How to orient a map to True North
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- Опубліковано 4 вер 2017
- theprepared.com/guides/learn-... Part of a free one page guide on survival navigation basics.
Survival expert Jessie Krebs shows how to use a compass to orient a map to True North, not Magnetic North.
EXCELLENT! There are a lot of videos on YT of people teaching improper orientation of a map (i.e. compass needle aligned with grid north). Thank you for presenting the correct method.
To be exact, you pointed to the GM angle on your map which is the difference between grid north and magnetic north; true north does not come into the conversation.
Need more compass videos please. Thanks!
Good lecture & simple . Thanks 👍👍👍👍👍
Nice and simple..
Hello I am on east coast.. I have some older topo maps that are 30+ years old that I would LIKE to still use. For example they indicate around 6-7 degree (depending on map) declination. I looked online and today its about 10.4. Can I set my compass to the 10.4 offset and still use the older map? orienting the map to true north but with today's declination? Also, when I travel my route I assume leave the declination offset in place on my compass. Thank you...
Once oriented as explained in your video, can you then take a bearing off the map and proceed to follow that bearing in the real world without the need to adjust for magnetic declination any further?
Never knew about the neat line. Spent alot of time studying about it. Cool.
The Prepared - intrigued about the neatline comments. I understand a neatline is the outermost perimeter separating the map from the white margin. But are you indicating you cannot use the inner lines for this exercise? I would think that any of the lines of longitude would suffice to orient the map especially when considering the margins of error inherent in the exercise but would like to hear more please. I am sure it probably has to do with the representation of a spherical earth on a flat surface and how lines of longitude are not technically parallel like lines of latitude? Nice video!
@@condor5635 My apologies for the delay in getting back with you! Any line of longitude will work, however both sides of the map can't be a line of longitude if the map is truly rectangular since as you noted the world isn't!
Often these days there is a UTM grid overlay on maps which I love (I'm a fan of UTM grid over lat/long and other coordinate systems I've heard of). However many folks incorrectly think that the generally north/south running lines of the grid are lines of longitude. They often are pretty close, but can occasionally be up to several degrees off of true north (lines of longitude), especially on maps closer to the poles. Most maps I've seen lately only have + signs to indicate lat/long on the map, not lines. So to use a line of longitude I would have to have a compass long enough to connect two of the + signs or draw a line between them on the map myself.
Basic message: be sure you're using a line of longitude to orient a map (which the neat line should be. Check that the degrees, minutes, and seconds of longitude at the bottom and top of the map along one edge are the same to be sure you're using the neat line. I occasionally find it to be the right instead of the left side!)
Thank you for your interest, question, and for watching!
@@ThePrepared I was looking at this video again. I noticed there are 3 points on the declination area. Grid North, true North and magnetic North. Do you think that the compass was set up just short of being able to properly orient the map? Still a good video though.
@@robmart8255, great question! For ease/simplicity, I ignored grid north for the video, and when we look up magnetic variation online it gives us the difference between lines of longitude (true north) and current magnetic north. Grid north is a good thing to look at because it can tell us if the grid lines on that particular map are lined up exactly with lines of longitude or not, but otherwise is not to be trusted for orienting. As long as I'm using the neat line/a line of longitude and the current magnetic variation for my location I'll be good to go!
So If I understood, the map is always oriented towards grid. My declination is positive 13°east. I have set my compass to 347° but I'm wondering why it's not set to 13°? I think what confuses me is Left Add Right Subtract(LARS/Magnetic to Grid Add Grid to Magnetic Subtract) can someone help me out thanks!
감사합니다 😁
Am i crazy, does orienting a map affect the conversion from magnetic bearings to a plottable map grid coordinate in anyway? Orienting a map is just convenient to make sure when you look up from the map you are looking at the right land features, right? It doesnt actually affect any math??
I'm new here. Just arrived.
It really enrages me when people don't, can't or won't orientate a map to north. It drives me nuts.
Same thing happens to me when people put papers on my desk chair at work.
@@wmluna381 nice
Hey Jesse, what if my map has a difference of 19.5 degrees west? Would I add or subtract that? Cheers
@@ThePrepared Awesome thanks for the tip. One more question if you don’t mind. So to clarify, when you’re getting your bearing after you plotted your two points. You always want to orientate the map facing North?
@@ThePrepared Awesome thanks
is there difference between grid N and true N and do we need to account for that? Is true N same as Grid N? Magnetic is clear. Those 2 unclear. I will simply do my own research but your perspective would be much appreciated too. Thank you.
Yep, there is a difference on many maps between grid north and true north, since the UTM grid is rectangular and the world is round! I generally ignore grid north for anything having to do with orienting the map. It's just not meant to be used for that! Unfortunately the lines of longitude are usually NOT drawn on a map though-just the little tic marks (+ signs) to indicate where they run, hence why I like to figure out which side is the neat line and use that for ease and accuracy.
@@jessiekrebs5764 I appreciate your time. I guess topography is a good skill to have but in this day and age we can do well with technology especially only for a day hike or something like that even in remote areas. I love maps thought.)) Navigate using my instincts =DD
@@coniferousforests8030 Sure we have some awesome tech now that a lot of folks use on day hikes and such. The problem comes when batteries die, or the tech breaks/is lost. Many people end up in trouble because they depended on a piece of equipment and didn't learn even the most basic of skills or practice basic awareness. Beyond safety, I think learning wilderness skills is fun and empowering too though. It encourages people to see their surroundings in a new way and understand it on a deeper level. Helps sharpen those instincts! Happy hiking!
Grid North is is simply showing the direction of the Grid North Pole (this is not actually a physical location, per-say - it is more along the lines of the direction that the Grid North Lines would point to from a flat map - that has been created from a round world globe) these lines will effectively point to a slightly different location, as opposed to True North. Therefore Grid North normally has a slightly different angle in relation to Magnetic North. These Grid North Lines run North / South on the map and are sometimes called the Easting Lines, because they are numbered from West to East on the map. These Grid North lines are created onto the map when the map is made and when the map is properly orientated to the ground (taking the Magnetic Declination into account) then these Grid North Lines normally point to a slightly different place compared to True North. I believe that when using a map and compass. You will get better accuracy using Grid North when also working with a compass.
True North is simply showing the direction to the North Pole in relation to Magnetic North. This is not as accurate as the Grid North Lines. But is you were wanting to travel to the North Pole, then using True North would be a must. However it is more accurate to use the Grid Lines on your map as these are specific to your map, for your location on the earth. Therefore I would suggest using Grid North and taking the difference in degrees or mils into account when adding or subtracting your magnetic declination on your compass. because Grid North is the direction of all vertical grid lines on a topographical map. And due to the distortion of transferring a spherical surface to a flat map there is an error between Grid North and True North. Even if the difference is only 4°, this can make a huge difference on the ground when traveling over long distances. And is best accounted for in my opinion.
Sorry for the long explanation. This particular subject is difficult to explain in words.
How would you add something like 10 west? Like, how would you put 370 on a compass?
Really late response I know, but think of "360" more like a "zero" as in you are zero degrees off from your target of the magnetic north pole. So "370"is actually now just 10!
Why would you use true north as opposed to magnetic north? We always used magnetic to grid with our declination as well.
@@ThePrepared thank you
@@Asymmetrical.athlete_ Maps are actually orientated with Grid North, but normally also display True North as a reference point that you can also use. Grid North is actually more accurate because it is specific to your map and location on earth.
@@KiwiBushcraftAndSurvival hence why I said we use the declination
hmm.. unless I am much mistaken the sequence is as follows: reconcile for the difference between poles (True N and Magn N) , then align the compass with the side line/edge of the map, rotate until red in the shed. A little bit mind-boggling as each tutorial teaches it its own way =SS For instance Some people adjust declination, then place compass on the map aligning with the meridian (or the side line/edge of the map), then align manually the N indicator (on the bezel dial/ring) with the index pointer (which is where the direction of the travel arrow begins) and then rotate the map. I.e. here ua-cam.com/video/a2aGiUl1u4c/v-deo.html thank you.
Where did you get that Map?
@@ThePrepared thanks for being so helpful!
So the other lines on the map are the grid north lines?
Yes Andrew. The UTM grid is a great coordinate system that is used by the military and many organizations instead of the Latitude/Longitude coordinate system. There have been hundreds of different coordinate systems invented over the centuries, but these two are of the most popular and most commonly used. The problem when orienting the map is that the grid lines of UTM are usually shown on maps, while the Lat/Long lines are not. This is a problem because generally UTM lines do not/cannot run parallel to lines of Longitude (which always run directly to the north pole/true north). So many people mistakenly think that the generally N/S running lines they see on the map are lines of Longitude and are what they are supposed to use to orient the map, when this is not the case. The UTM grid lines are not there for that purpose and may be several degrees off of true north. Hence why I recommend looking at the right and left sides of the map closely to determine which is a true line of Longitude (the neat line) and using that for orienting.
@@jessiekrebs5764 Gotcha, thanks for the reply. But why aren't the grid lines helpful? Wouldn't you just use the declination diagram to find the declination from Grid North instead of True North? That is how it's done in the military.
@@andrewhagstrom7842, I'm surprised the military is using the grid lines now, we taught using the neat line (or any line of longitude) when I was in, but that was 30 years ago! I'm still not a fan of using the grid lines, one because most civilian topo maps I've seen in outdoor stores now don't use a declination diagram but a compass rose which usually doesn't show grid north at all. Another reason is that occasionally I've come across a map that has the seam where two UTM grid sections come together and due to the nature of the grid being on a round planet the overlap creates two different grids that can point in slightly different directions. Another reason is that when I look online for the current declination of a given area it will give that in true north, not grid north, so to be accurate again, using a true line of longitude is best. Overall for beginners especially, and ease and accuracy all around I'm in favor of using the neat line or line of longitude over grid lines for orienting a map.
@@jessiekrebs5764 Ok, that makes sense. Interesting. Well, the Army has been using Grid North as their basis for orientation for a long time. In this training video from the 1960s, a soldier orients his map using the declination between grid north and magnetic north (known as the "G-M angle"): ua-cam.com/video/V-u9uPWOVVg/v-deo.html. Skip to the 10:00 minute mark in the video. Also, we used the declination between grid north and magnetic to do land navigation when I went to Marine Officer Candidate School last summer.
Thanks, now why couldn't all the other talking heads on here explain it concise like you did instead of going about it like a calculus class?
Strange compass, shed?
Hi Jesyca, orienteering compasses like the one shown here are the most popular civilian compasses on the market by far, though not my preferred type. They use a concept generally referred to as "putting red Fred in the shed". To use them the operator must get the desired heading over the stationary index line and then turn the compass until the red part of the floating (magnetic north seeking) arrow is framed by the outline of an arrow on the base-plate below it. Once those two are lined up the operator knows that the direction of travel arrow is now pointing in the desired direction.
Who is fred? What? What shed? so confused. A little more time on the subject would be helpful.