Who Needs a Map and a Compass?

Navigation on the Appalachian Trail is an interesting discipline. On the one hand, it's as basic as following the white blazes that are painted on trees, rocks, fence posts, and signs, marking the way north (or south). It's like following Hansel and Gretel's trail of white pebbles. Simple, functional, and you don't even need a "White Blazes for Dummies" handbook. It just makes sense.

The white blazes make map and compass work entirely peripheral to the hiking experience, to the point where the map and compass just add unnecessary weight to an already burdened pack. In this way a data book, with mileages between water sources, shelters, peaks, roads, towns, etc., is much more useful. This is the resource that I carry, and it's worth its weight in gold.

If you dig a little deeper, the navigation question becomes more complicated. For example, let's take a look at the question, "Which way is north?" You could be talking about "AT north," which, if you're hiking from Georgia to Maine, is whatever direction your facing while hiking. Data books rely heavily on AT north, referencing objects as west or east of the trail, when really they mean left or right.

You could also be talking about true north. As you stand on the trail, this would be the direction you would have to face in order to be looking at the North Pole. If you've ever used a road atlas, these maps are oriented with the top of the map pointed toward true north. Again, pretty simple.

Finally, you could be talking about magnetic north. If you did take the extra weight of a compass during your AT hike, this is the direction the compass needle would point. But isn't that the same as true north? It depends on where you are, and on the Appalachian Trail that is never true because magnetic declination comes into play. Declination is the angle, measured in degrees, between magnetic north and true north. In general for 2011, the Mississippi river draws a north-south line across the US where magnetic and true north are close to the same. As you head east toward the Appalachians, the compass needle is "pulled" back west toward the Mississippi; the further east you go, the further the needle is pulled. At the southern end of the trail the compass needle is pulled counter-clockwise about 5 degrees; at the north end, declination grows to 15 degrees or more. So, while on the Appalachian Trail, to calculate true north you have to "add back" the declination to the compass reading to get true north. In other words, you are theoretically moving the compass needle clockwise the amount that it has been pulled counter-clockwise (or west) by declination. Make sense? If you're still confused, believe me, you're not the only one -- and I haven't even mentioned yet what happens when you head west of the Mississippi instead of east toward the AT, or how declination changes over time, but that's for another post.

All of that to say, on the AT I've found that it's more interesting to know where you're headed by sight, not by any of the three meanings of north. Yes, sighting the white blazes is part of what I mean, but there's also another meaning that is a bit more subtle and requires some practice. When I'm standing on a peak, I first enjoy the view. Then I'll look in the general direction of "AT north" and try and spot the next prominent mountaintop. Nine times out of ten, this is where I'm headed next. What if that next bald is some distance away? Usually, I'll just use line of sight to connect the summit I'm on to the one in the distance by a ridge line or gap that connects them; and if not a ridge, I'll visually connect the knobs that stand in between like a simple game of connect the dots. It's amazing how with a little experience, this method of navigation is fairly reliable, made possible by the fact that the AT loves to visit the vistas and other high points of the mountains along its course.

So how would you navigate the AT? Visual anticipation? A map and compass? Just a data book? Nothing at all? You'll find all of these types of hikers if you spend enough time on the trail.