GPS Navigation

[commando]

Navigation.jpg

This picture clarified a misunderstanding i had with my GPS settings, which as you know has many selectable options.
and i didn't pick it up until i had no waypoints selected as my forward direction cursor was always set on
either Course, Bearing or Heading which is fine until no waypoints is the selected format, that's when the GPS dropped
off all references to direction or the ones it displayed were actually misleading or incorrect, until i figured out i should
have been using Track with no waypoints to aim for accurate travel direction as that was the direction space i was moving through.

Interested to hear further opinions about it, but for me it changed my thinking and what options to select on a GPS.

[keithy]

Not sure what you mean, but in some instances, the terms may be confusing. For example, in your image it appears to relate to aviation.

For simplicity in using a GPS for bushwalking/walking:

Track = your current path. In your image, it will be the path that your GPS has recorded after you left the point KABC.

Course (Route) = the proposed track you are following - made by connecting two or more waypoints. On some GPS units, Course direction will mean the direction back to the proposed Route or track you are following.

Heading = the direction your GPS is pointing. In aviation, such as shown in your image, the heading is the direction the nose of the aircraft is pointing at. In crosswinds for example, the aircraft may point at a different heading direction compared to the direction it is flying.

Bearing = the direction to your next marked waypoint.

Now, in your image example, the Course is the intended path, or the Route. If there was no wind issue, the Course, Track, Heading and Bearing should all equal each other.

With wind affecting the aircraft, the Track shows the flight path of the aircraft having left point KABC, south of its intended Course. The Heading shows the direction the aircraft is pointing at, and the Bearing shows the direction the aircraft is flying to get back on course to its intended waypoint KXYZ. So the pilot of the aircraft would note that the destination to KXYZ is 20° to the right (starboard).

Here are some examples, from two of my GPS units.

First from a Non-mapping Garmin Foretrex. The Heading 281° is where my Foretrex unit is pointing as I hold it level. The Bearing 092° is the direction I need to head to arrive at my saved waypoint.

Garmin Foretrex Bearing Heading.jpg (54.96 KiB) Viewed 4038 times

Next is the same from my Garmin Oregon. A more complex mapping unit, the Oregon display can be changed to show different dashboards. In my case I have set the compass page to display Heading in degrees.

Garmin Oregon Bearing Heading.jpg (36.99 KiB) Viewed 4038 times

So in this example, the Oregon unit is pointed towards 269° Heading. The Bearing of 79° is the direction towards my waypoint. The Course is the same, as I only have a single waypoint marked. If I had created a Route, the Course would show the direction to back to the Route I created, if I had deviated from the Route.

In addition, note there is a slight fragmented line in the main purple arrow. If I deviated from the Course (Route), the middle segment of the pointer line would move to in the direction I went off-course. In this case, the Bearing pointer would still point to the destination waypoint, but the Course pointer would point back to the Course/Route that I deviated from.

If you don't have a forward waypoint set as your intended Route on your GPS, you will not see any directions displayed under Bearing or Course. If your GPS has an internal electronic compass (as my Oregon does), you will still see the Heading direction when stationary.

[commando]

If you don't have a forward waypoint set as your intended Route on your GPS, you will not see any directions displayed under Bearing or Course. If your GPS has an internal electronic compass (as my Oregon does), you will still see the Heading direction when stationary.

Exactly this was my findings... the screen was blank and the awakening happened, it was getting dark and cold and i needed an exit out of the gorge
it gets complex with a blank screen and fading light to fiddle with settings.

I like to do off track walking with a Garmin GPS 72 not all forward directions made sense in gullies or scrub where you have to traverse a gorge or river
but with Track selected it all matched the mapping and direction where i wanted to go. The track selection is not an obvious selection choice but aviation
uses it a lot, hence the example picture.

Sometimes navigation clarity is better suited to where you have come from rather than where you want to go to, its just a different perspective.

That feeling of being lost or disoriented never really leaves you after the first time it happens.

The evidence of where you have come from has more gravity than an imaginary evidence of where you are going to, hope this make sense.

[keithy]

Ok that makes sense with that unit. The GPS 72s were non-mapping models without an electronic compass. Good units at the time.

When you are stationary and without a waypoint selected, it will only give you your current position. And if your map screen is blank, that can be disconcerting.

I used to prepare with paper maps, marking waypoints on my older non-mapping gps units.

Some of my older units used to have this function where you could project a waypoint in the field. Not sure the GPS 72 has that feature. Projecting a waypoint meant that in the field, you could spot a point on the opposite riverbank, enter the bearing, and approximate distance from yourself, and it would mark a waypoint that you could use to navigate to, even after losing physical sight of the waypoint.

For older non-mapping GPS units, even if you are using it in conjunction with paper maps, I have found it good to refer to the Track log. In fact, most of the units had track logging automatically enabled once the GPS acquired satellite signal.

The only downside was the memory issues of older models. They had limited track logs and when the memory was full you could either wrap around overwriting the oldest track logs, or stop recording. Newer units don't have this issue with larger memories and fewer track log limitations.