Global Compass - how do they work
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- เผยแพร่เมื่อ 2 มิ.ย. 2024
- While standard compasses may experience limitations such as needle dragging and erratic behaviour in regions with strong magnetic dips, global compasses have a separate magnet and north-seeking pointer to ensure consistent and reliable performance under various magnetic conditions.
Standard Compass:
• In a standard compass, the North Seeking Pointer is typically a magnetized strip or disk made of a ferromagnetic material like steel.
• The magnetic needle is rigidly attached to the base or housing of the compass, typically by a pivot point.
• As the compass moves towards the magnetic poles (either the North Magnetic Pole or the South Magnetic Pole), the magnetic field lines become more vertical, causing the needle to dip or incline.
• When the needle dips too far due to the strong inclination of the magnetic field lines, it may drag or rub against the base of the compass housing. This friction can impede the smooth rotation of the needle and affect the accuracy of direction readings.
• Additionally, in extreme northern or southern latitudes, where the magnetic field lines are nearly vertical, standard compasses may exhibit erratic behaviour or become unreliable due to the excessive dipping of the needle.
Global Compass:
• In contrast, a global compass is specifically designed to mitigate the limitations associated with standard compasses, particularly in regions with extreme magnetic inclination.
• In a global compass, the North Seeking Pointer is attached to a small magnet in a unique manner that allows the magnet to tilt or dip without significantly affecting the orientation of the Pointer.
• By allowing the magnet to dip freely, the global compass can compensate for the vertical inclination of the magnetic field lines, ensuring that the Pointer remains relatively stable and accurate even in regions with strong magnetic dips.
• This design feature minimizes the risk of the needle dragging against the base of the compass housing, thereby maintaining smooth rotation and precise direction readings.
• Consequently, global compasses are better suited for navigation in diverse geographical locations, including polar regions, where standard compasses may struggle due to magnetic anomalies and extreme magnetic inclinations.
Every video I think to myself, "Man I'm glad I found this channel".
What a wonderful world, ooooohhhh yeeeeeaaaaahhh
That's a lovely comment!❤
Some people are born to teach. I’m grateful to encounter them.
That is fascinating, again you teach us about something that we knew nothing about and keep our attention because its so well presented. Thank you.
Completely not what I expected the difference to be. Many thanks for the explanation.
Excellent as usual, thanks. Can't wait for the quantum electrodynamics talk. Best teacher I ever had.
❤
The Map Reading Company, Wow, this made my day brighter! Thank you!
Damn man, I have NEVER seen a video about something I didn't know I was interested, catch me so hard in the first 35 seconds. Sir, you are hipnotic on another level.
Thank you.
Was in the US Army did land navigation, but never was taught about that.
I live in New Zealand and it is very difficult to find a compass where the southern end of the pointer doesn't scrape. Even proper outdoor shops frequently sell compasses that have been balanced for the northern hemisphere (with a northern hemisphere DIP angle). When I try to tell them they look at me like I come from Mars. I go back to the shop a year later and they are still selling them. Using a compass with the wrong dip angle is incredibly annoying because you always have to monitor if it is scraping and thereby giving you a false bearing.
Enjoy your videos, any chance of one about the wonderful, but now discontinued, Silva 54 with the miniature sighting prism built into the housing. I used one in Antarctica to sight in a row of glacio poles, on a bearing. We swore that with care you could sight to 1/3 of a degree. Cheers.
There's a good reason folk are working in shops. Shop assistants are notoriously bad listeners and basically slaves to proprietor's directives. They just want to shift stock.
Go to a ships chandler and try there. Ships of course, go everywhere and move about doing it.
@@markbernier8434 Quite right. Compasses are swung regularly and larger ports will have agents equipped to do the job. Most modern small boat compasses are fluid mounted globes rather than cards or needles.
The Silva Expedition S has a sighting mirror, which is supposed to do the same thing. I haven't used either, so I don't know, though. But Silva Expeditions is what we always used when orienteering in school.
I've had quite a few different compasses over the years...but if you really want accuracy in a small package I bought a sighting compass made by Suunto. I know most compasses have the sighting feature but this one was different...The factory specs were different too. The factory claimed accuracy 1/3 of a degree.
I bought it for doing rough survey work...the price wasn't all too bad...i wasn't expecting it to replace a transit...but it usually did. Suunto KB-14/360R OH, AND IT SAYS GLOBAL ON THE DIAL.
WHAT YOU CAN'T SEE IN THE FACTORY PHOTO IS THE VIEW INSIDE THE SIGHT WINDOW...HOW YOU USE IT IS KEEP BOTH EYES OPEN.
Incredibly effective speaker and your props and visuals are outstanding. GREAT work!!
I discovered this myself, almost 30 years ago, when I was in college studying for an electrical engineering degree, and as a project developed a digital compass, which gave its best results when tilting down on the north end.
I never knew that.
Every day's a school day.
Thanks.
Thank you for a great explanation of a little discussed area of compass behaviour. I liked your wooden lecturing aids.
well I raised a question directly on this a couple of weeks ago, maybe that's not a coincidence to get a new video to directly answer it ... either way, thank you ... all very clear as always!
The other advantage of many global needle designs is that they can be accurately read while running, canoeing, etc thanks to the stable, fast-settling needle (1-2 seconds or less)
SUCH A GREAT INFORMATION, thanks so much, now I understand. Bests regards from a Venezuelan follower in Panama!
I like the little spherical compass that is suspended in liquid.
That was very well done. Nice and simple, and no useless music!👍 Good use of 'clunky' props.
The best explanation of the differences that I’ve ever heard.
Now I want to know why lanyards are always to short- bugs the crap out of me.
It's amazing. I only hike along trails with gps, but your videos inspire me to try out this method and off the trails. Of course in a safe way, start in a familiar small forest:) Thanks for sharing your knowledge
I started using a compass when I was a Boy Scout more than seventy years ago. I don't hold the compass flat (or horizontal). I hold it so that the needle moves freely. On rough terrain, what looks like flat may not be.
The inclinometer is there to measure slope angle. Very useful if you're on a snowy mountain or hill and want to know whether you're in an avalanche danger zone. Plus it's easy to just print a few extra lines on the compass base, and you've got an extra feature to list on the packaging ;)
Wayne, brilliant course at the weekend near Hathersage, I learned a lot but also realised I need to learn a hell of a lot more. I took your advice and bought an expedition 4 instead of a global. See you on the gold award but not after loads of practice first.
Thanks again
Glyn
Hi Glyn, nice to meet you all over the weekend. I've sent you an email this morning with the results. See you in Malham next year then (on the Gold course)
Excellent presentation, clear and demonstrative. Cheers.
Well... That's news to me! Thanks for the clearly understood explanation, as always!
Great video. I thought I knew something about a compass, but this was new to me. Thanks.
I just learned a number of interesting things, thank you!
This is an excellent explanation. I wish I'd known this stuff 30 years ago when I joined the army. Never-mind, in my 20 years in I never got lost.
Thank you for your presentation!
Aaah, excellent. I’ve seen global compasses advertised but never knew principal. Thank you.
I learn new things every day. Thank you.
Interesting . Very well presented . I learned something today . Good Job .
Thank you for your explanation .
A lot of good information.I think I knew some of it, but it was a great review.
That was very elaborate!
Good video. Thanks.
very nice presentation- good usable info :)
Tx for through video...thanks for explaining it so well
Great video...👍
Very informative.
THANKS. was aware of the issue but didnt know how the work around was achieved
Very good!
Although I already knew about this material, I was curious on your presentation. Waffling aside, you had good visuals and explanations... things I wish I saw back when I learned about it. Really useful video for any newbie. Good job! Only downside, was waiting for you to break out the thermos for a nice cuppa while sheltering in the dell!
What's your favorite type of tea?
I take a guess - Yorkshire English tea😅
Fascinating for a 62 year old guy. I never knew or thought about this.
i have never needed a compass cuz I’m a city boy, haha, and I stumbled on this video randomly. And well, shoot! Heck! I think I’d almost just as soon purchase a high quality global compass and spend the money once. And keep it like a piece of jewelry or something. Haha. Even though I’ve no plans to go from America to Tierra del Fuego any time soon. Anyways, so cool! I learned a thing!
Excellent video sir. I am always surprised at how few people carry a compass into wooded areas let alone know how to use even the basic functions of the instrument.
Didnt know about the compensating weights in a compass, but makes perfect sense. Interesting info about global compasses though - ! 😊
Very interesting video, thanks for sharing.
Since very long time it was a big mystery to me how such a global compass functioned. The reason why we need in certain places a compass with a global needle was very clear for me, but not how it works or be manufactured.
I own two compasses, a plate compass is a normal compass, my bearing compass is a global type. I see the difference between both by their needle but i had no idee what really was the difference. Now i know it. Is this something i really need? No, i don't but it's very interesting and i am happy know to now it.
Not only once again was brilliant, but I didn't even know there was such a thing. I can now plagerise you and impress my friends with how brilliant I am, as if they didn't know already.
Brilliant, educational and enjoyable to watch. Thank you. If the difference is only the pointer separated from the magnet from product manufacturing perspective, why brands not make global compasses the standard product, rather than charging so much higher prices for these compared to the hemispherical ones.(Btw pls do explain quantum electro dynamics…!)
Very interesting ❤
Yes. I did find it interesting. Very interesting, actually. I have a relatively cheap orienteering compass that currently suits my basic needs. In the future, I'd like to invest in something that is more robust so that my clumsy self can't damage easily, and I can rely on to be accurate. It won't be a global compass, but still, I learned a lot from this video. Thank you.
A few years ago, Suunto changed to a simplified version of their Recta-pattern global needle. The original version is IMHO much better. The Recta patent needle swings more freely on its jeweled bearing in the center of the hub. The new design has a plastic needle that seems to drag on the bottom of the compass vial, even at slight angles.
Amazing!
I have a good quality "global" compass with inclinometer. It's only plastic but is a good one which cost me over $100. Most compasses are indeed region specific and don't work very well in such circumstances.
Very interesting. By looking at the dip of the magnet you get also an idea of the latitude.. (if you really get lost..)
Excellent video. You are an exceptional teacher and a decent carpenter. Fortunate to have found your channel. Why are inclinometers useless?
They are useless to me as I never use them. But there are some people who they help. Mind you if you know how to use a compass then they're not needed as you can get the angle of a slope quite easily.
I’ve shown how to do this in this video: th-cam.com/video/4LR14ue0Gz8/w-d-xo.html
@@TheMapReadingCompany I found the inclinometer video after asking the question and immediately understood your comment. Determining slope with only the compass was a “why didn’t I think of that” moment. Thank you for the reply and the excellent videos. And I do enjoy your waffles.
NIfty. I've been wondering about that, being in the market for a global compass for my nephew who is an Army cadet and also likely to travel overseas when he is older.
Thanks for this explanation! (And the carpentry did more than a Blender animation would)
I guess many viewers are interested in subtitles of magnetism and don‘t mind few extra details. They may like Paul M Sutter’s AskASpaceman episode about magnetism.
That cleared up the difference.
Great explanation. So can a global baseplate compass tolerate a greater angle of baseplate tilt than a northern hemisphere compass when used in the UK?
Yes - that's why a lot of people buy them
So essentially. the pointer in a global compass is mounted on a gimble. Sailors will appreciate that.
Thank you for another great video. Sadly, one reward may be a very stupid question. Does the lengty of the needle, seperation of north & south poles affect precision ?
I've always thought a longer needle with the north end further from the south makes a difference. Granted size does not affect a spirit level much so I could be wrong.
Thanks for your work! Please can you mention, the excellent Ordnance Survey map of Roman Britain, with Roman towns and roads overlaid on a faint background of modern British roads..?
Super !
Lovely video.
90% of the world population lives north of the Equator.
You are amazing, thanks for making this video.
I have the Suunto global compass and wasn't too sure how it is manufactured, now I know.
I am based in Melbourne Australia and 3 years ago I bought a Cammenga 27 for South Hemisphere and the South pointer needle was still dipping down. So, I disassembled it and added some brass weight at the north pointer and all fixed.
The following year I bought another and the packaging clearly shows South Hemisphere balanced and still dipping. I contacted Cammenga and they insisted it is correctly balanced. I doubt it.
Anyway, what I am saying is that the Cammenga can easily be balanced by anyone depending on the the region they are ie 1-5.
Cheers
Is there a kind of compass or similar device for visualizing magnetic field lines in 3d? Like a compass that wouldn't just point north and south but up and down as well (fluidly).
I found a phone app once that gave xyz coordinates and this was close but less intuitive than I'd like. I've got some theories on storm cell rotation and relative effects on local magnetic fields I've been wanting to test.
I got the circular magnet with a plastic pointer just before an advertisement.
Thank God.
This was a great video, but it would have been better if you had shown us at least a picture of an actual global compass next to a conventional one. Or was that Suunto a global compass? I mean, what does one look like? How much more do they cost?
I bought my Silva brand compass in Sydney Australia. Will it be accurate in the UK?
Probably not if it is marked MS (Magnetic South), you will need an MN (Magnetic North)
Nah... gimmie the quantum eletrodynamics yadda yadda video. I demand it!❤
So would it be good to just get a global and be done with it? So no matter what or where you’re not gonna have a problem or if I’m in the northern hemisphere is I better to have one of those? Would it be more accurate in that particular area or would both be just as accurate as the other? Very intriguing and love your videos.
I have learnt a few things from this video and for once it was not from your rambles LOL, Thank you for these videos.
What is the best way to ask you questions?
Channel members can ask as many questions as they want on the community page - so if you would like to join that would be great 😊
th-cam.com/channels/F6JMjE4LM3nuWhaiLjLuOQ.htmljoin
Or just ask here (not everyone can afford to join a TH-cam channel) and if I have time I'll try and answer.
Excellent video! Is there any type of compass that would be usable nearby iron, which of course can impart an infuriating magnetic field if its own.
A solar compass . An Astro compass. A polarising lugh compass. All unaffected by magnets.
That was a complicated thing really well presented. I wouldn't be too self critical of your woodwork skills. Those were quite excellent demonstration models. I cant see why globetrotters cant buy a separate compass for each zone They are light enough and cheap enough. Boys Toys probably.
Love your Videos, have small question, see with global compass can it get demagnetised.
All compasses can become demagnetised.
@@TheMapReadingCompanyMy global compass got demagnetised in the hold of an aeroplane. Is it possible to remagnetise a global compass? Thanks for the interesting video.
I think there's a little bit wrong here? The only compasses I have are military lensatic compasses and the magnetic part is embedded in a glass plate massive enough that while it can still turn the pointer, it isn't strong enough to incline the pointer to where it will ever touch anything, even with pretty strong external magnetic field forcing it down.
IN AERONAUTICAL CHARTS THE MAGNETIC FILD LINES ARE CALLED ISOGONS, AND THEY CHANGE A FEW DEGRES EACH YEAR, BUT IN THES CHARTS YOU CAN SE THE CORRECTION ANGLE, FOR A PRECISE NAVIGATION
IN OTHER WORDS, YOUR COMPASS IS NOT REALLY POINTING TO THE NORT UNTILL YOU CONSIDER THE CORRECTION ANGLE PUBLICHED IN THIS AERONAUTICAL CHARTS.
Fantastic explanation. Is there any issue around reduced leverage from the smaller radius disk of a global compass vs the longer arm of a non-global compass needle?
I like that question 😊
In “some” cases the magnet in a global compass has either the same or more mass than the longer magnetic arm in a standard compass.
BUT it has to be remembered that the mass (or size) of a magnet does not directly affect its susceptibility to the Earth's magnetic field - although bigger compasses have room/space for more magnetic material. The strength of a magnet's interaction with the Earth's magnetic field is primarily determined by its intrinsic magnetic properties, such as its magnetic moment, material composition, and magnetization.
So (very basically) if you make a better magnet, with more aligned magnetic domains and greater magnetic flux density, it will exhibit a stronger response - in our case spin around inside the compass.
Don’t forget that in a standard compass the arm just needs to turn itself but in a global compass the magnet has to turn itself and also drag around the arm, so it needs to react (to the earth’s magnetic field) slightly more.
So, and I'm guessing here as compass manufacturers are VERY protective of their intellectual property, I would say that the central magnet in a global compass is just made of better magnetic material with a stronger composition.
@@TheMapReadingCompany Thank you! That answer makes perfect sense. Thank you for that explanation.
Could you explain what the magnetic field is made of?
Also, where do the compass points if you at at the north pole? Like does it flip entirely at some point if you cross it?
A magnetic field isn’t made of “something” it just “is”. You’ll need recall your school physics lessons and then you’ll remember that a magnetic field is made “by” electric charges which are moving but they are not made “of” something.
Do you remember vector fields from your school days ? A school teacher who wanted to explain it so kids can understand it would say something like, a vector field is something which changes the way space works in a specific area. Object within this area will behave in a certain as they are being influenced by the vector field. For example a compass needle in the earth’s magnetic (vector) field.
Hope this helps
The nortpole is wandering. What is the offset from Pole Star north.
Varies continually. Check with Nautical Almanac. Pages 274 - 276 in current edition. Can be up to one degree off. Mariners may routinely check the run out. Also use sun at sunrise and sunset to check compass error. Its a daily routine in some vessels. (You can google Check Gyro Error by Solar Amplitude to get the method) Of course gyro is unaffected by changes in earths field but needs regular checking anyway .
Note: it seems that global compass are also less precise (according datasheet of some of manufacturers, iirc 3 degree vs. 1 degree). But the annoying part: shops rarely tell you which version you get (also Silva UK shop did the same error). Considering the global trade I'm wondering if we get really a Northern sector. Is there a way to check, without going to very north places?
On a Silva compass turn it over and you will see 4 letters. The 2nd two letters are product batch codes (when they were made, etc). The 1st two letters are the magnetic zone for which the compass is intended to be used:
MN (Magnetic North), MS (Magnetic South), ME (Magnetic Equator).
What will a global compass do at the north or south pole?
You can't use a compass at the magnetic South Pole as all directions are north, same with the magnetic north pole where all directions are south. It gets stranger if you are at the geographic south pole as the magnetic south pole is out in the ocean, around 1,800 miles away towards Australia. In the Artic and Antarctic I’d probably use a GPS.
@@TheMapReadingCompany I've flown in the arctic a bunch, in the days before GPS. Astro compass is your friend. A good watch is also very handy when in an area with 24 hours a daylight during the summer. If you know what time it is, then you know what direction the sun should be, and you can use that to adjust the gyro.
Friend: Whats that single spinning hand on your compass?
Me: Its an inclinometer.
Friend: Whats it do?
Me: My compass has an inclinometer.
Where was this filmed? Millstone Edge or Burbage South?
Millstone Edge
Ive been teaching "compass related activities" for 20+ years and didn't know the answer to this. Excellent job. Why do I buy a compass with an inclinometer?
So you can measure surfaces in 3d space for geological mapping. At least that's one use.
@@Eragon954 I used to be a caver, and Brunton compasses (pocket transits, I believe Brunton terms them as) were and maybe still are used commonly in cave mapping because of their precision and their built-in inclinometers.
Отличное видео! Спасибо!
Подскажите зачем на компасах делают шкалу? На базовой плите, рядом с линзой? 1:24 хорошо видно две такие шкалы? Они начинаются на отметке 10 и соединяются в отметке 0.
They are Roamers - used to measure distance. 1:24 means that you can use that roamer with a 1:24,000 map.
Спасибо большое!!!
First time I've seen somebody draw the Earth with the North pole up. All of this time I thought all compass manufacturers had the South pole of the magnet in red and the North pole in white.
I have always been amused that the North magnetic pole is a south magnetic pole and visa versa.
Cool, I didn't know that. I'm not sure I'll ever use that knowledge except to drive my friends bonkers. I'll keep my Walmart compass
I did not find this interesting, it was fascinating!!
the old style but bulkier sphere in liquid compass didnt have this problem?
Could you do a video how ship compass work?
Sorry I only do Land Navigation videos
Inclinometer - use it to measure the dip slope of the rock strata. Geology students’ mapping tool.
Interesting information and a good video, as always. Keep up the good work 👍
Are the Global housing filled w/turpintine?
All the global compasses I have are oil filled. But there are some others which aren't.
@@TheMapReadingCompany Thanks for the prompt reply.
Do all planets have magnetic north and south poles?
Apparently not. Mars and Venus don't seem to. Our moon doesn't either.
@@moorejl57 All these nutjobs seem to think God did it. He should have put magnets in everything. Perhaps NASA should drop a great big magnet on the moons south pole?
👍
Why does a bar magnet not dip in the North?