AusNav #1 - True North, Grid North, Magnetic North and Magnetic Variation
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- เผยแพร่เมื่อ 30 ก.ค. 2014
- Greg explains the differences between True North, Grid North, Magnetic North and how Magnetic Variation or Magnetic Declination fits in. We'll go through some examples of how to convert from one to another.
Sorry for the over-driven audio quality on this video.
If you like the video, please give it the thumbs up. I welcome any feedback, comments or suggestions you have for upcoming videos.
Thank you for sharing this!
Greetings from Brazil!
I've always struggled with this subject and have to thank you a million times for making this video!
best video ever abut three Norths and declination , explain every thing
Greg, thanks for such a comprehensive explenation.Very helpful and made so simple to help us understand.
Thanks for the feedback Roger. Glad it was useful to you.
Great video. I am currently in the infantry and needed a slight refresher on land nav. Another great trick to know whether to add or subtract from Magnetic or Grid, is the acronym LARS. Left Add, Right Subtract. This tactic works regardless of being east or west of an agonic line.
LARS works for grid (map) to magnetic (compass).
Mag to grid get rig
Grid to mag add
A very clear explanation at a nice pace! :-)
Very informative. I’ve never understood or used Grid North before. Here’s a useful nemonic I learned in my early days of gaining my PPL nearly forty years ago. It even helped me in my CPL and ATPL studies later on! Going from True North to Magnetic North. Remember this: Variation West, Compass is Best. Variation East, Compass is Least! Variation W Compass Best, so Add the Variation to T North to get M North. Variation E Compass Least, so Subtract the Variation from T North to get M North. Just Reverse it if going from Magnetic North to True North! This is advice for general public reference: A Compass Heading is always given as 3 Figures eg. 000 Degrees (M) or (T) And the True or Magnetic Notation always comes After the Heading. This is an Aviation Example in the Northern Hemisphere! We don’t use Grid North in Aviation!!
Thank you so much Sir. That was an excelt explanation. God Bless you.
Best explanation so far about subject :) Thank you so much Greg. All this was so confusing for me andnow it is cleared :)
Best regards
It's nice to hear this from the perspective of one in Australia. Thank you . . . I think. Time playing with maps and in the field, while using the mnemonics, may assist.
Thanks for this. Very helpful!
Thank you Sir, for your explanations on a confusing subject. Great job on your video too.
Oscar
Very well done
Thx for the help
Thanks best tutorial
thank you, very helpful
In the Army many years ago our mnemomic was "Machine Gun Ammo" for Mag to Grid/Add" and "Grandma Sucks" for Grid to Mag/Subtract
We used the same in the Comandos. (Grandma Sucks).. Great video by the way.
My Great Ass and Grand Ma Sucks
Thanks for explanation
Nice video, but where is Grid North ? In UTM Zone 31, is it always in the center of the UTM Zone ? Or in the First Easting Line in contact with UTM Zone 31?
Left Add Right Subtract (LARS) is a pretty good rule. Doesn't matter if you're going from map to compass or compass to map, the direction of the shift dictates whether you add (going left) or subtract (going right).
SSG. U.S. Army (Medically Retired) Infantry / Sniper / SOF Intel (SOT-A), multiple tours
Great, THANKS
I’m confused why the 245 degree point was added when converting to grid (which made sense), yet the 145 degree point was subtracted when converting to magnetic? The bottom two quadrants aren’t making sense to me. If easterly (upper right quadrant) m-g is add, and the bottom left m-g is also add, wouldn’t the bottom right quadrant g-m be add and m-g be subtract, like The top left quadrant? I’d appreciate anyone clearing this up. Thank you!
Nice video, thanks a lot.
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I just have a question, as I'm doing my ATPL, is there any difference in the basic understanding of Grid and adding or subtracting between the North and South hemi?
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Just want to make sure I won't be adding more confusion to what I've already got about Polar nav and grid mappings
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Thanks a lot and once again, thanks for your time and effort
BMWCBR Hi BMW. I'm so sorry for the delay in responding. I've been overseas and out of contact for a lengthy period. The answer to your question is no, the rules about converting between Grid/True/Magnetic apply the same in both hemispheres. You just need to be sure you know whether you are dealing with westerly variation or easterly variation. Good luck with the ATPL
aus navigation No worries, and thanks a lot for your feedback ;)
Очень подробно , географический север мы используем вообще где-нибудь ?
I still don't understand grid north.
Are the sides of map are pointing to the north?
If that is the true, that what is the grid north.
Hey Fire. Yes the sides of the map (and the easting lines) are aligned with North / South, but not True North (which is 90°N). The grid system is drawn up differently to the Latitude / Longitude system and so "North" on the grid system (Grid North) is different to "North" on the Lat / Long system (True North). Unless you are in the high latitudes the difference is usually very small and is normally disregarded.
Great video and thanks for the detailed explanation. However, I am having some trouble figuring out the declination according to my basic perception of mathematics. My trouble starts after 10:24 after finding the easterly declination as of 2014 at 10.8 degrees. According to the declination diagram shown, when grid north is 0 degrees then magnetic north is 10.8. correct? therefore according to basic maths if i take a reading from that map of 1 degree grid north, my basic logic says that the magnetic north is now 11.8. to further try and make my point clear.. if i take a grid north reading of 10.8, according to my mathematical knowledge the mag. north is now 21.6. But! according to this video and several others ( I am not trying to say you are wrong as i know this is the proper way of teaching it, i am just trying to have it make sense to me) when i change from grid to mag (at an easterly variation) we have to get rid (subtract).. therefore magnetic north becomes 0. how is it possible that the grid north increased to the east from 0 to 10.8 but the magnetic north moved westerly from 10.8 to 0. that is my difficulty in understanding. I hope you can answer my question as I have had no success in having this explained to me properly but you look confident and knowledgeable in the subject. Thanks and best regards.
Thanks Michael. The wording of your question suggests a slight confusion. "when grid north is 0 degrees then magnetic north is 10.8. correct?"
Magnetic North is 0°M. Grid North is 0°G, in this example the two are 10.8° apart (which is the difference caused by the declination)
Magnetic North is 0°M which is 10.8°G by using MGA magnetic to grid add 0 + 10.8 = 10.8°G
If you want to convert Grid North 0°G to magnetic then you need to subtract the declination 0-10.8 = 349.2°M So in this example Grid North on your map would be achieved by following a heading of 349.2° on your compass.
Does that help at all?
***** Thanks for the comments Claud. Yes declination and converting True to Magnetic and Magnetic to True is a concept which is easily confused. If you read a compass which is pointing to magnetic North and you want to apply it to your chart in Easterly variation, you add the variation, to give you the True value. If you look at the north point diagram or variation diagram and you look at the line pointing to Magnetic North, you'll see that it is to the right of the True North / Grid North lines. The True North line is 0 degrees True, so by having magnetic north to the right of it, magnetic north is sitting in a position which is positive from True north. So the True heading of magnetic north is the value of True north PLUS the variation 10.8 degrees, giving a heading of 010.8 degrees True.
Much easier to just to remember MGA - Magnetic to Grid Add for easterly variation
***** thanks claudius at least i know im not alone hehe.. i realise that your (aus nav..) method is correct but i couldn't understand it at all for the last five years. what helped me was the tip you gave about both of them being zero. the trick is to imagine them in 3D instead of 2D as the diagram implies. thanks and happy holidays to all.
sektakavesi if you need any help claudius just say so and im willing to try and explain
If I orient the map using the compass do I need to consider declination or is it already factored in on the map?
There's normaly a table for true north on the map that you factor into your final result.
I was just reading a couple of written articles on what makes a good compass, as I'm in the market for one and want to make a wise purchase. I read two separate articles on two separate websites, and both said something regarding declination that I thought, based on the information in your video, was incorrect. The article's authors are supposed to be navigational experts, so perhaps it's me that's misinterpreted declination. I just wanted to copy these two quotes so I can ask you whether they are correct.
Quote from first article:
"A declination scale helps you make the declination adjustments for different areas so that the compass points to the true north instead of the magnetic north while the rotating bezel allows you to easily measure azimuth."
Quote from second article:
"“Declination” is the difference in degrees between true north and magnetic north."
So, I thought that declination was the difference between GRID north and magnetic north, not TRUE north and magnetic north. Both these experts are saying declination is the difference between TRUE north and magnetic north.
I believe for all intent and purposes they are the same. If you are finding a location on a trail, 1/7 of a degree won’t matter for 2 reasons. (The difference between true and grid north on this map is 1/7 of a degree.) If you could work out the trigonometry on that small of an error, it would be so small that you would still be able to see the car or pond that you’re looking for. Secondly, most compasses measure to 5 degrees and if you “cheat” by using the fine lines of mils scales that can overlap the degree scale you can get to 1 degree maybe. The error isn’t correctable or detectable with a compass and protractor. If you were trying to put a cruise missile in a certain window it might matter, but then again you probably won’t be using a compass to figure out targets. The difference is so small that many map makers don’t bother with grid north. You see it on military maps probably because the accuracy of an artillery strike is critical. I’ve seen maps with a degree or so of difference, but again most compasses don’t measure to 1 degree. There are videos that show how to use and correct for larger differences between true and grid north that can help.
@@Sodbusterrod True North is NOT the same as Grid North, and in the southern hemisphere, they are quite different. There are so many videos on TH-cam that pretend to teach navigation, but which repeatedly make the same mistake of saying Grid North (on the map) is the same as (points to) True North, which simply is quite wrong. The grid lines on a map are a parallel array. By definition, they can't possibly all point to the single point TN! They would have to be curved, as the longitude lines are, which DO all point to TN. The simple diagram in THIS video showing three "Norths" is quite correct. In New Zealand where I live, the declination for GN - MN is 21 degrees. TN to MN is 24 degrees. If I set off from here in search of Santa following Grid North, I will be a VERY long way off when I get there!
Oh, and instead of trying to remember adding or subtracting declination, just get a compass that lets you set the declination for the area you are in. Then forget all about adding/subtracting. It works for both map to compass and vice versa.
@@chriswood6984 "True North is NOT the same as Grid North" ... should be stamped in CAPS on every map. 👍
I like the military mnemonic: [M]ajor to [G]eneral is a promotion thus [M]agnetic to [G]rid add. [G]eneral to [M]ajor is a demotion, so [G]rid to [M]agnetic subtract.
Whats the difference between true N and Grid N?
Nice explanation MaGA GeMS for East
LARS works better for ether western or easterly GM ANGLE
10.7* east of grid north x 12
My employment of the data discussed herein will be 'on the trail' with standard compass. The directional needle of that compass will indicate Mag. North (MN) at all times. Any map I may be carrying will have a grid system that is NOT referenced directly to MN. The markings and dials of the compass will function as the 'Rosetta Stone' between these two disparate Nav Aids. Your presentation does not link the two in any useful, practical, field-applicable way. You have omitted the 'how-to' of the 'Rosetta' function of the compass. I concede with reasonable surety the compass needle points to MN and the map was drawn using accurate data. How these two objects arrived at this available form is of no value to me 'on the trail'. My need is to ascertain the present time, so to speak. Your presentation tells me how to build a watch. As such it does not fill my needs. The depth an quality of your presentation are moot.
The compass is right the maps are incorrect.
1892 Gleason Map is true.
Declination & Variation is the allowance calculated to hide the flat earth.
Bulls4it baffles brains & logic.
They say metal from ships a planes alters the compass magnetic pull.
What about a fiberglass boat or glider???
Allowance still made in both.
The real shape of Australia is on the Gleason, land mass is altered to fit the global deception of a spherical (oblate) globe earth.
The magnetic deviation is enormous around Australia.
Modern navigation when flying or sailing auto corrects using electric compass equipment & human pilots/captains have lost critical thinking skills to question anything they have been taught.