#224336 - 05/25/11 11:08 PM
Topo Maps
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Enthusiast
Registered: 08/17/09
Posts: 305
Loc: Central Oregon
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What does terrain association mean to you in land navigation? I am interested in your thoughts on this. Thank you, Blake www.outdoorquest.bizwww.outdoorquest.blogspot.com
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#224344 - 05/26/11 12:58 AM
Re: Topo Maps
[Re: Outdoor_Quest]
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Geezer in Chief
Geezer
Registered: 08/26/06
Posts: 7705
Loc: southern Cal
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I suppose a rough and ready definition would be visual reconciliation of the features (hills, bends in a stream, coastal shorelines, etc) shown on a map with the features visible from your position on the ground. If that big hill to my north is Mount Tremendous, and I am standing by the stream just to the south of that peak, I must be here. If so, then Crag Peak would be the hill to the west- yeah, that looks right. Mount Toil would be the mountain to the southeast - yeah, that fits. I know where I am.
Also helps in the intermontane west. You can see the Baldy Mountains in the distance and you know they are north of you. Therefore, you know where north (approximately)is without resorting to a compass.
Basically you form a hypothesis, test it by observation, confirm or reject. If rejected, try again, until everythingfits.
Edited by hikermor (05/26/11 01:31 AM)
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Geezer in Chief
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#224351 - 05/26/11 01:59 AM
Re: Topo Maps
[Re: Outdoor_Quest]
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Veteran
Registered: 12/14/09
Posts: 1419
Loc: Nothern Ontario
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I spent most of my life using compass and topo maps along with terrain association to help in finding my way. Using terrain association it really helps to pinpoint where you are on the map.
(Edit. Hikermore already explained what I was about to.)
Continuing on...
With the advent of Google Earth, I (and many others) use it to also to print maps of the intended area of travel as the details afforded with these maps along with the ability to rotate the view in any direction and to also show 3D views of the terrain makes for better route planning etc. Not to mention that many of the topo maps in my AO have not been updated for 20-30 years...if not more and do not show newer roads, trails etc whereas most Google imagery in this area is only a few years old and thusly more up to date in this aspect.
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Earth and sky, woods and fields, lakes and rivers, the mountain and the sea, are excellent schoolmasters, and teach some of us more than we can ever learn from books.
John Lubbock
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#224375 - 05/26/11 04:22 PM
Re: Topo Maps
[Re: Outdoor_Quest]
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day hiker
Addict
Registered: 02/15/07
Posts: 590
Loc: ventura county, ca
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i agree with and practice all of the excellent points above. i like to believe and trust what i can see while in the woods.
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“Everyone should have a horse. It is a great way to store meat without refrigeration. Just don’t ever get on one.” - ponder's dad
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#224469 - 05/27/11 09:22 PM
Re: Topo Maps
[Re: Outdoor_Quest]
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Sheriff
Pooh-Bah
Registered: 10/12/07
Posts: 1804
Loc: Southern California
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To me, it's two highly related, but slightly different disciplines: 1. Can I correlate what I see around me with what's on my map? ( map first terrain association) 2. Can I correlate what I see on my map with what's around me? ( terrain first terrain association) Two sides of the same coin, really. If I'm looking at my map trying to find something, I start with the map first and then look around me. The other side of the coin occurs as I walk along. I continually look around me. If I see a peak, saddle, or other distinctive land form, I identify it on my map. I find that identifying distinctive terrain features as I go keeps me constantly oriented. If I come upon the unexpected, I already have a good idea of where I am and am less likely to get confused. Case in point, on trip in the Rockies a few years ago, my buddy was doing terrain association, map first. He came to a trail junction. There was only one trail junction on our route in that area, but he couldn't quite get things to add up and was a bit confused. I on the other hand was doing terrain association, terrain first. I already knew approximately where we were based on terrain, and I figured it out in a split second: The trail had been re-routed, and the junction was no longer where it was shown on the map. Both sides of the "coin" (map first, terrain first) have their place, but for continuously staying oriented, my money is on terrain first. HJ
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#224473 - 05/27/11 09:32 PM
Re: Topo Maps
[Re: Hikin_Jim]
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Geezer in Chief
Geezer
Registered: 08/26/06
Posts: 7705
Loc: southern Cal
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Terrain features are much more of a constant than any man made features, especially trails. Even if they are depicted properly on the map (not always the case) they are moved, upgraded, etc. Sometimes not all roads or trails are even shown (think logging spur roads).
On the other hand, I used topo maps on the Channel Islands that were generated by the Army Map Service in 1943 from some of the very first aerial photogrammetry done in the US (Wonder why the Army was so interested in maps of the coast back then?). Even in 2000, the terrain was spot on, but the cultural features had changed considerably.
Edited by hikermor (05/27/11 10:01 PM)
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Geezer in Chief
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#224485 - 05/27/11 10:53 PM
Re: Topo Maps
[Re: Hikin_Jim]
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Geezer in Chief
Geezer
Registered: 08/26/06
Posts: 7705
Loc: southern Cal
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Hey, I've still got some of my dad's old War Department/AMS maps. Those were good maps. 1:62,500 is a little tough to do detailed land nav off of, but for multi-day trips it's nice to have the equivalent of four 1:24,000 map sheets on one smaller sheet of paper.
HJ Scale is critical. Years ago, we attempted a summit for which the only available map was an aeronautical chart. I can guarantee that a lot of critical features are not depicted at that scale...
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Geezer in Chief
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#224512 - 05/28/11 04:11 PM
Re: Topo Maps
[Re: hikermor]
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Sheriff
Pooh-Bah
Registered: 10/12/07
Posts: 1804
Loc: Southern California
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Scale is critical. Years ago, we attempted a summit for which the only available map was an aeronautical chart. I can guarantee that a lot of critical features are not depicted at that scale... Ooooh, yeah. And hiking in Alaska with only a 1:100,000 map, well, there's a bit of fun for ya. HJ
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#224762 - 05/31/11 03:06 PM
Re: Topo Maps
[Re: hikermor]
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Old Hand
Registered: 06/24/09
Posts: 714
Loc: Kentucky
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On the other hand, I used topo maps on the Channel Islands that were generated by the Army Map Service in 1943 from some of the very first aerial photogrammetry done in the US (Wonder why the Army was so interested in maps of the coast back then?). Answering an old question I missed before. I can't be sure about this, but is it possible that they were experimenting with making maps of the European coasts prior to d-day? 1943 would be about the right time, and I would think it would have been much easier to do map experimentation on friendly coastlines. Just a thought.
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