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Using lines of position to fix your location on a map


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Home Forums Campfire Editor’s Roundtable Using lines of position to fix your location on a map

Viewing 25 posts - 1 through 25 (of 35 total)
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  • #3753858
    Ryan Jordan
    Admin

    @ryan

    Locale: Central Rockies

    Companion forum thread to: Using lines of position to fix your location on a map

    Learn how to identify and use lines of position to help fix your location on a map while traveling in the backcountry.

    #3753926
    Eric Kammerer
    BPL Member

    @erickammerer

    I must be getting old — I thought this was standard practice.

    Do people really only rely upon a GPS fix? Absolute reliance on an electronic device and associated systems (satellites, battery pack, etc.) — and with no backup option?

    #3753928
    Ryan Jordan
    Admin

    @ryan

    Locale: Central Rockies

    For my clients that meet with me 1-on-1 for private instruction, map-and-compass use has always been the #1 request. Which makes me happy – but I’m still in awe at the number of hikers I meet who just follow the alltrails location marker/arrow…

    #3754001
    Jeff McWilliams
    BPL Member

    @jjmcwill

    Locale: Midwest

    Pretty good stuff.  I’ve been helping teach map & compass workshops to our local outdoors club for about 10 years, and am active in our local orienteering club as well.  We use “Linear Position” where you use LOP.  Same thing.

    #3754007
    Virginia R
    BPL Member

    @gr

    Really enjoying this content, thank you!

    #3754013
    Ray J
    BPL Member

    @rhjanes

    Good stuff.  As in the other thread, in Orienteering we call the Linear Features “Handrails”.  Something that can be followed in a compass direction until you reach a finite point (The trail crossed the power line in the middle of a thicket, 2 miles from camp).  These features are also used as “Catch feature”.  Say you are using the water channel, going NNW and were shooting/looking for some other feature (control in Orienteering speak) and there is say an oil pipeline some short distance beyond the feature.  You are following the water feature/creek and hit the oil pipeline.  OOPS!  You know you have overshot as the “Catch feature” (also a linear feature) just showed up.  But you also know right where you are!  You are at the creek crossing the pipeline.  Take a compass bearing, measure the distance (if you need) and pace count your way back to the feature you were shooting at.

    #3754015
    Jeff McWilliams
    BPL Member

    @jjmcwill

    Locale: Midwest

    Ryan did actually mention handrails in the article, and we use that term as well.  Are all handrails linear features and are all linear features handrails?  Hmm.  I’d have to ponder whether I agree that’s true.

    Catching features don’t necessarily have to be linear.  Here in SE Michigan, our orienteering courses have a lot of notable depressions, ponds, and vernal ponds, because our topography was formed by glaciers thousands of years ago that formed kames, kettles, eskers, etc.   I’ve often used them as catching features, but I wouldn’t consider them linear.

     

    #3754389
    AK Granola
    BPL Member

    @granolagirlak

    Most of the under 30 hikers I know only use phone apps with GPS. They don’t even think about maps. Our major map source in town just closed down permanently. Very sad, because they had every map for everywhere in Alaska you could want. I had the lovely experience recently of teaching some map reading skills to some kids on a backpacking trip. Not sure they’ll remember or ever use it again though. But they were interested that I could read the map and tell them how much climbing we were going to be doing the next day, and where good view spots might be. Glad I learned orienteering when young. That said, I’m pretty rusty with compass these days!

    #3754393
    Todd T
    BPL Member

    @texasbb

    Locale: Pacific Northwest

    I’ll switch to GPS when the screen is as big and lightweight as my paper map, as easy to read in bright sun, and allows hand-writing notes that stay with the displayed map.  Oh, and the batteries last two weeks with the GPS on 24/7, on a single charge.  No luddite here!

    #3754401
    John “Jay” Menna
    BPL Member

    @jaymenna78734

    Locale: 30.3668397,-97.7399123

    Don’t forget when you can tear off half the GPS  (Preferably the half you have already treked) and use it to start a fire.

    #3754408
    Ray J
    BPL Member

    @rhjanes

    Jeff M, Excellent point about Catching features not necessarily needing to be linear.  I agree.  I’ve used buildings and such.  Linear features are just, for me, easier to spot.  I usually need something catching that is large.  River, cliff, building, pipeline/powerline.  Stuff like boulder clusters often don’t work for me as some of our Texas venues are FULL of boulders.  We’ve had running jokes about SID Richardson Scout ranch and the clues there.  “Boulder, Boulder Cluster, Stony Ground, Between two boulders, On top of a 2 Meter boulder…….”

    #3754410
    Paul Wagner
    BPL Member

    @balzaccom

    Locale: Wine Country

    I’m with Eric.  I learned this stuff decades ago when I was sailing on a regular basis.  If you think this matters in the woods, you should try it a trackless stretch of water that is moving underneath you.  Getting a fix on those distant points of land makes all the difference.

    It’s harder to do this stuff in a dense forest…but this is still my primary navigational system, if you don’t count the trail signs themselves.

    Someday I’ll get a GPS, I guess…

    #3754431
    Johan
    BPL Member

    @johan-river

    Locale: Cascadia

    Good to see there are still some people pushing for compass skills. Very useful.

    On top of taking a paper map and compass, I also do my entire route in Google Earth, pre-trip. I burn the entire area into my brain as a mental 3D map. Google Earth allows you to also get an idea of what every prominence looks like from the ground. If I was teleported to any spot within the area I am backpacking, I could probably gain a lot of intel just from looking at the terrain and vegetation and comparing it to my mental 3D render from flying around Google Earth for several hours.

    #3754442
    Jim Cowdery
    BPL Member

    @james-cowdery

    Locale: South Florida

    Through the years I have owned two or three gps units.  To me they are more of a curiosity than a tool I use when hiking.   They are heavy and have short battery lives.

     

    A better electronic tool is an altimeter.  There are many versions that last over a year on one battery and also will give you the time of day!

    I always hike with a paper map and keep it in my pocket for quick references.  With a map, compass and altimeter I can usually pinpoint my location accurately.  Orienteering is a necessary skill for  backcountry activities.

     

    #3754444
    Bill in Roswell
    BPL Member

    @roadscrape88-2

    Locale: Roswell, GA, USA

    Compasses – My pack with old Silva compass was stolen last year (car breakin). It had declination adjustment. Did research for a new compass. Now to get declination adjustment the mfg charge a premium. The standard Suunto M3 D is a whopping $73 for what used to be a common compass. Since my background is geography and mapping, I got the Suunto MC2 Pro, also $73. No wonder everyone under 40 uses phone GPS only! And so do most over 40.

    #3754458
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    No wonder everyone under 40 uses phone GPS only! And so do most over 40.
    I don’t quite see this.
    You can find perfectly satisfactory Chinese base-plate compasses on ebay for around $11.
    You can even get a Coghlans baseplate compass for $12.34 on ebay.
    So worries about the sky-high prices some places are charging seem a shade pointless. Shop around!

    Advice: do NOT buy anything which is not fluid-filled. And beware of the extremely small button compasses: they can take ages to settle. Some of them just jam up.

    Cheers

    #3754459
    jscott
    BPL Member

    @book

    Locale: Northern California

    wow this thread is flushing out all the luddites (elders?) like me. I’ve probably seen you at a jazz concert.
    I won’t bother to calculate the entire weight of a gps/battery/solar charger ensemble that seems to be de rigueur these days. That said, I’ve been forced to concede that a phone makes a good camera, and as long as you have that, why not add gps?

    My response has been to go camera-less. I spent fifteen years lugging camera equipment and have all the slides I’ll ever need already.

    Map and compass? 2-3 ounces? fail proof, in terms of technology. No batteries required. It’s a beautiful thing.

    edit: yeah, wow, $73.00 for a compass is prohibitive, impossible…as compared to what, a single outer layer? or a phone? it’s not like the damn thing is going to wear out.

    #3754460
    David Thomas
    BPL Member

    @davidinkenai

    Locale: North Woods. Far North.

    My favorite bit of navigation equipment is a high-quality altimeter.  

    in combination with a ridgeline, ascending trail or river, you know exactly where you are.  Of course your watch and your phone have altimeters in them now too, so if you keep it adjusted, that’s a back-up to all your other tools.  Alas, like a compass, is most useful for finding your way home if you were using it on your way in.

    My biggest benefit from using an altimeter is that it doesn’t get overly optimistic.  It’s emotionally draining to think the destination is just over that next ridge, and then the next one, and the next one.  If camp is 9,600 feet and I’m at 8,000, I just need to settle in for another 1600 feet of climbing.

    #3754461
    Roger Caffin
    BPL Member

    @rcaffin

    Locale: Wollemi & Kosciusko NPs, Europe

    My favorite bit of navigation equipment is a high-quality altimeter.
    In principle I totally agree – in the right country.
    Around Sydney an altimeter is not that much use: the plateaus are flat, and the ‘valleys’ are lined with cliffs. But in the European Alps – oh yes, for sure! They go up and down a lot more.

    Cheers

    #3754463
    Ratatosk
    BPL Member

    @ratatosk

    I’m delighted to see this kind of content here.

    I’ve never heard the term ‘catch feature’, I’ve always used “handrail” to apply to a feature near my destination that I know I’m going to hit more or less perpindicular to my line of travel – a stream to cross, or a road, that I can hit a little below my line and then turn up, as a precaution against overshooting a destination. So now I’ve got a better vocabulary to work with.

    #3754477
    David Thomas
    BPL Member

    @davidinkenai

    Locale: North Woods. Far North.

    A concept different than “handrail” but also helpful is to intentionally aim left of your destination and then you know it is to your right.  That’s super helpful while boating and looking for a feature on the shoreline, but comes up in backpacking sometimes, too.

    Alas, I often remember that trick when I’m ping-ponging further and further from predicted dead center covering the same ground over and over.

    #3754478
    Jeff McWilliams
    BPL Member

    @jjmcwill

    Locale: Midwest

    David – we call that “aiming off”.

     

    #3754483
    Todd T
    BPL Member

    @texasbb

    Locale: Pacific Northwest

    David — we call that “deliberate offset.”

    #3754502
    Ray J
    BPL Member

    @rhjanes

    Orienteering, Handrail = something you can follow along.   Catch Feature = something that would stop you in your direction of travel (you find the creek, boulder, house, trail) but I often use a Catch Feature to STOP me when I’ve overshot on a bearing.  “I’m aiming off to the NNE, once I hit the trail (handrail), I’ll know to turn Left and follow it to the second drainage BUT if I hit the next trail (Catch Feature), I know I missed the drainage.

    #3754504
    Jeff McWilliams
    BPL Member

    @jjmcwill

    Locale: Midwest

    Roger – cheap Chinese compasses or Coghlan’s ones:

    Ugh.  Can I just say, “No thanks”?   Those cheap ones do not have a declination adjustment, and I do not like the cheaper compasses with a “declination scale”, which is not the same as adjusting the compass’s declination like Suunto has.

    Maybe for a lot of things, being off by a degree or two doesn’t matter.  In Yosemite, however, the declination is 12.6 degrees east.  With the error calculation being roughly 100 feet per degree per mile, walking a mile without adjusting for declination would put you 1260 feet off from your intended target.  In the central portion of the New Zealand’s south island, declination appears to be about 24 degrees east.

    Suunto compasses are my favorite baseplate compasses, but yes they are expensive.  Brunton used to made an “Eddie Bauer” compass with a dayglow green baseplate that had an okay declination adjustment.   You can still find it pretty cheap if you look around.  The Brunton TruArc 5 also has a decent declination adjustment.  The TruArc 3’s declination adjustment seems broken by design.

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