Navigation Thread

[Shnick]

Great thread, Shnick. I'll give a +1 to Kellstrom's book as well. Most compass and orienteering folk I know wax poetic about the book .... and it was a useful primer for me as well.

A good addition to this thread would be smartphone navigation apps (for iPhone and Droid). I wish I had the time to go into detail about my fave iPhone apps. But that will have to wait for another day.

Thanks! I'm on it...
Trimble Outdoors and Backpacker magazine have a Partner App that can track your movements, take photos and movies along the trail, and upload it to the Trimble site in one package. You can also download other peoples trips and follow in their footsteps.

Check it out here: Backpacker GPS Trails

Edit:
Here is one of my past hikes in at the Rock Hawk Effigy Trails near Eatonton Ga.

[Pawoodsman]

I just need to get out and practice more, Got lazy hiking designated trails

[Shnick]

A quick note on how to reverse your course using a "Back Azimuth".
We often have to reverse course to backtrack to a landmark or find a spot we've already passed.

An "Azimuth" is just a direction from where you are. Nothing more.

Let's say Keyser Soze is hiking to his favorite fishing spot at an azimuth of 293° (Northwest)
Oh no! He forgot his tackle box...
Will our fearless hero get back to the truck to get his fishing kit? How will he do it?

Simple. He subtracts 180° from his current heading (azimuth) of 293°. We get 113°.
So he sets his compass and heads back to the truck.

Some hours later he catches his fish...

and bids it a fond farewell...


NOTE: If your current heading is less than 180, then add. if it's more than 180, subtract.
This will keep you mathematically between 0° and 360°.

Up next, Identifying Topo Relief Features

[Shnick]

Topo maps can get cluttered, especially the 1:250K maps.
Those wiggly lines on your map indicate the contours of the terrain area around you as well as altitudes, normally measured in feet above Sea Level.

When we look at a map we can see obvious features like highways, lakes and cities, but in the remote areas we may not be able to reference these points. Hills, ridges, cliffs, valleys and spurs can help us in figuring out where we are, and more importantly, how far we are from our objective.

Hill: The most common feature on our map, a hill has a distinct set of concentric rings and will have the highest altitude labeled on the top most ring.
As with all contour lines, the closer they are together on the map the steeper the terrain.


Cliff: A cliff is one of those things you would like to see on a map BEFORE you walk over it.
Very narrowly-spaced or converging lines will show where cliffs are. Look at the ground, not the map.


Depression: A depression is a shallow dent in the ground, sometimes caused by a dried up lakebed or a limestone sinkhole.


Ridge: The ridgeline is the easiest way to walk and still keep an eye on the valleys below. If you follow a ridgeline, you'll easily find your way. It's normally indicated by a dashed line. - Example: The Continental Divide


Spurs: No, not the San Antonio Spurs, these are left over from erosion. They often extend from the ridge all the way down to the valley floor.

[Shnick]

Valley A valley is the concave or inner area between spurs. This is where gold prospectors would concentrate their digging.


Saddle: This is the area between two neighboring hills. An hourglass design will indicate this on a map.


Draws: These have steeper sides than valleys, but are still caused by water runoff or heavy erosion.


Cut/Fill: Railroads or highways are sometimes cut or filled into the terrain to make ascending and descending easier.
This is indicated on the map as a series of hashed lines parallel to a road or railway.


Quiz: Match the following terrain features to the patterns on the map.

Cut
Fill
Depression
Ridge
Hill
Saddle
Cliff
Spur
Valley
Draw

[riverjoe]

Great stuff Snick . We used to call spurs fingers . Back in 1968 when I read a map in the mountains all of the time I usually used an azimuth to prove what I thought was true , really was true . ie "I think Im on this mountain , but if I was ,that spur , draw , saddle would be at such and such degrees ."
If I don't prove this is the mountain Im on then I might call an air strike on my own mountain instead of the one I think the enemy is on . Delta Co. 2/327 101st Airborne . This was our sister company and I witnessed that air strike back in 68 .

Sometimes I feel like John Goodmans character in that movie " The Big Lebowsky " . Remember everything he said or did was related to the NAM .

[Keyser Söze]

An "Azimuth" is just a direction from where you are. Nothing more.

Let's say Keyser Soze is hiking to his favorite fishing spot at an azimuth of 293° (Northwest)
Oh no! He forgot his tackle box...
Will our fearless hero get back to the truck to get his fishing kit? How will he do it?

Simple. He subtracts 180° from his current heading (azimuth) of 293°. We get 113°.
So he sets his compass and heads back to the truck.

Some hours later he catches his fish...

and bids it a fond farewell...


NOTE: If your current heading is less than 180, then add. if it's more than 180, subtract.
This will keep you mathematically between 0° and 360°.

Up next, Identifying Topo Relief Features

nahhh i just drop bread crumbs like Hansel und Gretel

[TheProfessor]

With all the recent interest in land navigation, and all of the other great posts in this thread, I decided to get out in the woods, practice the skills and video them. The result was pretty horrible: The video ran too long, the narration was rambling and disjointed ( so what's different? ) and the camera work was poor, because I did it myself. I zoomed out when I meant to zoom in, and panned waaay too fast so viewers would feel seasick. While zoomed in all the way, I got lost and couldn't find my objective on the map, even though it was only two inches away!

After wading through the entire recording this morning, I decided to scrap it and try again. The usual disclaimers will apply to this new series:

I am not a professional navigator, nor do I claim to be. This series will be about how I approach land navigation problems; I am not telling you how you should do it. My formal training in land navigation consists of reading Kjellstrom's book, and studying the one-page brochure that came with the Silva Polaris compass I bought 25 years ago.

On the positive side, I have taught vector analysis, English-metric conversions, ratio and proportion and trigonometry to high school and college students for more than a generation; and what's more I just got this new document camera and screen-recording software and wanted an excuse to try it out!


The series is in five parts:


1. Planning my trip using USGS topographic maps, Google Earth images and photocopied enlargements of portions of the topos.


2. Pace counting and pacing beads


3. Managing map scales and unit conversions.


4. Converting the trip plan into a series of displacement vectors.


5. Taking the hike and practicing the skills.


If I can salvage enough content from yesterday to make video #5, ok; if not, I'll make the trip again, and coerce Mary Ann to come along as videographer next time!

Here's video #1: Let's talk about how you approach trip planning.

[TheProfessor]

In this segment, I calibrated my "backwoods odometer" by pace counting. First, I measured off 100 meters (328 feet) and set a flag at each end for reference. I have successfully used chalk marks on a sidewalk to accomplish the same purpose. For the video, I used a 100 foot tape measure; but at other times I used a measuring wheel borrowed from the college maintenance staff.

Walking consistently is the key to accurate outdoor measurements. I walked the 100-meter course several times, counting paces, or "double steps" as I went. Doing this repeatedly yielded an average of 62 paces for the 100-meter distance. Walking uphill and down, through snow or across rough ground will likely affect this count somewhat, but errors of less than 5% are pretty normal.

For measuring distances more than 100 meters, pace beads are a convenient way to keep track of the distance covered. Essentially an abacus-on-a-string, the typical set has 2 groups of beads: nine on one side of a knot, and 4 on the other. Moving one bead of the nine to the knot would represent 100 meters, two for two hundred and so on. When 1000 meters has been covered, I would slide the nine beads back to their original position, and slide one bead of the group of four to the knot to indicate that distance: 1 kilometer.

[riverjoe]

There is a little book I like a lot thats sort of simplistic and probabley geared toward teenagers but it has some nifty little tips I think . One of these is this distance wheel that clicks on every revolution that author uses to make maps of his AO .

Another is knowing the prevailing winds in your intended hiking area . For instance around here 90 per cent of the time the wind is westerly maybe north westerly , maybe south westerly but always west .
This would be useful only when compileing information to determine your direction .
From the book " Cache Lake Country "