PDA

View Full Version : Is there a "right" kind of compass?



Toe Cozy
07-06-2006, 07:39 AM
I don't own a compass. (your collective hiking safety faux pas gasp is audible from here ;) ). I have used a compass rose, parallel ruler and a compass (the tool with two sharp points) to plot a sailing course on a nautical chart but I haven't ever used a compass in the woods. I'd like to experiment with using a compass but I have no idea what is the "right" kind of compass to get.

Any recommendations, suggestions, experiences to share in learning about compass use would be great.

Thanks.

Tom Rankin
07-06-2006, 08:07 AM
I don't own a compass. (your collective hiking safety faux pas gasp is audible from here ;) ). I have used a compass rose, parallel ruler and a compass (the tool with two sharp points) to plot a sailing course on a nautical chart but I haven't ever used a compass in the woods. I'd like to experiment with using a compass but I have no idea what is the "right" kind of compass to get.

Any recommendations, suggestions, experiences to share in learning about compass use would be great.

Thanks.You almost never need a compass, right gang? And you've made it this far w/o one, so why get one now!? :eek: :D

Seriously, you can get a light-weight compass at almost any outfitter. I have one that attaches to a clip inside my pack, so it's really hard to lose. I actually have 2 compasses, the 2nd one is on a multi-purpose tool.

Bushwhackers usually bring more than one.

There are courses you can take to learn navigational skills. I'm sure someone will add details.

cbcbd
07-06-2006, 08:27 AM
You almost never need a compass, right gang? And you've made it this far w/o one, so why get one now!? :eek: :D
If you only stick to marked trails and Summer hiking then I'd agree that it's not completely necessary unless you have a knack for losing the trail.

But... it's nice to have a compass since you'll probably use it for fun or for real in the future anyway.

I personally prefer and would recommend getting one that has adjustable declination - you won't have to add or subtract everytime you read the compass and that just makes life simpler.

Neil
07-06-2006, 08:32 AM
I'd like to experiment with using a compass but I have no idea what is the "right" kind of compass to get.

Start with a cheap one, but with a rotating ring and a fluid dampened needle. All the hip bushwhackers wear them on a string around their neck. :)

Something like THIS (http://www.mec.ca/Products/product_detail.jsp?PRODUCT%3C%3Eprd_id=84552444177 1987&FOLDER%3C%3Efolder_id=2534374302696143&bmUID=1152192663314)

10 bucks should do it.

nartreb
07-06-2006, 08:52 AM
The main point to look for is that it should point north. Seriously, there's not much to know about compasses for basic "did I take the wrong turn in the fog?" use. A larger-diameter compass tends to allow more precise readings, but that may be moot if your trail wiggles a bunch and you have no landmarks to sight on. Some have a bezel you can adjust for local declination (about fifteen degrees in NH, IIRC), or to "dial in" a desired heading.
I've got a flat, clear plastic model that glows in the dark and includes a ruler and a magnifying glass for map-reading; I think I paid ten bucks for it. [Edit: it's quite similar to the one Neil suggested.] I keep it in a front pocket (and leashed to my belt) so I can check it frequently (at least every half hour if I'm on an unfamiliar trail or visibility is poor) - the idea is to know my position and direction *before* I get lost.

Jay H
07-06-2006, 09:04 AM
There are different kinds of compasses too.

I use a
Brunton 8096 (http://www.amazon.com/gp/product/B000059HMJ/002-2658622-8667246?v=glance&n=3375251)

Compass which has a basic (not that useful) UTM grid on it. Some GPS SA stuff which is useless now that SA is off, but what I do find somewhat useful is the extended ruler on the edge, you can extend it out so that you have a long straight-edge. When plotting bearings on a map with the magnetic north gridlines marked on it, the extention to the straight edge is useful. Many maps don't come with the magnetic north grid on it but the NYNJTC ones for the catskills do or you can make them yourself.

Other than that, a basic lay-flat compass is useful.

A basic lensatic compass (http://www.amazon.com/gp/product/B000093ILS/002-2658622-8667246?v=glance&n=3375251) is better at taking visual bearings to landmarks (useing the mirror'ed lenscap and sight) but is not needed for the most part, you can obviously still take bearings with a basic compass, just not as accurate over longer distances as a lensatic one.

Jay

Kevin Rooney
07-06-2006, 09:13 AM
I personally prefer and would recommend getting one that has adjustable declination - you won't have to add or subtract everytime you read the compass and that just makes life simpler.On adjusting for declination - while that makes life easier in terms of the math - there is one caveat: it's a good idea to make/tape some note to the compass if the declination has been altered from its factory setting. Otherwise, if later you pick it up, or someone else does, they make correct for declination again, and now you're WAY off! It can be difficult to determine whether a compass has been 'corrected' for declination simply by looking at it. I believe Freedom of the Hills recommends changing the declination on adjustable compasses, but I strongly disagree, both for the reason I mentioned above, and especially if you travel from East to West coasts, where the declination is added rather than substracted. My own preference is to leave the compass alone (leave at factory setting) and that way I have confidence in it. After all, the declination is always in the legend of a map. But, you do have to remember to either add or subtract, depending upon which side of the Mississippi (roughly) you're on.

TCD
07-06-2006, 09:38 AM
I agree with some of the above. I'd start with a cheapie, just to get the idea. Take a basic map and compass course from any local hiking group, or go with some of the intrepid and skilled bushwackers here. Like most equipment, if you start with something cheap and use it for a while, you'll quickly learn what features you want in a better unit.

If you decide to do a lot of off trail travel, and you want to be more accurate, then pick up a better compass. Features that help are larger dials, adjustable declination, sighting mirrors, etc. I have a Silva Ranger that I got at a discount for about 30 bucks, and it's all I need.

(Kevin, I've always had good luck with adjusting the declination. But it's easy to see the adjustment on my compass, so maybe that's why. I like making the adjustment, because I never have to think about it unless I go to a different area. And the tiny screwdriver is right on the compass lanyard, so it's always easy to change it.)

TCD

Rick
07-06-2006, 09:39 AM
Toe Cozy,
Congratulations on deciding to get a compass.
But, by no means is using a compass a "walk in the park" (sorry, I just couldn;t help it).

It does take work, knowledge and practice to really operate one, (I'm not talking about simply finding North here...)

I would strongly suggest you start out with a simple one as Neil refers to and if as you learn the basics, you decide you'd like the mechanics of adjustable declination and sighting mirrors, purchase a nicer orienteering compass which has these and more features.

I would also try to hook up with an orienteering group or if you belong to the AMC or ADK, see if any experienced users are offering a workshop.

To some folks, using a map & compass comes easy - To others it can be sheer confusion. Not that anyone on this board would ever do such a thing :eek: but finding you are not where you thought you were is never the best time to pull one out of your pack and learn how to use it.

I also like Kevin's point. I keep declinations for various favorite areas that I visit, taped to the back of my compass so I can quickly look them up and adjust. (Well, I don't really have to look them up anymore, since they are easy to memorize, but none the less, they are still taped there...)

Rick
07-06-2006, 09:40 AM
If it sounds like I am repeating TCD - I think we were posting at the same time....... Great minds....!!!!

DougPaul
07-06-2006, 10:48 AM
If you have nautical navigational experience, then using a compass hiking should be pretty easy. Except, no nav table, no parallel ruler, and no dividers...

The simplest "serious" compass is a basic protracter compass, such as Neil suggested or
http://www.rei.com/online/store/ProductDisplay?storeId=8000&catalogId=40000008000&productId=48028654&parent_category_rn=4500598&vcat=REI_SSHP_CAMPING_TOC
or
http://www.rei.com/online/store/ProductDisplay?storeId=8000&catalogId=40000008000&productId=47935359&parent_category_rn=4500598&vcat=REI_SSHP_CAMPING_TOC.

Useful features are mirrors for more accurate sightings, luminous points for use in the dark, and declination adjustment (useful IMO--in any case you can just set it to zero if you want to do the magnetic to true conversion in your head). Skiers, those wishing to avoid avalanches, and geologists may also apreciate a clinometer (measures slope angles). The Silva Ranger is a classic which includes all of these features (I have one and have used it both on land and sea) http://www.rei.com/online/store/ProductDisplay?storeId=8000&catalogId=40000008000&productId=737&parent_category_rn=4500598&vcat=REI_SSHP_CAMPING_TOC

There are also very simple compasses eg http://www.rei.com/online/store/Search?storeId=8000&crumb=GPS+and+Compasses%5E%26title%3DGPS%2Band%2BC ompasses%26link%3D1%26cat%3D4500059%26query%3D*%7E Compasses%5E%26cat%3D4500598&title=GPS+and+Compasses&link=1&cat=4500598&query=*&text=1&vcat=REI_SSHP_CAMPING_TOC:N which make good backups. I also have a very similar compass on a wrist strap which is good enough for holding a general heading while bushwacking.

Doug

onestep
07-06-2006, 11:03 AM
<snip> I'd start with a cheapie, just to get the idea. <snip> if you start with something cheap and use it for a while, you'll quickly learn what features you want in a better unit.
TCD
I learned map & compass during a timber cruising course I took. We walked straight parallel lines criss-crossing a wood lot while stopping at predetermined distances to plot tree growth. For such accuracy we used expensive compasses with all the bells and whistles mentioned through out this thread.

Now that my passion is bushwhacking 3K peaks I've had to "unlearn" much of what I was taught. Today my compass points me in the general direction I want to travel and then I let the terrain guide me. No more marching in straight lines with utmost precision.

My compass of choice today? A $10.00 cheapie as described by Neil. (and yes, it hangs on a string from around my neck) :D :D

Onestep

Toe Cozy
07-06-2006, 11:21 AM
Thanks everyone. This is just the kind of stuff I was looking for. The GMC (Green Mountain Club) offers compass skills courses. I should take advantage of that.


Originally Posted by Rick
Not that anyone on this board would ever do such a thing but finding you are not where you thought you were is never the best time to pull one out of your pack and learn how to use it.

This is exactly why I'd like to play around with the compass in a normal situation and be comfortable with it. I'm becoming interested in exploring places off trail more. Tired of sticking to the path. So far I've avoided this because of a fear of getting lost and panicked. Knowing how to use a compass will make me more comfortable with the idea of going off trail. Waiting for necessity is not the best way to learn how to use my gear effectively! Well, I also can't wait to wear one around my neck. I think it's gonna be a hot fashion trend!

DougPaul
07-06-2006, 11:23 AM
Now that my passion is bushwhacking 3K peaks I've had to "unlearn" much of what I was taught. Today my compass points me in the general direction I want to travel and then I let the terrain guide me. No more marching in straight lines with utmost precision.
This is sufficient in many (most?) cases.

However, I have used the precision sighting and plotting on a map features several times. In one case, the trail had been moved (not reflected on the map), it was clear that it wasn't following the map, and I wanted to see where it was leading us. In another case, I was on a heavily treed ridge and I wanted to locate myself with a backbearing off a visible peak. Would I have been able to do a sufficient job with a simple protracter compass? Perhaps, but I appreciated the extra accuaracy in these situations.

Doug

Neil
07-06-2006, 11:27 AM
I have one last suggestion (http://www.atoygarden.com/images/products/AnimalCompass280.jpg)for a starter compass.

DougPaul
07-06-2006, 11:29 AM
Well, I also can't wait to wear one around my neck. I think it's gonna be a hot fashion trend!
IMO, wearing a compass around one's neck is a minor nuisance. It swings around, bangs into one's chest, and catches in the foliage when bushwacking. Much nicer if you can put the cord around your neck and the compass in a shirt pocket. (But they don't tend to put pockets on hiking tee shirts... :( ) You can also just stick it inside your shirt or between layers to stop the swinging.

Doug

carole
07-06-2006, 12:43 PM
Check the size of the numbers/letters in a dark corner of the store. Some of them are such a fine print they can be difficult to read when out there somewhere.

Jay H
07-06-2006, 12:57 PM
I usually stuff the compass in my shirt when bushwacking and not needing the compass at the moment.

My brunton's view is magnefied and also instead of lining up the rose with the north, it uses two circles which I find easier to do in low light.

Jay

Neil
07-06-2006, 12:58 PM
IMO, wearing a compass around one's neck is a minor nuisance. It swings around, bangs into one's chest, and catches in the foliage when bushwacking. Much nicer if you can put the cord around your neck and the compass in a shirt pocket. (But they don't tend to put pockets on hiking tee shirts... :( ) You can also just stick it inside your shirt or between layers to stop the swinging.

Doug
I've never had that problem. I can't remember if I let it dangle free or if I put it under my sternum strap. I think the former. I do remember putting it inside my shirt once and it came out all gooey with sweat.

4000'er
07-06-2006, 01:16 PM
The Suunto A-10 Compass (http://www.rei.com/online/store/ProductDisplay?productId=47935359&storeId=8000&catalogId=40000008000&langId=-1&addon=738795-727086&ext_cat=REI_RELATED_ITEMS_PRODUCT_PAGE&vcat=REI_SSHP_CAMPING_TOC) is a good starter compass as well.

Also check out (As from your local library) Be Expert with Map and Compass (http://www.amazon.com/gp/product/0020292651/104-5135486-4403913?v=glance&n=283155) by Björn Kjellström.
That will get you going.

sardog1
07-06-2006, 01:20 PM
This is a question that I deal with on an almost weekly basis. It is also one on which I have very strong opinions:

1. Neil and Jay H are right on the money. Either of the two compasses they have recommended would work very well for hiking. (EDIT: As would the other compasses of the same type recommended by others on this thread. ) They are generically known as "orienteering" or "map" or "baseplate" or "Silva-type" compasses. You don't need one with a sighting mirror (http://us.st11.yimg.com/us.st.yimg.com/I/thecompassstore_1904_7092932) unless you plan to spend lots of time above treeline, or on the water, or out West. In the Northeastern woods, you won't see far enough to make a significant improvement in accuracy by using a sighting mirror.

2. Having the capacity to set a correction for declination is extremely useful. I prefer a small set screw in the bezel ring for this, as in the Silva Ranger. Other types of corrections are either (a) too easy to mess up without noticing (e.g., a rotating capsule/vial set in the bezel (http://www.brunton.com/images/catalog/9020G.jpg) ) or (b) too easy to forget to use (e.g., a declination scale on the base plate (http://www.brunton.com/images/catalog/7DNL.jpg) .)

If you use a compass with a declination correction feature and you happen to travel from NH to VT (or NH to ME) without making the small adjustment required in that instance, you ain't gonna be too far off the mark. The difference in declination between those pairs of states is only a couple of degrees, andf you'll often be making errors that large anyway.

Yes, if you wander from NH to WA or CA, and you don't make the large adjustment required in that instance, you'll be horribly confused and probably die of starvation in the woods. But you wouldn't forget to change your watch to account for the time zone shift, would you? Then just remember to set the declination change when you change your watch and you'll be fine. Likewise, if you ever loan your compass to someone else, remember to check the declination before you use it again.

3. Other types of compasses, especially the "lensatic (http://us.st11.yimg.com/us.st.yimg.com/I/thecompassstore_1904_686952)", are much less useful. The principal virtue of the lensatic compass is that it is handy for calling in mortar fire, which is where most of its adherents learned to use it (or they inherited an affection for it from family members in the military.) (Yes, I know it's also handy for timber cruising and the like.)

4. Read the fine print in the instruction pamphlet that comes with a new compass very carefully. Then take a topographic map and compass to an area you know well, e.g., your neighborhood or a favorite dayhike. Practice everything that the pamphlet tells you to do. Do it again and again. Then do it some more.

And find some orienteering events to sharpen your map and compass skills -- you'll be amazed what it will do for your navigation abilities. Orienteering compels you to make route choices constantly and you get instant feedback, both positive and negative. (Oooh, why did I ever think it was better to wade through that swamp? :mad: )

EDIT: Be Expert With Map and Compass is also my first recommendation for a text. Read and use the book -- your traveling companions will envy your navigational prowess.

Neil
07-06-2006, 01:57 PM
While we're on the topic of off-trail navigating I can't recommend highly enoughthis amazing article (http://www.adkhighpeaks.com/forums/nava.php) which was written by a VFTT forum member. I printed the article and read it carefully then read it again with a map and compass on the table. Then I went out and applied it all in the field. I used to think I was pretty good with M&C. NOW, I'm getting there thanks to this extremely well written and easy to read 20 pages.

As you'll quickly find out the compass is only a part of the overall equation. Map study/interpretation and terrain feature recognition are the other 2 sides of the triangle.

(If you can't access the link then you have to register on the forum.)

sardog1
07-06-2006, 02:08 PM
While we're on the topic of off-trail navigating I can't recommend highly enoughthis amazing article (http://www.adkhighpeaks.com/forums/nava.php) which was written by a VFTT forum member.

Very good point. This article contains hundreds of pearls of navigation wisdom. Think you're an expert? Everybody should read Repak's article and (re)discover some techniques you weren't using and should be using. (How can you go wrong following the advice of a guy who quotes Roald Amundsen?)

Pete_Hickey
07-06-2006, 02:17 PM
You Bushwhackers usually bring more than one.
Wouldn't that be a great bumper sticker....

"Bushwhackers have two"

sardog1
07-06-2006, 02:28 PM
Wouldn't that be a great bumper sticker....

"Bushwhackers have two"

Left both of mine in the truck once. Damn glad to have the etrex Vista electronic one along one night, on the only occasion I ever needed it, to avoid this:

"Uh, Shepherd 17, Base."

"Base."

"Uh, Base, I left both my compasses in my truck. Can you sound a loud horn so I can find my way out of the woods?"

(The rest of this scenario is drowned out in my imagination by the peals of laughter that follow over the radio from multiple sources . . . .)

Stan
07-06-2006, 03:02 PM
I have used a compass rose, parallel ruler and a compass (the tool with two sharp points) to plot a sailing course on a nautical chart but I haven't ever used a compass in the woods.
If you've done any dead reckoning at sea then it is easy to adapt to navigation on land. In fact, it can be easier with both feet on the ground and much stronger hints to reinforce your compass course.

If you have nautical navigation experience I'd be careful about taking the map and compass course. Although the principles are the same, there seem to be different techniques that can lead to confusion. However, if your nautical navigation skills are very rusty or if they're not fully developed, then most map and compass courses will get you on your way.

Any compass will do and a spare is highly recommended for off trail navigation. Though I never needed to take a fix based on bearings to identified landmarks or summits (triangulation), a compass with a folding hairline would be helpful in getting accurate bearings.

When I bushwhack I wear the compass around my neck and stow it in my shirt, vest or coat pocket to keep it easily accessible but out of the way.

Aside from bushwhacking, there are two other times that I use my compass. First, when I am on an unmarked or remote trail and sometimes at certain waypoints just to confirm my orientation. It's amazing how your sense of direction can sometimes deceive you when there are changes in daylight, terrain or even vegetation. It is an easy precaution to take and comfort with your orientation is preferably achieved before any emergency, accidnet or disorienting event occurs. Stay true to your compass ... I once concluded that I'd have hiked from northern Maine to Quebec a la "The Girl who Loved Tom Gordon" if I had relied solely on my instincts.

The other time is that I find it fun and a good way to practice to take bearings to other summits when I reach a peak, then plot it at home for comparison.

... and, you can use an analog watch as a a compass if the sun is shining. Point the hour hand to the sun and 12 will point true south and 6 true north.

DougPaul
07-06-2006, 03:48 PM
... and, you can use an analog watch as a a compass if the sun is shining. Point the hour hand to the sun and 12 will point true south and 6 true north.
Close but no cigar...

The above only works with a 24hr watch set on local standard time.

For a 12 hour watch:
1. The watch needs to be on standard time (when on daylight savings time, mentally move the hour hand to 1 hour earlier).
2. Bisect the angle (ie take the midline of the two) between the hour hand and 12 and point this new line at the sun.
3. 12 now points approximately south and 6 approximately north

This method is only approximate--one obvious source of error is location in the timezone (+-7.5 degrees) and there are other sources of error.

Doug

Neil
07-06-2006, 07:11 PM
Wouldn't that be a great bumper sticker....

"Bushwhackers have two"
What about:
"Bushwhackers take it in the eye"

sardog1
07-06-2006, 07:49 PM
One more thing on the subject of compass selection.

I admire Silva a lot for what they've done over the years to advance the cause of navigation and the sport of orienteering. But that electronic compass they brought out recently (one of which was given to me last year) is the Devil's spawn.

Folks, it might look like a duck at first glance. It might even seem to quack like a duck. But it sure as #$%@ isn't a real orienteering compass, and you'll notice it the first time you try to use it with a map. Stick with the analog versions and stay away from the digital when it comes to buying a hiking/orienteering compass.

Paradox
07-06-2006, 08:23 PM
One more thing on the subject of compass selection.

... that electronic compass they brought out recently (one of which was given to me last year) is the Devil's spawn..... Stick with the analog versions and stay away from the digital when it comes to buying a hiking/orienteering compass.

I concur. Most of the electronic "flux gate" type compasses must be held such that the plane defined by the compass rose is parallel to the horizon line. This is much easier to do on the water, than on land. A $20 non-electronic compass could save your butt from my snarky jokes :D (or worse:( ) in a snow storm or the fog. Plus, you don't have to worry about batteries.

I always carry my Brunton Eclipse compass though I have never had to use it to get out of a tenuous situation. I only seem to use it to identify a mountain peak here or there or just because I find it fun to use. I use a mapping GPS, which provides far more information and is much easier to use, but they cost far more and their is problems with batteries and reception.

thuja
07-06-2006, 09:46 PM
On adjusting for declination - while that makes life easier in terms of the math - there is one caveat: it's a good idea to make/tape some note to the compass if the declination has been altered from its factory setting. Otherwise, if later you pick it up, or someone else does, they make correct for declination again, and now you're WAY off! It can be difficult to determine whether a compass has been 'corrected' for declination simply by looking at it.

This is a point of view I have never encountered before. There is an easy way to tell roughly what the declination is set at by seeing where the fixed transparent arrow points to on the dial. It's as easy as looking down and seeing, "hm", this arrow points a little over 20 degrees to the right of the "N", I guess it's set okay for Washington where magnetic N is 's 21 degrees E of true N. I have used compasses in areas all the way from 25 degrees one way (in British Columbia) to 20 degrees the other way, in Maine. And resetting that declination has never been a problem. Once you figure it out it's a ton easier and more intuitive to use than this method of not adjusting that you propose.

sleeping bear
07-06-2006, 10:25 PM
Comparing a GPS to map and compass and saying that one is easier to use or provides more information is like saying coke is better than pepsi. GPS can be complicated to learn how to use and requires more time to use out in the woods., although M & C is hard until you get it. Once you get it, though, you get it. If you have a good map, are okay with the compass, and can read the environment, you will probably know the same or more than a GPS would tell you.

A couple of weeks ago on the Baldfaces, we got a little confused by the signs on NBF. We were going the correct way and had not missed any turns, we just though we were somewhere else. This became apparent over the course of a mile or so as the trail did not turn down the ridge as we expected it to. I pulled out my compass, oriented the map and was able to determine that we were still on the main ridge running N/S and had not in fact turned down the trail heading East. We probably could have figured it out with just the map, but the compass helped to be certain. So, it may come in handy from time to time, even in the summer on (poorly/confusingly) marked trails. :D

DougPaul
07-06-2006, 10:32 PM
On adjusting for declination - while that makes life easier in terms of the math - there is one caveat: it's a good idea to make/tape some note to the compass if the declination has been altered from its factory setting. Otherwise, if later you pick it up, or someone else does, they make correct for declination again, and now you're WAY off! It can be difficult to determine whether a compass has been 'corrected' for declination simply by looking at it.


This is a point of view I have never encountered before. There is an easy way to tell roughly what the declination is set at by seeing where the fixed transparent arrow points to on the dial. It's as easy as looking down and seeing, "hm", this arrow points a little over 20 degrees to the right of the "N", I guess it's set okay for Washington where magnetic N is 's 21 degrees E of true N. I have used compasses in areas all the way from 25 degrees one way (in British Columbia) to 20 degrees the other way, in Maine. And resetting that declination has never been a problem. Once you figure it out it's a ton easier and more intuitive to use than this method of not adjusting that you propose.

I agree with thuja on this one. The declination is easy to check and set. If one is in bad conditions and really needs to use the compass, it lessens the chance of an error. It just makes the process of transferring a heading between the map and the world simpler.

But ultimately one can use the automatic declination or not as one prefers.

FWIW, in contrast to land navigation, nautical and aeronautical navigation use magnetic headings. (Nautical charts come with a magnetically oriented compass rose--don't know about aeronautical charts.)

Doug

sardog1
07-06-2006, 10:48 PM
FWIW, in contrast to land navigation, nautical and aeronautical navigation use magnetic headings.

Well, now you've gone and done it. You just had to smoke me out on magnetic bearings, didn't you? ;) Here's a tip that I am loath to offer (see below), but it will simplify life for many of you.

Orienteers draw a series of parallel "north lines" on their maps, aimed at magnetic north and using as a guide the declination diagram found on any decent topo map. They space the lines at intervals convenient for the size of the map and the size of their compass baseplates. Then they never, ever worry about declination. They just use the lines to locate "North" on the map for compass purposes and off they go.

You can do the same thing to your maps in the comfort of your home before you go into the woods, if you don't mind marking them. (I do. Mind, that is.)

Why am I reluctant to pass on this tip? Mostly because I think you're better off in the long run understanding declination and how to compensate for it. But I might be in a very small minority on that point.

DougPaul
07-06-2006, 10:55 PM
Comparing a GPS to map and compass and saying that one is easier to use or provides more information is like saying coke is better than pepsi. GPS can be complicated to learn how to use and requires more time to use out in the woods., although M & C is hard until you get it. Once you get it, though, you get it. If you have a good map, are okay with the compass, and can read the environment, you will probably know the same or more than a GPS would tell you.
A GPS and a compass tell you different things which can be related to each other with a small amout of effort. A GPS directly gives you location, altitude, time, and direction and speed of movement (a 7-tuple: 3 dimensions of position, 3 dimensions of velocity, and 1 dimension of time). (A mapping GPS can also plot your location and track directly on a map for you.) A compass directly tells you only directions (bearings). A set of bearings to known objects can be plotted on a map to find the location.

Compare using a GPS or M&C in heavy fog or when it is too dark to see any reference points. To navigate in fog on featureless snow with M&C, it is common practice to use wands to create reference points--not needed with a GPS.

I've navigated a sailboat in coastal waters hunting for a buoy in a fog bank using only chart and compass. Its hard work and risky business--I sure wish I had had a GPS or Loran.

I personally find either the GPS or M&C easy to use, the difficulties are in the details. And the combination of both is better than either alone.


A couple of weeks ago on the Baldfaces, we got a little confused by the signs on NBF. We were going the correct way and had not missed any turns, we just though we were somewhere else. This became apparent over the course of a mile or so as the trail did not turn down the ridge as we expected it to. I pulled out my compass, oriented the map and was able to determine that we were still on the main ridge running N/S and had not in fact turned down the trail heading East. We probably could have figured it out with just the map, but the compass helped to be certain. So, it may come in handy from time to time, even in the summer on (poorly/confusingly) marked trails. :D
A quick glance at a GPS would have also answered the question.

IMO, it is worthwhile to know how to use all three tools--they complement each other when used in combination. And if any of the three fail or are lost, the others can fill in the void.

Doug

DougPaul
07-07-2006, 12:01 AM
Well, now you've gone and done it. You just had to smoke me out on magnetic bearings, didn't you?
Sorry...


Orienteers draw a series of parallel "north lines" on their maps, aimed at magnetic north and using as a guide the declination diagram found on any decent topo map. They space the lines at intervals convenient for the size of the map and the size of their compass baseplates. Then they never, ever worry about declination. They just use the lines to locate "North" on the map for compass purposes and off they go.

You can do the same thing to your maps in the comfort of your home before you go into the woods, if you don't mind marking them. (I do. Mind, that is.)

Why am I reluctant to pass on this tip? Mostly because I think you're better off in the long run understanding declination and how to compensate for it. But I might be in a very small minority on that point.
Yes, I know about drawing a magnetically aligned lines--don't like to do it either. My compass has automatic declination--set it and forget it. (I navigate in true bearings on land. I also use my maps north up and don't need to orient them to the terrain around me.)

NG TOPO! will print out maps with grids, but it looks like they are true orientation only. (Seems like including a magnetic orientation might be a nice option for the line-drawers.)

Doug

onestep
07-07-2006, 05:16 AM
Orienteers draw a series of parallel "north lines" on their maps, aimed at magnetic north and using as a guide the declination diagram found on any decent topo map.

You can do the same thing to your maps in the comfort of your home before you go into the woods, if you don't mind marking them.

I have a drawer full of maps with red parallel magnetic north lines on them. It's a night before the 'whack tradition.

This morning I'm heading up to Jackman for 3 days of bushwhacking. I'm going to try something different. My compass does not have an adjustable declination feature. I'm going to use the *true* north grid lines from the map. That means when I set a bearing from the map I'll have to add the declination to the compass... Add Map to Compass... AMC right?

Onestep

Nessmuk
07-07-2006, 06:03 AM
Orienteers draw a series of parallel "north lines" on their maps, aimed at magnetic north and using as a guide the declination diagram found on any decent topo map. They space the lines at intervals convenient for the size of the map and the size of their compass baseplates. Then they never, ever worry about declination. They just use the lines to locate "North" on the map for compass purposes and off they go.

You can do the same thing to your maps in the comfort of your home before you go into the woods, if you don't mind marking them. (I do. Mind, that is.)This is precisely what I do and have taught for years. All my maps have magnetic north lines drawn on the region of interest, spaced the width of a yardstick. There is never any math to be done, no fiddling around with the declination compensation screw. A 59 cent grade school protractor and yardstick does the trick. Preparing maps like this is a good way to also spend some time on studying the terrain before you go. In the field it is not necessary to orient the map to land (though it may be helpful and instructional where you have a vista). All references to map and field are magnetic. The technique is described in the reference document given by Neil.

I have a supplement to the above mentioned reference document, which is a two page graphic in pdf format. It graphically summarizes everything you need to know about using a compass and map together, including this technique. The problem is that it is almost a Mb in size and cannot be posted here. Are there any alternatives? I suppose I could email it if you PM me.

sleeping bear
07-07-2006, 09:19 AM
A GPS directly gives you location, altitude, time, and direction and speed of movement (a 7-tuple: 3 dimensions of position, 3 dimensions of velocity, and 1 dimension of time). (A mapping GPS can also plot your location and track directly on a map for you.) A compass directly tells you only directions (bearings). A set of bearings to known objects can be plotted on a map to find the location.



A map, compass, and some awareness of your environment will tell you (pretty much) all of these things too, you just have to pay attention.

It is true that a quick glance at the GPS would have given us the same info on the baldfaces as the map and compass. In fact, it would have given us a more precise answer to the question of "where are we?". However, we didn't need to know where we were to the nearest foot, we just need a general idea, and that's what we got. Neither a GPS, nor compass was entirely necessary at that point, as we would have figured it out pretty quickly even with just the map. I was only pointing out that a compass can be usefull, even in the summer on marked trails. Someone a few posts back said one was probably not 100% necessary for that type of travel.

Despite all that, I do agree that a GPS can be a useful tool, and that when used in conjunction with a map, compass it's darn near impossible to get lost, which opens up a lot of off-trail possibilities.

Kevin Rooney
07-07-2006, 09:46 AM
This morning I'm heading up to Jackman for 3 days of bushwhacking. I'm going to try something different. My compass does not have an adjustable declination feature. I'm going to use the *true* north grid lines from the map. That means when I set a bearing from the map I'll have to add the declination to the compass... Add Map to Compass... AMC right?

OnestepNo, you'll substract the declination in Jackman - here's a reference. (http://www.learn-orienteering.org/old/declinrhyme.html)

Neil
07-07-2006, 10:00 AM
It's always interesting how discussions like this one inevitably lead to "gps vs. map and compass".

I get much more satisfaction out of getting from A to B successfully with M&C than with gps. But, for some long, complicated bushwhacks that require fairly precise checkpoints and route changes the gps is a great backup. If used in lieu of M&C the gps saves time (at least in my case).

There's something special and undefinable that I like about pre-trip map study, then reading the terrain, reading the map and using the compass, perhaps an altimeter and a watch.

What is really cool is recording your route on a gps and viewing it on the computer afterwards. :)

sardog1
07-07-2006, 10:24 AM
No, you'll substract the declination in Jackman - here's a reference. (http://www.learn-orienteering.org/old/declinrhyme.html)

Sorry, but this is an example of why the mnemonic tricks often fail. The correct answer to onstep's question is indeed to ADD the declination.

The USGS has published this lesson (http://education.usgs.gov/common/lessons/how_to_use_a_compass_with_a_usgs_topographic_map.h tml) to help:

How To Use a Compass with a USGS Topographic Map

Method #1: (these directions assume your orienting arrow lines up with the North indicator on your compass dial, meaning the compass has not been adjusted for declination).

A) Obtain the local magnetic declination for the area represented on your map. At the bottom of every USGS map is a diagram that displays the difference & direction between true north (represented as a star), grid north (abbreviated as “GN”), and magnetic north (abbreviated as “MN”). Magnetic declination is the number of degrees and direction between true north and magnetic north. Because declination varies over time, it is advisable to get a reasonably current figure. If your USGS map is more than 15 years old (the declination date appears in the diagram), here’s an easy-to-use website that gives you only the information you need for your specific area:

http://gsc.nrcan.gc.ca/geomag/field/mdcalc_e.php

If magnetic north is east of true north, the local declination is positive.

If magnetic north is west of true north, the local declination is negative. (NOTE: This is the situation in Maine and all the rest of the Northeast.)

B) Draw a line on the map that connects your starting point with the destination (your “map bearing”). Extend the line all the way through the map border (the “neat line”).

C) Distance yourself from any nearby metal such as keys, belt buckle, desk, car, fence, etc. Place the compass on the map so the needle’s pivot point is directly over the intersection of your map bearing and neat line.

D) Rotate the dial until compass ring north agrees with map north. Read your map bearing from the compass dial. Make sure the bearing agrees with your direction of travel – for example, if you intend to travel due east, the bearing is 90 degrees, not 270 degrees.

E) Do this step mentally – don’t turn the compass dial. If the local declination is positive, then subtract the declination amount from the bearing you just derived. If the local declination is negative, then add the declination amount to the bearing you just derived. (So, if you're in Jackman, Maine, where the declination is negative (i.e., the magnetic needle points to the left of true north), then you'll ADD to the map bearing.)

F) Turn the compass dial until the figure you calculated in step E lines up with the index line.

G) Lift the compass off the map, and with the direction of travel arrow pointing directly away from you, rotate your body and the compass all in one motion until the red magnetic needle overlays the orienting arrow.

H) Sight a landmark along this bearing, and proceed to it. Repeat this step until you reach your destination.

Method #2: (these directions assume your orienting arrow lines up with the North indicator on your compass dial, meaning the compass has not been adjusted for declination).

A) Obtain the local magnetic declination for the area represented on your map. At the bottom of every USGS map is a diagram that displays the difference & direction between true north (represented as a star), grid north (abbreviated as “GN”), and magnetic north (abbreviated as “MN”). Magnetic declination is the number of degrees and direction between true north and magnetic north. Because declination varies over time, it is advisable to get a reasonably current figure. If your USGS map is more than 15 years old (the declination date appears in the diagram), here’s an easy-to-use website that gives you only the information you need:

http://gsc.nrcan.gc.ca/geomag/field/mdcalc_e.php

If magnetic north is east of true north, the local declination is positive

If magnetic north is west of true north, the local declination is negative.

B) Draw a line on the map that connects your starting point with the destination (your “map bearing”).

C) Distance yourself from any nearby metal such as keys, belt buckle, desk, car, fence etc.

D) Place the compass on the map so the baseplate is parallel to the line you drew. Make sure the direction of travel arrow points to your destination.

E) Rotate the dial until compass ring north agrees with map north. Do not move the compass when you rotate the dial.

F) Remove the compass from the map and, with the direction of travel arrow pointing directly away from you, rotate your body and the compass all in one motion until the red magnetic needle overlays the orienting arrow.

G) If local declination is positive, then subtract the declination amount (turn the dial clockwise). If local declination is negative, then add the declination amount (turn the dial counter-clockwise). (Again, if you're in Jackman, Maine, where the declination is negative (i.e., the magnetic needle points to the left of true north), then you'll ADD to the map bearing.)


H) Again, with the direction of travel arrow pointing directly away from you, rotate your body and compass all in one motion until the red magnetic needle overlays the orienting arrow. Sight a landmark along this direction of travel and proceed to it. Repeat this step until you reach your destination.

Nessmuk
07-07-2006, 10:32 AM
I have a drawer full of maps with red parallel magnetic north lines on them. It's a night before the 'whack tradition.

This morning I'm heading up to Jackman for 3 days of bushwhacking. I'm going to try something different. My compass does not have an adjustable declination feature. I'm going to use the *true* north grid lines from the map. That means when I set a bearing from the map I'll have to add the declination to the compass... Add Map to Compass... AMC right?

OnestepWhat map has *true* north grid lines already on it? If you are using a USGS topo map, do not confuse the UTM grid lines with true north, they are not the same. The only true north on the map is at the edges, the longitude meridians. There may be 4 "+" marks also on the map interior that you can draw meridians and parallels through, but no grid lines. For practical purposes you may get away with using the UTM grid lines, as by definition they are never more than +/- 3 degrees from true.

To use another reference system, use logic instead of forgettable word games that can get you off course by double the declination if not applied correctly. Think of where on the globe the magnetic north pole is in Canada... thus if I am east of Chicago then the magnetic north lines tilt left. The little diagram on the bottom of some (not all) topo maps depicts this graphically.

Therefore, if I am actually facing true north, then my compass needle will point to my left, and after "boxing the needle" I will be reading, say for example, 014 degrees (the map's published declination) on the compass. That concept of what your compass reads when you face true north gives you the answer and a way to logically convert to any other direction.

This means if I want to head in the direction of 000 true, I must go in the direction of 014 magnetic by my compass. If I want to travel 020 true, then I must go 020+014=034 magnetic. If I want to travel 270 true, then I must set the compass to 270+014=284 magnetic. To go 350 true, set 350+14=004. Simple and unforgettable because you know how to derive the answer with logic, not memory.

I find it far easier to do my map study, draw the mag north lines, and there's my reference permanently set. No math, no converting to another reference system, no fuss, no errors at the end of a long day's slog through the woods.

DougPaul
07-07-2006, 11:31 AM
What map has *true* north grid lines already on it? If you are using a USGS topo map, do not confuse the UTM grid lines with true north, they are not the same. The only true north on the map is at the edges, the longitude meridians. There may be 4 "+" marks also on the map interior that you can draw meridians and parallels through, but no grid lines. For practical purposes you may get away with using the UTM grid lines, as by definition they are never more than +/- 3 degrees from true.
There is grid north, true north, and magnetic north. All different. (All should be shown in the declination diagram on USGS topos.) Grid north is usually close enough to true north in the continental US for hikers to use either one. (The difference is larger in northern Alaska and northern Canada.)



<logic snipped> Simple and unforgettable because you know how to derive the answer with logic, not memory.
Different methods work best for different people. I personally like logic, others prefer rules-of-thumb. I prefer to hold a map north-up and rotate to match the world in my head, others perfer to rotate the map to match the world. Whichever--as long as it works when you need it.


I find it far easier to do my map study, draw the mag north lines, and there's my reference permanently set. No math, no converting to another reference system, no fuss, no errors at the end of a long day's slog through the woods.
Remember that conditions where you really need the compass may include fatigue, panic, zero visibility, wind, precip, threat of hypothermia, etc. It becomes easy to make a mistake under these conditions (particularly when using logic or rules of thumb) and therefore I think that it is a good idea to use methods which eliminate the need for the conversion: ie automatic declination on the compass (my preference) or predrawn magnetic north lines (Nessmuk's preference).

Ultimately the goal is not my method is better than your method or for everyone to use a single method--it is for everyone to have a bomb-proof method that works for them when needed.

KISS (Keep It Simple Stupid).

Doug

Rick
07-07-2006, 11:33 AM
Sorry, but this is an example of why the mnemonic tricks often fail. The correct answer to onstep's question is indeed to ADD the declination....
Hence my earlier comment that it takes work, knowledge and PRACTICE to really operate a compass. It is easy to learn this stuff but if you don't use it or practice it for 4-5 years and then find that all you can remember is "East is Least West is Best" (I think that even came in my Silva Ranger Compass directions), you might be in trouble - Then again, as Sardog mentions, Call someone on your cellphone and have them honk a horn from the Trailhead!! :D

DougPaul
07-07-2006, 11:43 AM
Then again, as Sardog mentions, Call someone on your cellphone and have them honk a horn from the Trailhead!! :D
Not foolproof either--sound does not always travel in nice straight lines. I have been at sea in a heavy fog when the sound of a lighthouse horn would seem to come from one direction at one moment and then from another a bit later.

Sound can be bent by wind and thermal gradients and reflects off large objects.

Doug

DougPaul
07-07-2006, 11:54 AM
The USGS has published this lesson (http://education.usgs.gov/common/lessons/how_to_use_a_compass_with_a_usgs_topographic_map.h tml) to help:

How To Use a Compass with a USGS Topographic Map
<snip>
While I'm sure this lesson is quite accurate, it is rather complex. An occasional compass user, even with some initial practice, is likely to have difficulty remembering it sometime later under stressful conditions.

And the statement

If magnetic north is east of true north, the local declination is positive.
If magnetic north is west of true north, the local declination is negative.

is just a rule-of-thumb with no memonic to help one remember it. (I have trouble remembering it here at my keyboard, let alone in the woods.)

Again, I vote for KISS (Keep It Simple Stupid). (See my post #44.)

Doug


PS. This thread has come a long way from "recommendations for a beginner's compass".

sardog1
07-07-2006, 12:08 PM
While I'm sure this lesson is quite accurate, it is rather complex. An occasional compass user, even with some initial practice, is likely to have difficulty remembering it sometime later under stressful conditions.

And the statement
is just a rule-of-thumb with no memonic to help one remember it.

Again, I vote for KISS (Keep It Simple Stupid).

Doug

I agree that the lesson is complicated. I posted it only to document step-by-step why onestep should be adding at Jackman.

In order of complexity, here's how to deal with declination:

1. Draw the north lines on the map and fuhgedaboudit.

2. Buy a compass with a set screw compensation and remember to set it properly any time you change locations by a signficiant east-west difference, e.g., from NH to ME or VT to NH.

3. Buy a compass with a compensation in the dial that you set by turning a capsule in the dial. Remember to set it properly and to check it while you're in the field in case you move the compensating capsule.

4. Admit you're a masochist and practice using the USGS lesson. Remember that to go from map to compass and compass to map are the opposite and require opposite compensations. :eek:

5. Use a mnemonic and carry extra food and water for the inevitable occasion(s) when you mess up. :confused:

Nessmuk
07-07-2006, 12:43 PM
Again, I vote for KISS (Keep It Simple Stupid).In the final analysis, ALWAYS navigate by making sense out of the terrain and observational clues provided to you. Only when paddling in a dense and overcast fog on a vast windless lake do you only have the compass to follow. Terrain navigation clues abound with every step here in the NE woods. If any one of them does not make sense with the others (including the compass), stop and figure out why not before proceeding. Learn how to spot and correct errors early. Making sense out of your sourroundings is the most basic of all KISS navigation principles.

Nessmuk
07-07-2006, 12:48 PM
PS. This thread has come a long way from "recommendations for a beginner's compass".That's because there is so much more critical information necessary to successful navigation than picking out the "right" compass.

DougPaul
07-07-2006, 12:59 PM
In the final analysis, ALWAYS navigate by making sense out of the terrain and observational clues provided to you. Only when paddling in a dense and overcast fog on a vast windless lake do you only have the compass to follow. Terrain navigation clues abound with every step here in the NE woods. If any one of them does not make sense with the others (including the compass), stop and figure out why not before proceeding. Learn how to spot and correct errors early. Making sense out of your sourroundings is the most basic of all KISS navigation principles.
Of course--always use multiple sources of navigation info if they are available to you.

But the thread topic was choosing a compass (affected by issues of how to use it), not general priciples of navigation.

Doug

ksullnh
07-07-2006, 05:13 PM
On a separate note, if your background is in sailing, it's important to note that the "declination" we landlubbers refer to is usually "variation" on a boat.

As far as correcting compass error, which is the goal, I tend to use the colorful PG-13 sailing term, "True Virgins Make Dull Company, Add Whiskey" which tells you the order: True, Variation (hike declination), Magnetic (North), Deviation (the effects of the boat or other metal stuff on the magnetic compass), Compass (the bearing on the compass at the helm). "Add Whiskey" means "Add West"....

There shouldn't be any deviation in the woods, unless you have a really big belt buckle from an ultramarathon/rodeo, old school steel exterior frame pack, or are under a radio tower, so Magnetic and Compass are synonymous.

So if your hike-declination (variation) is listed as 16 degrees west, you add it to true north if you're going from left to right ((T->V->M/C) True North - Compass reading), or subtract it if you go from right to left (T<-V<-M/C). The corollary would be to subtract east land-declination (variation) when going from T->M/C, or add when going from M/C->T.

This is probably confusing, so any erstwhile sailors can pull out their Bowditch for a more thorough explanation.

have fun,

kevin

PS: the more G-rated mnemonic is "Can Dead Men Vote Twice, At Elections?" for Compass, Deviation, Magnetic, Variation, True... Add East.

Paradox
07-07-2006, 05:54 PM
Dear Toe Cozy,
Many handheld GPS units have an integral fluxgate compass. The compass in my Garmin 60CSx is somewhat more stabile in non-level conditions than the Timex watch I bought about 5 years ago and the Auto-Helm flux-gate hand bearing compass I bought about 10 years ago when I was an avid around-the-bouys small sailboat racer. Magellin claims that their compasses have excellent non-level stability. I have a Magellin Platinum that has a very stabile flux-gate compass (though I may have used it twice at most). The compass in my Garmin Vista is horrible and will vary 90 degrees of heading with 5 degrees of tilt. Pick up a 60CSx and see if you use the compass alot or use the GPS most of the time.

DougPaul
07-07-2006, 06:19 PM
On a separate note, if your background is in sailing, it's important to note that the "declination" we landlubbers refer to is usually "variation" on a boat.
To complete the list of confusing terms, there is also magnetic inclination (or dip angle)--the (vertical) tilt angle of the field. 0 deg at the magnetic equator, 90 deg at the magnetic poles.

A non-zero inclination will push one needle point up and the other down and could cause it to drag on the compass capsule. To prevent this, the earth has been divided into 5 zones, and compass needles have been balanced to work with each zone. Thus, a compass bought for use in N America may not work in S America. Some manufacturers make a "global" compass (eg http://www.rei.com/online/store/ProductDisplay?storeId=8000&catalogId=40000008000&productId=3276566&parent_category_rn=4500598&vcat=searchrefine) which can be used anywhere.

Most users need not worry about this issue--all of the US (except Hawaii), Canada, Euope, and northern Asia are in the same zone and compasses sold within the zone will work within it.

For more info including zone maps see http://www.wide-screen.com/support/FAQsuunto.shtml

Doug

DougPaul
07-07-2006, 06:49 PM
Many handheld GPS units have an integral fluxgate compass. The compass in my Garmin 60CSx is somewhat more stabile in non-level conditions than the Timex watch I bought about 5 years ago and the Auto-Helm flux-gate hand bearing compass I bought about 10 years ago when I was an avid around-the-bouys small sailboat racer. Magellin claims that their compasses have excellent non-level stability. I have a Magellin Platinum that has a very stabile flux-gate compass (though I may have used it twice at most). The compass in my Garmin Vista is horrible and will vary 90 degrees of heading with 5 degrees of tilt. Pick up a 60CSx and see if you use the compass alot or use the GPS most of the time.
Garmin claims +-2 degree accuracy (+- 5 deg in extreme northern and southern lattitudes) with proper calibration for both the Vista and 60CSx. (They don't say if you need to bring a bubble level with you...)

The batteries in a GPS are magnetic, so there is a simple calibration procedure to calibrate the compass any time the batteries are changed or disturbed. (Currents in the wires also creat small magnetic fields which might also degrade accuracy.)

Magellan uses a 3-dimensional sensor and I have read on sci.geo.satellite-nav that Garmin uses a 2-dimensional sensor. (The eTrex Vista, but not the 60 series existed at the time. I have seen no comments on the 60 series sensors.) If this is indeed true, a GPS with a 2D sensor would be more sensitive to orientation than a GPS with a 3D sensor.

For comparison, when I make sightings with my magnetic compass (Silva Ranger CL, mirror, auto-declination, http://www.rei.com/online/store/ProductDisplay?storeId=8000&catalogId=40000008000&productId=737&parent_category_rn=4500598&vcat=searchrefine) whose accuracy can be checked, my error is generally less than a degree.

The magnetic compass on a GPS significantly increases the battery drain--most users turn it off except when actually using it.

Doug

sardog1
07-08-2006, 07:58 AM
There shouldn't be any deviation in the woods, unless you have a really big belt buckle from an ultramarathon/rodeo, old school steel exterior frame pack, or are under a radio tower, so Magnetic and Compass are synonymous.

Well, almost. There are many places in North America with known anomalies, i.e., places where a compass needle will point somewhere other than magnetic north. From Magnetic Declination -- Frequently Asked Questions (http://www.geocities.com/magnetic_declination/), by Chris M. Goulet, Alberta, Canada:


A few areas with magnetic anomalies (there are thousands more):

-North of Kingston, Ontario; 90° of anomalous declination.
-Kingston Harbor, Ontario; 16.3° W to 15.5° E of anomalous declination over two kilometers (1.2 miles); magnetite and ilmenite deposits.
-Near Timmins, Ontario, W of Porcupine.
-Savoff, Ontario (50.0 N, 85.0 W). Over 60° of anomalous declination.
-Michipicoten Island in Lake Superior (47.7 N, 85.8 W); iron deposits.
-Near the summit of Mt. Hale, New Hampshire (one of the 4000-footers, near the Zealand Falls hut on the Appalachian Trail) ; old AMC Guides to the White Mountains used to warn against it. (Not just "old" WMG warnings. In the 27th edition, p. 177: "Many of the rocks around the former fire tower are reputed to be strongly magnetic." Anybody have any anecdotes to relate?)
-Around Georgian Bay of Lake Huron.
-Ramapo Mountains, northeastern New Jersey; iron ore; compass rendered useless in some areas.
-Near Grants, New Mexico north of the Gila Wilderness area; Malpais lava flows; compass rendered useless.

The USGS declination chart of the USA (GP-1002-D) shows over a hundred anomalies. The following table lists the most extreme cases.

Anomalous declination(degrees) Lat. Long. Location

46.4 W -- 40.2 106.2 75 km.(45 mi.) W Boulder, Colorado
24.2 E -- 40.7 75.3 20 km. (12 mi.) NE Allentown, Pennsylvania
16.6 E to 12.0 W over 10km(6mi) -- 46.7 95.4 250 km. (150 mi.) NW Minneapolis, Minnesota
14.8 E -- 33.9 92.4 85 km. (50 mi.) S Little Rock, Arkansas
14.2 E -- 45.5 82.7 In Lake Huron, Ontario
13.8 W -- 45.7 87.1 Escanaba, on shore of Lake Michigan
13.7 E -- 48.4 86.6 In Lake Superior, Ontario
13.5 E -- 48.5 122.5 80 km. (50 mi.) N Seattle, Washington
13.0 W -- 42.2 118.4 In Alvord Desert, Oregon
12.2 W -- 38.9 104.9 10 km. (6 mi.) W Colorado Springs, Colorado
11.5 E -- 47.8 92.3 120 km. (75 mi.) N Duluth, Minnesota

DougPaul
07-08-2006, 09:43 AM
A few areas with magnetic anomalies (there are thousands more):
The Katahdin tableland is also reported in older copies of the Maine Mtn Guide to have magnetic anomalies. We were required to carry wands when we were there in winter (~1980).

Doug

TomD
07-10-2006, 08:41 PM
I have a small collection of compasses. My favorite is a Silva 27-a small mirror compass. I also have a Suunto MC-2G which works anywhere (N or S hemisphere) because the needle is weighted for either and a couple of other little ones.

A good book is the Sierra Club's Land Navigation Handbook by W.S. Kals; also check out this website- http://www.learn-orienteering.org/old/ for some basic lessons and also check out the various orienteering sites for info on thumb compasses they use during orienteering races.

Remember, a GPS unit may be more accurate and easier to use, but a compass won't ever run out of power. Once you know how to use a compass and map, getting lost shouldn't be a worry.

nickdu
08-01-2006, 12:27 PM
There are different kinds of compasses too.

I use a
Brunton 8096 (http://www.amazon.com/gp/product/B000059HMJ/002-2658622-8667246?v=glance&n=3375251)

Jay

On the link you provided it shows that compass as Brunton 8096 Eclipse Compass. On REI I see a Brunton 8096-AR. I assume they are the same. I do see an Eclipse on REI but it's a 8099.

Pete_Hickey
08-01-2006, 12:38 PM
Just about any compass will w2ork, as long as you don't get a Tate's. They are the worst.

Jay H
08-01-2006, 01:18 PM
I think they are the same... However, it is a dated compass, I think I bought it when it was actually called a "GPS compass" because it has the little round circles to tell you how close you are given that SA was turned on. Based on the scale and GPS coordinates, you would mark your position and use the circles to give you a rough estimate of your worst case scenario. It's kind of moot now though. I can only guess the "AR" that REI uses is for Adventure Racing, cause it includes a UTM grid. All Adv. races I've done used UTM for the orienteering. However, there are better UTM grids than one stuck on the compass, it's better to have a dedicated UTM grid that is much easier to use to mark orienteering or topo maps with.

Jay

RoySwkr
08-01-2006, 07:20 PM
Nice to meet you, TC

If you can spare a dollar or two, buy one of the miniature compasses and fasten it to a pack strap. One of my friends did this who used to just plod up trails without any clue of which way she was going, with it so handy now it's trivial to get a feel for which way she's going and she wants another for her car. For someone who previously didn't know if they were going N or S, why worry about a few degrees declination? Use the compass & map to get a feel for how a trail goes, then you will understand what a similar off-trail route might be like. Go to an orienteering meet, for a few bucks you get an accurate map with compass lessons and a rental compass if you need them.

Serious bushwhackers will want a spare compass, the one from your pocket can get snatched away by a twig or left in the car while packing up so it's good to have a spare in your first aid kit.

Most of my bushwhacking is to obvious points such as peaks so I rarely even look at a compass anymore but just follow the terrain or the sun. I knew a guy who had hiked all over the Belknap Range before the trails were built and he didn't even carry a compass because he thought it was too difficult to understand. I offered to teach him and said anybody who could balance a checkbook could figure out a compass, and he said he just figured the bank got it right.