Heading Vs Bearing In Gps Context?

[+markp99]

Can someone clarify the terms "Bearing" and "Heading" in GPS context.

 

I had a recent cache hint say, take 20 paces bearing 320 deg from from the obvious landmark. I found the cache by sweeping a 20-pace radius. A bit crude, but effective.

 

I've seen this type direction before. I am confused on the term/method. Looking at my GPS (eXplorist500), should I have oriented myself with 320 at the TOP of the display, regarless what the red arrow was doing?

 

I realize direction/orientation with a GPS is only valid while moving, but I'm just hoping to understand the concept.

 

Would the approach be different with a magnetic compass?

 

Thanks

[+sbell111]

Assuming that you Explorist has a built in compass, I would say that you would simply point it at 320 degrees and go (ignoring the magnetic v. true issue).

[+markp99]

More clarifiaction, please:

 

Is "Heading" the same as "Bearing"?

 

On my GPS should 320 be displayed at the top of the "dial", ignoring the GPS red needle which is pointing at the coordinates.

 

mark

[+tozainamboku]

Bearing is the direction to the destination or target. Heading is the direction you are traveling or facing. Both are measured in degrees from North. A cache using heading or bearing in a hint should tell you whether to use True North or Magnetic North. Some people will use magnetic north since they want you to use a magnetic compass. Most GPS units can be set to use either magnetic north or true north. Unless the unit has a built in compass (e.g., Explorist 600) you need to be moving for it to detect direction. Most units also have the capability to project a waypoint by entering bearing and distance either from your current position or from another waypoint.

Edited July 6, 2006 by tozainamboku

[PCFrog]

I not 100% positive on this but if I remember right your bearings is your location or spot you are at. An object can also have a bearing as well. So, if you traveling north something like a tree can be at bearing 220. Heading is exactly that, the direction that you’re heading or an object is.

 

My question would be is that bearing 320 from magnetic north or from cache direction based upon the landmark?

 

Please note been long time since I actually used a compass and pulling this information out of my grey matter that been covered with webs.

[+Jango & Boba Fett]

Technically a bearing is a direction to, given as degrees/grads/radians relative to Grid North (the one you would measure off your USGS or Ordnance Survey topographic map). If qualified as a magnetic bearing then it would be a direction to relative to Magnetic North (which is of course on the move so ideally a date should be given so that the magnetic declination can be accounted for. In practise based on the using compass directions most caches I've come across appear to be using magnetic bearing when they say bearing.

 

If you refer a direction to as being relative to true north then this is an azimuth, but I wouldn't expect to come across that term too often unless someone is trying to make a nautical or aeronautical point.

 

Since coming across my first offset multicache (It was changed to a straight multi a month ago ) I've loved the idea and having tried it out on a single stager of one of my own caches I discovered that what is in essence very straight forward (walk so far on this bearing) is in fact very hard to to do.

 

Have a look here and you will see an example of what I mean. The cache is a Shurlok in a urban setting, so it looks like someone has left their bicycle lock behind, but once you have the combination it will open the little key compartment which acts as a microcache. Great fun!

[+RockyRaab]

Bearing is the direction from you to the target, regardless of your own direction of travel.

 

Heading is your direction of travel, regardless of the bearing to the target.

 

Clear?

 

Example: Your GPS says the cache is on a bearing of 180 from you (south). You might be facing or slowly walking east, or west or north, but the BEARING to the cache is still south, despite where you are currently HEADING.

 

Now, you start walking south. For the moment, both the BEARING and your HEADING are the same.

 

As you get closer, you continue walking on a due south HEADING but you miss going directly to the cache because you angled off a wee bit. The "GoTo" needle nows swings over until it is pointing east. Your heading did not change, but you have a new bearing. If you walked far enough, the needle would point almost straight back behind you, and your bearing would have swung from south through east to north, even though you never changed your heading of south.

 

Still clear - or no?

[+markp99]

Yup, a bit clearer.

 

Only fuzzy part is where/how do I read the bearing on my GPS unit. I see the compass dial and the arrow points to the current coordinates. Is my current bearing the number at the top/front of the dial?

 

Thanks!

[+Mudfrog]

I've seen this type direction before. I am confused on the term/method. Looking at my GPS (eXplorist500), should I have oriented myself with 320 at the TOP of the display, regarless what the red arrow was doing?

 

Yes! Once you found the obvious landmark then you should have headed 320° for the 20 paces using your GPSr or a regular compass. You would watch your compass ring now, keeping that 320° at the top. Either turn off your "go to" or just don't pay any attention to the arrow at this time.

 

Heading is the direction you are going. Bearing is the direction in which the object is from where you are now.

 

Being magnetic or true wouldn't make much difference on this one since it it so close. You would need to make sure you were using the right variation if you were trying to find a point farther way as error would be greater.

Edited July 6, 2006 by Mudfrog

[+CJOttawa]

I not 100% positive on this but if I remember right your bearings is your location or spot you are at. An object can also have a bearing as well. So, if you traveling north something like a tree can be at bearing 220...

 

You're describing a "relative bearing" - e.g.: if something is directly, 90-degrees to your left, the relative bearing is 270-degrees. (it's measured as if your nose is or the longitudinal axis of your vehicle/GPSr is "zero" degrees)

 

This does not necessarily coincide with an absolute magnetic or true bearing which is measured against magnetic or true north.

[+FamilyDNA]

Last weekend we came across a letterbox hybrid with directions we were unable to complete. It told us to "walk approximately 410 feet, bearing 200T." What is the "T"? I thought bearings were in degrees? Our little group had varying opinions as to what this meant. As we were all tired by that point we just gave up and went home.

[+Jango & Boba Fett]

Last weekend we came across a letterbox hybrid with directions we were unable to complete. It told us to "walk approximately 410 feet, bearing 200T." What is the "T"? I thought bearings were in degrees? Our little group had varying opinions as to what this meant. As we were all tired by that point we just gave up and went home.

T = True so 200º relative to true north which is more or less southsouthwest (222º 30' 00"), so switch your mapping preferences from Magnetic North to True North and stomp off 125 metres, and there she should be.

 

Chae

[+ar_kayaker]

Yup, a bit clearer.

 

Only fuzzy part is where/how do I read the bearing on my GPS unit. I see the compass dial and the arrow points to the current coordinates. Is my current bearing the number at the top/front of the dial?

 

Thanks!

 

There is an easy way to go to a place 320 degrees 20 paces away from where you already are without a compass, a lot of diddling with the bearing ring, projecting a waypoint, etc.

 

If you are at the first stage of a multi and your GPSr is reading zero feet to the cache just start walking roughly the direction you think the cache is in. (If you aren't at a waypoint already use the "mark" funtion to create a temp waypoint where you are starting from and "go-to" it.) When you get to 140 degrees, 50 feet, you are there because that will be the direction and distance back to the starting point. (140 + 180 = 320, 50 feet being 20 paces x 2.5 feet per pace, the walking stride of an average man over uneven ground)

 

Anytime you get to a cache-stage that says go XYZ degrees for ABC feet just add (or subtract) 180 from the direction and go until your GPSr says you are the right distance. Saves a lot of reprograming in the field.

 

AR_kayaker