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Tilly
05-17-2010, 13:16
I don't know exactily where to post this question but I figured this would be the best forum.

For those that have hiked the CDT, PNT, or even the PCT, how/where/when did you learn your map, compass, GPS, and orienteering skills?

I would really like to learn how to find my way on lesser used trails. I have, um, a limited range of compass skills right now. What are some good books/classes that people have used? How did you get your route finding skills? Would you say that orienteering is different in the eastern forests vs. the wide open west? I am amazed at the route finding skills some people have. How can so many hike 30, 40 miles a day on a trail like the CDT or the NCT? I mean, isn't part of the day spent being misplaced and trying to calculate where to go and where you are?

Also, it is feasible to find your way in an isolated area with only a map and compass? I really hate the thought of buying and even learning how to use a GPS.

I would love to really expand my horizons a little. Thanks for any thoughts or advice.

IceAge
05-17-2010, 13:37
I think it is easier than you think.

I learned orienteering through the courtesy of the US Navy Seabees, but I'm sure there are decent guides online.

The only hard part about orienteering is figuring out where you are. If you are starting at an intersection or trailhead that is marked on the map you have, then you already have the hard part done.

The next step is to figure out the bearing to the next place you want to go. Then sight two landmarks along that bearing and off you go!

Best advice I can offer is to go to a big open county park and practice. Then go somewhere with some topographical variety and some trees and pratice some more.

Good luck!

Old Hiker
05-17-2010, 13:40
Learned mine in Boy Scouts. Any Scout Troop could help, probably.

Hikes in Rain
05-17-2010, 13:42
Get an old Scout manual or fieldbook. Great instructions there. Honestly, as IceAge says, it's really not that hard. But it does take practice.

garlic08
05-17-2010, 13:48
I've hiked those trails you mentioned, and throw in the Arizona Trail, without GPS. I know how to use a GPS and I like the technology, but I choose not to carry one when I hike.

I've been picking up lessons in route finding my whole life, from navigating while Dad drove, to Boy Scouts, to bicycling my way around a major city as a kid, to increasingly difficult hiking, and most recently a 10-year career in wildland firefighting in Colorado (heavy GPS use there). Before that I had a career as a design engineer and I worked with land surveyors, too--the people who make the maps. So it'll be hard for me to tell you how to learn it. It's been a life-long process for me. It's become second nature, so I don't even think about it.

One tip I learned on the lesser-known Western trails is rely heavily on my watch. I set the hourly chime as a reminder to mark my best estimated position on my map in pen. That way I have my progress plotted, I make sure I'm still on my intended route, I have a good idea of my hiking pace so I can extrapolate where I'll be in the next hour or at the end of the day, etc. Knowing your pace in various conditions will also allow you to time your hike to a known critical point where you need to make a decision. If you know it's 1.3 miles to faint trail junction that might not be signed, and you know your pace is 2 minutes per 0.1 mile (3 mph), set your watch alarm for 26 minutes. It's amazing how well that works. I use my watch sometimes more than my compass.

I guess you want to start simple and find out what "tricks" work for you. You can probably find more than you need to know in books at outfitters and on the Web.

Mags
05-17-2010, 13:49
For those that have hiked the CDT, PNT, or even the PCT, how/where/when did you learn your map, compass, GPS, and orienteering skills?

I took a class with the local chapter of the Rhode Island AMC. Two two-hour sessions of classroom work and one morning of field exercises. I learned with 7.5" maps...and 10' contour lines! :) The basics, however, did not change.

As for GPS, self taught. If you can count to ten..you can use UTM.

Many local outing clubs, REIs, etc. will offer free or inexpensive classes.

Once you learn? Go out an practice! If I can learn in the second most densely populated state...anyone can learn. :D


I found these sites helpful for map,compass and GPS use:
http://www.learn-orienteering.org/old/
http://www.gpsnuts.com/myGPS/GPS/Tutorials/Maps/maps.htm



Would you say that orienteering is different in the eastern forests vs. the wide open west?

Heck yeah. In CO, I can often just eyeball where I am going and take if from there (wide open spaces) vs. the deep woods of say Maine.

Of course, Eastern 'wilderness' areas tend to have a good network of trails to get places. Off-trail hiking in CO is more feasible and needed at times.

Of course, in places like being above canyon in Utah, there is sometimes a tad too much open space! :)




I mean, isn't part of the day spent being misplaced and trying to calculate where to go and where you are?

Yep..but only if I am not paying attention. If I daydreamed (which I did) I often zigged where I should have zagged on the CDT!



Also, it is feasible to find your way in an isolated area with only a map and compass?

I did the CDT without a GPS fwiw.


A GPS can be helpful and it is probably a good skill to learn..but they are easy to use. UTM coords are on base-10 and broken into centimeter grids. Easy-peasy/Mac-n-cheesy!


It's amazing how well that works. I use my watch sometimes more than my compass.


Ditto! Dead-reckoning is often very useful.

vamelungeon
05-17-2010, 13:52
A good way to practice using your GPS is geocaching.
I have a book here called "Be Expert With Map and Compass" that is very good, maybe a little more detailed than you might want.

Pedaling Fool
05-17-2010, 14:16
I havenít walked out west yet, but Iíve done a lot of bushwacking.

It is easier than you would think. But then again of all the bushwacking and off-trail hiking Iíve done, using a map and compass to find the AT or a road or a town. Iím sure there are those that could find a smaller target, but thus far Iíve not had to develop those skills. In other words, when Iím trying to get back on the AT I know itís either east/west of my position and I just have to walk in that direction, now to find a particular point on the AT, well thatís another problem.

I often inadvertently walk off the AT, this is kind of common for me:o so Iíve learned that itís easier to use my map and compass to relocate the trail. I've bushwacked in every state along the AT, except Georgia and W. Virginia.

In Penn I ended up in an old farm field with a dilapidated house next to a road, luckily I found the name of the road on my map. However, (and this is a problem I have with many AT maps) the direction I had to go went off the map, so I used a little imagination in what I thought the road would do combined with the fact that the AT is an unbroken line north to south, therefore I should eventually run into it. I eventually did and yes I yellow-blazed.

It really does help to know you pace and keep an eye on the compass, your watch and the lay of the land/landmarks. Also keep checking back with the map, itís easy to make a mistake with just one look at the map and relying solely on your compass/watch after that.

It is a little scary at first not being able to rely on markers/blazes, but you get use to it with time.

Dogwood
05-17-2010, 15:04
I don't consider myself an expert land navigator or orienteering wizard, but like you, when I knew I wanted to start taking on lesser used more remote hikes sometimes without established tread or bushwacking routes I also knew I had to become proficient at land navigation. You probably have looked at maps before and already know some things about them, like how to identify lakes, rivers, mountains, ridges, roads, forested areas, depicted trails etc., read topographical contour lines signifying elevations and grade, scale, and find magnetic and true north, etc. It sounds like you already know some of the very basics about compasses. That's where I started from too.

I took two 4 hr classes at REI on Basic Land Navigation. The first one was very basic; although a beginner's class, I learned some things that I assumed I already knew. The second class was somewhat more advanced. It was good because it included a short field trip which allowed more hands on experience by putting into practice many of the things I learned in the beginner class. I think the teacher was very good at relating the material too. For REI members the cost is minimal, IMO, like $20. REI also holds beginner and more advanced classes on GPS navigation. Later, I took a wk long survivalist's class, learned some additional land navigational techniques, and put into greater practice what I already knew. Like most things the more you practice at it the better you get. Although, it's not absolutely necessary for you to take a class to be able to land navigate safely, especially on the trails you mentioned, I find it helps grasping the subject, especially if you are a raw beginner, if you are able to ask questions in person and have hands on demonstrations and explanations in person. It's not all that hard.

If you seek a thin rudimentary beginner's type book with large print and color prints that aid in understanding land naviagation the Falcon guide "Map and Compass" might prove useful to you. Putting into practice what is in this book probably is all you need to navigate safely on the trails you mentioned during typical thru-hiker season.

A handy practical decent for field use as a beginner pocket size book(smaller and fewer pics and smaller print) by Cicerone Publications titled "Navigation" written by Peter Hawkins which includes one short chapter on GPS, is also available. What I find nice about this handy little light wt guide is that it is weather resistent.

If you want a smallish sized slightly more advanced, with two chapters on GPS, but without the color pics(just black and whites) and not weather resistant you might want to look at "Land Navigation Handbook" written by W.S. Kals.

bdpalace
05-17-2010, 15:45
Free and proven effective:

http://www.globalsecurity.org/military/library/policy/army/fm/3-25-26/index.html

safn1949
05-17-2010, 16:25
Free and proven effective:

http://www.globalsecurity.org/military/library/policy/army/fm/3-25-26/index.html


Excellent,that's what I tried to tell someone else in another thread.That the Army has been doing the old fashioned way for a long time.They said you couldn't find where you were with a map & compass with any precision.Uh huh.:D

Marvin
05-17-2010, 18:01
I really hate the thought of buying and even learning how to use a GPS.


Tilly, using a GPS may seem intimidating to you if you've never used one, but in reality it is very easy, just as Mags said above. However, if you take the time and effort to learn the old fashioned map and compass, you will be in much better shape when the battery of your GPS gets discharged, or the unit fails for some other reason. You will also have much more fun during your hikes.

rhjanes
05-18-2010, 10:00
Hook up with a local orienteering club. They will be happy to show you the basics all the way to advanced. Then attend some of their meets. Start on "white", or "yellow" course level. Move to harder courses as you feel comfortable.

Here's one in Indiana.
http://www.indyo.org/

Heres USOF.
http://www.us.orienteering.org/

Just Jeff
05-18-2010, 10:25
I think teaching yourself orienteering from a book would be much more time-consuming than taking a class. I learned from several military schools, and it's really pretty easy when put into practice...but pretty difficult to explain in writing in a way that's intuitive. So I'd recommend getting a book or two, but only to supplement a couple of classes at REI or a local hiking club. You could probably find a Boy Scout who could do it as a community service requirement or something.

Orienteering is pretty fun, but it's even more effective when you really know how to read the map and can do terrain nav w/o the compass. The west has a lot of open terrain with readily identifiable landmarks like big peaks; it's pretty easy to keep your position once you know it (but you still have to pay attention or you'll become "unfound.") In the heavily forested east, you need a better feel for terrain nav b/c you can't always find your location just by looking at that big mountain to the west, and a lot of the trails aren't on the maps.

LIhikers
05-18-2010, 11:08
A very good way to learn these skills is to join a local orienteering club. Members will be able to give you personal help, if they don't have classes. Then try one of the orienteering meets, at the easiest level. Then it's a matter of practice makes perfect.

Here's a basic explanation http://www.thecompassstore.com/howtousemapa.html

Tilly
05-18-2010, 11:09
Thanks everybody for taking the time to respond to this thread. I've gotten alot of ideas and the whole subject seems a little less intimidating.

Rocket Jones
05-18-2010, 11:26
I know the Prince William National Forest has several orienteering routes set up for visitors to use. You can ask at their Ranger station for more information.

Might be worth checking with state or national parks near you.

beakerman
05-18-2010, 11:47
I teach orienteering for my troop and do our orienteering events for our district. I learned my skills in the scouts many moons ago. You can always ask one of your local troops to give you a hand with at least the basics. They may not be able to handle declination because on proper orienteering maps declination has already been taken into account, but they can certainly get you started. I would suggest though that if you are looking for the scouts to do a good turn for you yo umight want to consider doing one for them and ask for an even trade..consider teaching a merit badge course based on your skills. Ask and they will help you figure out what you can do. Everyone has a specialty, hobby or interest that they can do.

Also look into your local orienteering clubs. Don't laugh I didn't know it until about two years ago but Houston TX has one and we aren't known for our topography down here.

rhjanes
05-18-2010, 12:33
I teach orienteering for my troop and do our orienteering events for our district. I learned my skills in the scouts many moons ago. You can always ask one of your local troops to give you a hand with at least the basics. They may not be able to handle declination because on proper orienteering maps declination has already been taken into account, but they can certainly get you started. I would suggest though that if you are looking for the scouts to do a good turn for you yo umight want to consider doing one for them and ask for an even trade..consider teaching a merit badge course based on your skills. Ask and they will help you figure out what you can do. Everyone has a specialty, hobby or interest that they can do.

Also look into your local orienteering clubs. Don't laugh I didn't know it until about two years ago but Houston TX has one and we aren't known for our topography down here.Yep, that would be "HOC". There is also a club in LA and here in Dallas area we have NTOA (North Texas Orienteering Association), we do about 9 meets a year (during the school year). At every meet Ralph Cortney teaches several beginner classes on it. If you get the boy scout orienteering handbook, Ralph literally "wrote the book" on it. But he will make you feel just like a friend within a few minutes of meeting him.

JAK
05-18-2010, 14:21
Those orienteering maps are pretty wild looking. Seems like an art in itself, somewhat separate from or in addition to regular map work. A sport I would like to try some day.

I've done alot of sailing and chart work, but still get lost in the woods. I am also a natural whiz and math and geometry, but still get lost. I also took map work during my basic training, but still get lost. In the process I have gotten rather good at bushwacking and map and compass work. So there is your answer. Now if you aren't as trained or qualified as myself, you might not need to get lost so often as me in order to become such an expert. Just saying it worked for me, and continues to serve me well.

beakerman
05-18-2010, 15:22
Those orienteering maps are pretty wild looking. Seems like an art in itself, somewhat separate from or in addition to regular map work. A sport I would like to try some day.

I've done alot of sailing and chart work, but still get lost in the woods. I am also a natural whiz and math and geometry, but still get lost. I also took map work during my basic training, but still get lost. In the process I have gotten rather good at bushwacking and map and compass work. So there is your answer. Now if you aren't as trained or qualified as myself, you might not need to get lost so often as me in order to become such an expert. Just saying it worked for me, and continues to serve me well.


Like I said those orienteering maps already have the declination taken into account and there are as I understand it a few ways to do that. One is to "regrid" the map (basically amkethe map point to magnetic north rather than dtrue north or grid north (which are not the same thing depending on where you are on your projection grid) the other is to do all the math ahead of time so the course runners do not have to do it on the fly. that is the method I am used to but I have seen maps that have been re-oriented and they aren't that bad.

SunnyWalker
05-18-2010, 17:55
Tilly, it's easy to use map and compass. Get the book or take the class. GPS can be good, but I'd advise not to use it alone. One other factor: weight of GPS can be significant. And then there is the constant battery factor. I wanted to carry something else instead of the GPS so I chose to not carry and use it for backpacking. You hold a compass in one hand, and GPS in other with batts. You'll see.
But also-if you are going to be on an established known trail you certainly could get by without GPS and perhaps without map and compass! The AT would be an example. The CDT-you'd need map and compass at the least. When I speak of maps I mean topographical maps. Compass would be a Brunton or Silva liquid filled compass.

rhjanes
05-19-2010, 10:09
Orienteering maps are incredibly detailed. The beginner level courses are usually easy (on trail) or use things like power lines, pipelines and fences to navigate.
There are two things to focus on with orienteering and bring forward into any "woods" activity.
One is the map to compass and how to use them together.
The second is reading the map for land features and following those. Sometimes orienteers will attempt a course and NOT use the compass. They read the land features. Quite handy when following a trail. "follow the trail until the second bend. Cross the stream on the left when the trail breaks to the right. go 20 paces and intersect a fence. Follow the fence to the right until it takes a 90 degree bend. Pick up the powerline and follow it." Really helpful in following trails, rivers, etc.

LIhikers
05-19-2010, 17:35
Check http://www.indyo.org/ for an orienteering club in Indiana

fiddlehead
05-19-2010, 20:41
Tilly, using a GPS may seem intimidating to you if you've never used one, but in reality it is very easy, just as Mags said above. However, if you take the time and effort to learn the old fashioned map and compass, you will be in much better shape when the battery of your GPS gets discharged, or the unit fails for some other reason. You will also have much more fun during your hikes.

And on the other hand, when it's foggy, drizzling, and you are totally lost, and just wish you could figure out where you are on your map, that's when it's not so easy out there.
Don't discount the importance of a GPS on trails where there often is not a trail.
I bushwhack more than most and find the GPS the most important tool in my pack sometimes.

I now even prefer to hike without a trail. (except when I'm invading a monkey's space)

Dogwood
05-19-2010, 21:29
And on the other hand, when it's foggy, drizzling, and you are totally lost, and just wish you could figure out where you are on your map, that's when it's not so easy out there.
Don't discount the importance of a GPS on trails where there often is not a trail.
I bushwhack more than most and find the GPS the most important tool in my pack sometimes.

While there are times when I would rather have a GPS folks have been "eventually" finding there way out there long before they were around. They are just another heplful tool to route finding, as long as you know how to use them. Same with a compass! I will say though, at times when I possessed quite detailed accurate maps and compass, and they eventually assisted me finding my way, after getting lost, there were times when I wish I had a GPS, like when I was lost in the bottom of a remote canyon system in Utah, bushwaking/hiking in dense Hawaiian forest with less than 30 ft visibility and no way to climb a tree to find any identifiable features from my maps, or hiking off trail in dense fog in Vermont with less than 10 ft visibility, or continuing to hike in heavy snowfall with less than 20 ft visibility in Colorado, or any of the hikes I've done in Texas, Arizona, Utah, or S. California where there are no distinguishable map features in view other than 20 ft elevation changes, or while kayaking in the Everglades No fences, no mountains, no rivers, no roads, no cliffs, no major identifiable elev changes just a compass telling me that if I headed "that" direction for 20, 30, 40 miles I would eventually come across something I could recognize from my maps.

Connie
05-25-2010, 13:19
I use a Silva wrist compass with a sighting slot, so I don't have to fumble around.

I also use a GPS, and I mark difficult parts of a trail (steep dropoff, like that) as waypoints, so if I have to back in a hurry, including in a hurry at night or in fog, I have the difficult parts of the trail marked.

If too dangerous, I go to Plan B: "stay put, Bivouac". Maybe radio for assistance. I haven't had to do that.

+1 for orienteering training, but the club may be about speed events. Get the usual training, including practice in the field with supervision.

Especially, ask for help to find your position where you are. I use an altimeter to help in fog, when I was using only map and compass. Now I use all three: map, compass, and gps (includes altimeter).

I find the most useful help to know where you are is to be observant, and to turn and look at where I came in the woods or where there are features if in the open, maybe mountains right side, road left side, lake that way, for example, and then more detail. Of course, looking at a map and checking where you are, at times, helps.

Seriously, if you see a trail sign in the CDT don't necessarily believe it. Strawberry Crk Tr. has five or six signs altogether, with only one pointing in the right direction. There is nothing on the CDT "trail" like the signage, or the maintained signage, on the AT. Really.

I have some helpful information on my orienteering (http://www.ultralightbackpackingonline.info/orienteering1.html) page.

crazyonelost
05-29-2010, 08:04
I know I am not the great map reader/compass user,but again i usually stay on well marked blazed trails. I usually use them when hiking to figure out my spot on the map to the location I am at .

I have a gps but I found out that deep canyons/tree cover/weather effects it alot and sometimes no signal at all. I usually use the gps to see how far to the next waypoint in general and when I am home download the trail route to my topomap program and see how the trail ran and store it for later use. I also use the speed and time to see what my general pace overall was.

The Old Fhart
05-29-2010, 09:21
I am surprised that only poster, Connie, 2 post back, mentioned using an altimeter. An altimeter is one of the simplest tools you can add to map and compass that will greatly enhance your ability to locate your position. For the last 25 years or so I have used various Casio watches with altimeter. If you have a map and aren't hiking on a flat trail, an altimeter can help pinpoint your location. If you wear a watch anyway, like I do, getting one with an altimeter feature adds no extra weight. The current Casio watch I use is model PAW-1300 which has temp/compass/barometer/altimeter built in. For techo-geeks, here is a youtube video review of the watch (http://www.youtube.com/watch?v=e5GTjn-mkYM). Although this watch is high end and a little expensive, basic watches with just an altimeter feature aren't that expensive. Well worth looking into.

Pedaling Fool
05-29-2010, 11:26
I've never used an altimeter, but I can see the advantage of one, provided that you calibrate at every opportunity when youíre at a known elevation. And you must also be mindful that if you go to sleep at a known elevation Ė verified that night Ė it may be different the next morning, due to weather conditions. So itís very important to check it before you leave camp. In short, you got to keep track of it. But, in all fairness you got to keep track of magnetic declination as well when using a compass.

Of course this doesnít apply to GPS altimeters.

crazyonelost
05-29-2010, 12:52
On my trip last week Laurel Highland trail. My partner and I had 2 diff gps units and there were at least 500 ft difference of elevation between the units.

Sly
05-29-2010, 14:45
Looked online and fudged it. Half the fun is not knowing exactly where you are. The other half is finding yourself.

weary
05-29-2010, 15:12
Tilly, using a GPS may seem intimidating to you if you've never used one, but in reality it is very easy, just as Mags said above. However, if you take the time and effort to learn the old fashioned map and compass, you will be in much better shape when the battery of your GPS gets discharged, or the unit fails for some other reason. You will also have much more fun during your hikes.
I agree. Learning to use a simple GPS is easy. As easy as using a simple point and shoot camera. The key words are simple. Sophisticated GPS, like sophisticated point and shoot cameras, have complications that only a bit of study and a lot of practice enables one to be proficient.

My Delorme PN 40 has multiple menus and multiple pages. Each simple in themselves. But putting it all together takes more effort than I've devoted to it so far. Same with my sophisticated point and shoot camera. So on both I've only learned as much as I've needed to know at the moment -- something like my computers, despite almost two decades of using the things. I've learned to make my GPS create a track and how to transfer that track to a map that anyone with a simple compass can use.

But to get to the point of this thread. People have been finding their way in the woods for millennia with crude maps and compasses. I can attest that using a GPS makes it easy to map a trail you have created. It does nothing else that I have found I need to know, at least so far.

Weary

Shutterbug
05-29-2010, 16:12
IAlso, it is feasible to find your way in an isolated area with only a map and compass?

I learned basic navigation skills from my father. He never used any insturment -- not even a compass. I use a compass or gps to confirm my navigation, but basically rely on my instinct.

My father and I fished large lakes in Arkansas and Louisiana. After a long day of fishing, he could always go directly back to the boat dock without a map, a compass or a gps. His tips were:

1. Pay attention to landmarks.
2. Be aware of the direction by watching the sun.
3. Stay oriented at all times. If you wait until you are lost to determine directions, it won't really help you. You need to know in what direction you have gone to know what direction to return.
4. Pay attention to wind direction.
5. What they tought us in scouts about moss growing only on the north side of the tree isn't true but one can confirm directions by observing the local moss patterns.
6. Listen -- your ears can help you stay oriented. Notice the sounds you hear on your way out. They can help guide you on the way back. I have been on a lake when the fog rolled in. If it hadn't been for the sound of the train in the distance, I might still be out there.

So, to answer your question, it is very feasible to find your way in an isolated area with nothing more than a map and a compass.

The Old Fhart
05-29-2010, 18:08
crazyonelost-"On my trip last week Laurel Highland trail. My partner and I had 2 diff gps units and there were at least 500 ft difference of elevation between the units."WARNING-technical explanation follows.

the elevation a GPS displays isn't commonly understood. While a minimum of 3 satellites is needed for location, a minimum of 4 are needed for elevation. Signal strength and satellite geometry play a big part in elevation readings (http://docs.controlvision.com/pages/gps_altimetry.php). What makes matters worse is the elevation displayed on a GPS isn't the elevation above MSL (mean sea level) like a barometric based altimeter, but above a model of the earth which isn't exact. If you check out this NOAA reference (http://www.ngs.noaa.gov/PUBS_LIB/gislis96.html) it will state that if taken carefully, the GPS elevations could be about 175 feet off because the model of our earth isn't exact. The roatation of the earth causes it to 'bulge' in certain areas so it isn't an exact sphere. Elevation readings on maps have been taken by barometric based altimeters and when set recently at a known reference point, are generally quite accurate, generally within a very few feet.

NOAA-"The Global Positioning System (GPS) is commonly considered a three-dimensional system. But, the heights obtained from GPS are typically heights above an ellipsoidal model of the Earth. These GPS ellipsoidal heights are not consistent with leveled heights above mean sea level, often known as orthometric height. The conversion from ellipsoid to orthometric height requires a geoid height model. Geoid heights in the conterminous United States range from about -8 meters to -53 meters, and display considerable variation in the mountains. Through the use of careful GPS survey procedures coupled with high-resolution geoid models, surveyors have obtained orthometric heights with an accuracy commensurate with that of leveling."

Pedaling Fool
05-30-2010, 08:39
WARNING-technical explanation follows.

the elevation a GPS displays isn't commonly understood. While a minimum of 3 satellites is needed for location, a minimum of 4 are needed for elevation. Signal strength and satellite geometry play a big part in elevation readings (http://docs.controlvision.com/pages/gps_altimetry.php). What makes matters worse is the elevation displayed on a GPS isn't the elevation above MSL (mean sea level) like a barometric based altimeter, but above a model of the earth which isn't exact. If you check out this NOAA reference (http://www.ngs.noaa.gov/PUBS_LIB/gislis96.html) it will state that if taken carefully, the GPS elevations could be about 175 feet off because the model of our earth isn't exact. The roatation of the earth causes it to 'bulge' in certain areas so it isn't an exact sphere. Elevation readings on maps have been taken by barometric based altimeters and when set recently at a known reference point, are generally quite accurate, generally within a very few feet.
Interesting, I did not know that.

camperpat
05-30-2010, 19:01
I joined an orienteering club, they are all over the country. It's a fun way to learn map and compass skills. I belong to Delaware Valley Orienteering Club, their web site has a link for other clubs in the USA Camperpat

crazyonelost
05-31-2010, 08:08
I still can't figure out the exact lat/long on a certain point on a map.but everything else I have a decent idea of reading it. I usually don't pay attention since my gps does it for me automatically.Great tool when using for search and rescue and injuries way off roads to help in emergency call for help to find you.