GPS Data Field Definitions

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Data Field Definition
Altitude Current altitude.
Avg Speed Trip Odom / Trip Timer.  Be careful with this one; if you fail to reset the trip values at the beginning of your journey, this value could be very deceiving.
Bat Timer Amount of time that the GPS has been on, using the current set of batteries.
Bearing Direction of the next waypoint.  (Dependent on your definition of ‘north’.  See Course for more info.)  If there is no waypoint, this field is blank.
Course Actual compass angle that you are traveling.  (e.g. If you moving southeast, the Course will be 135°.)

This value is dependent on your definition of north.  ‘North’ could be true north, magnetic north, grid north, etc., etc., depending on the GPS setting.
Dist to Dest Summary: Given a route, it is sum of the distance of all of the legs, starting with the distance from your current position to the waypoint designated as Wpt (next).

Full Definition: Distance to the final waypoint, based on the sum of the distances between the intermediate waypoints (i.e. sum of the legs), NOT the absolute distance (i.e. straight-line distance) to the destination.  Blank if there are no waypoints.  The 1st distance being summed is the distance to the nearest waypoint, IF you are stationary.  If you are not stationary, it is the distance to the waypoint that you are moving toward.

Example: Say that you are between the your starting position (START) and the 1st waypoint (WP01), and are taking a break.  You pull out your GPS to determine how much further you have to travel.

Scenario 1: If you are at the halfway mark between START & WP01 or beyond it, the 1st distance being summed will be the distance from your current position to WP01 (assuming WP01 is the nearest waypoint).

Scenario 2: If you haven’t made it to the halfway mark between START & WP, the 1st distance is from your current position to START; thus your total distance will exceed the length of your route.

The 2nd scenario matches the 1st scenario if your GPS had been powered up the entire time, or you were moving toward WP01 when you turned it on.
Dist to Next Distance to the next waypoint.  Blank if there are no waypoints.
ETA to Dest Time of day when the final waypoint is reached, based on the Speed value.  As with ETA to Next, it is blank if:
  1. There are no waypoints, or
  2. Bearing is not pointing directly at a waypoint, or
  3. Speed is 0.
ETA to Dest = Time of Day + Time to Dest.
ETA to Next Time of day when the next waypoint is reached, based on the Speed value.  Blank if:
  1. There are no waypoints, or
  2. Bearing is not pointing directly at the next waypoint, or
  3. Speed is 0.
ETA to Next = Time of Day + Time to Next.
Max Speed Maximum value of Speed during the current trip.
Odometer Distance traveled.  This can be reset independent of the trip odometer.
Off Course Shortest distance from the current position to the line between the previous & next waypoint.  (Representing Off Course as a line on a map, it will be perpendicular to the line connecting the waypoints.)
Pointer Same as Bearing, but displayed graphically as an arrow.
Speed Instantaneous speed over 2 dimensions.  Altitude is not factored in.
Sunrise Time the sun rises, given your current position.
Sunset Time the sun sets, given your current position.
Time of Day Time, as in what your watch says.  Make sure the offset is adjusted properly for your longitude & DST.
Time to Dest Time required to reach the final waypoint, based on the Speed value.  Blank if:
  1. There are no waypoints, or
    2. .
  2. Bearing is not pointing directly at the next waypoint, or
  3. Speed is 0.
Time to Dest = Time to Next + sum of the times between the remaining legs of the route.
Time to Next Time required to reach the next waypoint, based on the Speed value.  Blank if:
  1. There are no waypoints, or
  2. Bearing is not pointing directly at the next waypoint, or
  3. Speed is 0.
Time to Next = Dist to Next / Speed.
To Course The direction that you must turn, in degrees, that will put you on the line connecting your previous waypoint with your next waypoint.  It will point you to either the point on this line closest to your current position, the next waypoint, or somewhere in between.
Track Direction from your starting position to your current position.

Example: Suppose you are hiking, and you started from where you parked your car.  Assuming that car is northwest of your current position, your Track direction is 135° (i.e. southeast).
Trip Odom Distance traveled during the active trip.
Trip Timer Time spent moving during the active trip.
Turn Relative angle to the next waypoint.

Example: If you are traveling northeast, and your next waypoint is actually west, Turn will be L135.  You must spin around 135° to your left, to head for the next waypoint.
User Timer Elapsed time of the user-set timer.
Voltage Voltage level of the batteries.  (The car battery if that is the power source.)
VMG Velocity Made Good.  Instantaneous speed that you are moving toward your destination.

Example: If your Bearing is either 60° or 300° and your Speed is 4 mph, your VMG is 2 mph.  (cos(60°), or 0.5, multiplied by 4 mph.)
Wpt (Dest) Name of the destination waypoint.
Wpt (Next) Name of the next waypoint.