show an icon with text or just the icon.
Logo: just for branding
Map: The map display is itself a configurable item on the display. You can have more than one map on the screen to provide an overview and a detailed view, for example.
Background image: Add a customizable background image. Note that the image is not saved with the layout file. It has to be set up on each device.
Battery level: shows % of energy stored and charging status
Blank: sets an empty item
Static text: Allows you to add your own message to label things on the screen
Next: Default Overlay Templates