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zeus661

Magnetic or True North?

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I have a Garmin Monterra and Montana 650T.  I like to know which direction I am facing and have both set so I can see the compass heading.  Should I select Magnetic or True North in the settings? I am in North America.

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Posted (edited)

It's up to you.  It's good to set your devices so they agree, or set as others are in your caching group.  You may need to change settings for some puzzle caches.  Here's a thread on the subject:

 

 

 

 

Edited by kunarion
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Posted (edited)

Wherever you live you will have a declination, that is the number of degrees difference between true north and magnetic north. It can be east or west.

So with true north set you will face true north and with magnetic north set you will face magnetic north. As already mentioned it won’t make any difference for caching or most navigating.

It will become important when you use a handheld compass and paper map with your gps or if you are given a bearing to follow to a waypoint or cache, you’ll always have to work in true or magnetic readings or else convert one to the other. 

Edited by Forkeye

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3 hours ago, zeus661 said:

I have a Garmin Monterra and Montana 650T.  I like to know which direction I am facing and have both set so I can see the compass heading.  Should I select Magnetic or True North in the settings? I am in North America.

 

If you are going to hunt Field Puzzle caches which have projection calculations (go 145 steps to 256 degrees) you need True North setting. Magnetic North has no use with Geocaching.

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I keep my settings set to True North, but I have seen some Projection puzzles which required Magnetic North.

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Posted (edited)
4 hours ago, K13 said:

I keep my settings set to True North, but I have seen some Projection puzzles which required Magnetic North.

 

Yes, you need to use the 'North' setting specified by the cache owner!

 

 

 

Edited by Atlas Cached
silly autocorrect!

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It depends on what you mean by "which direction I am facing". For me, I want to know whether I'm looking towards the north star and down the Earth's axis of rotation, or whether I'm looking east or west towards where the sun rises or sets on the equinox, or whatever along those lines. So I use true north. If you want to know which way you're facing in relation to an entirely arbitrary point defined by the current state of Earth's quirky magnetic field, then use magnetic north.

 

As the last two responses have implied, there are times when what you like is irrelevant because you're following someone else's directions, and in that case, you use whichever one they used. (My big problem with that is that, for unknown reasons, whenever I hear "true north", I think of where a compass points, which is exactly wrong.)

 

By the way, it's interesting you mention being in North America. If you're in the middle of the continent, it doesn't much matter because there's not much difference in that area. There's plenty of difference on the coasts, though.

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Comparing two GPS's (Garmin Montana 650t and Garmin Monterra), two iPhones, and two oil compasses I can't get any two to point to north in the same direction.  I have calibrated both GPS numerous times also.

 

I have both GPS's set up to show me Distance to Destination (selected cache), Accuracy of GPS, To Course (which I believe is direction to cache), and Compass Heading on the map view.  My thought is if I get Compass Heading and To Course to show the same degree my GPS is pointing at the cache.  AM I THINKING CORRECTLY?

 

The problem is that both GPS's Compass Headings are off by up to 20 degrees.  Distance to Destination and To Course are almost always matching on the two GPS's

 

Any suggestions?

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Calibrate them outdoors, away from any structures, especially metal and or electrical lines.

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2 minutes ago, Atlas Cached said:

Calibrate them outdoors, away from any structures, especially metal and or electrical lines.

I did several times

 

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If you are holding them in very close proximity, one can affect the other. Magnetic sensors don't like being that close to each other.

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2 hours ago, zeus661 said:

I did several times

 

 

None of my Garmin GPSr have compasses off by 20 degrees.... Never. Maybe 2-3 degrees, certainly less than I can detect with any level of certainty.

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On 7/10/2019 at 6:39 PM, zeus661 said:

.... To Course (which I believe is direction to cache), and Compass Heading on the map view.  My thought is if I get Compass Heading and To Course to show the same degree my GPS is pointing at the cache.  AM I THINKING CORRECTLY?

To Course is not the same thing as Heading. To Course has no real usefullness in geocaching. Heading is always pointing to the cache and is what you should be paying attention to. 

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2 hours ago, JohnCNA said:

To Course is not the same thing as Heading. To Course has no real usefullness in geocaching. Heading is always pointing to the cache and is what you should be paying attention to. 

 

Actually, they should be using 'Bearing'

 

To Course: "The direction in which you must move to get back on the route. You must be navigating for this data to appear."

 

Heading: "The direction you are moving."

 

Bearing: "The direction from your current location to a destination. You must be navigating for this data to appear."

 

source: GPSrChive

 

Edited by Atlas Cached

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Posted (edited)
On 7/13/2019 at 11:06 AM, Atlas Cached said:

 

Actually, they should be using 'Bearing'

 

Bearing: "The direction from your current location to a destination. You must be navigating for this data to appear."

 

Oops - yes, I meant Bearing. Although Heading and Bearing are two of the data fields I have on my Garmin map screen. 

Edited by JohnCNA
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