Edmonds orienteering course points the way
Too bad the $100 GPS, or Global Positioning System, device couldn't function in the middle of Edmonds.
Although he was teaching how to navigate the old-fashioned way, with a map and compass, Ranger Owen Caddy brought along his Garmin eTrex when he herded a recent class into the Yost Memorial Park woods.
"A lot of armchair adventurers think, 'Ah, I can buy a GPS unit, and I won't have to worry about maps and compasses,' " said Caddy, an interpretive specialist for Edmonds. "And I'm here to tell you, that will get you in a lot of trouble."
Sure enough, as the group wended along trails through a forest of alders and huckleberry bushes, the GPS unit became useless in some spots. The devices must receive signals from at least four satellites to pinpoint locations, he said.
"A compass will work wherever you go," said Caddy, a former mapmaker. "This is what will help you get out of trouble — a good compass."
Edmonds holds its annual orienteering classes in the fall as a service for hunters, who are more prone than hikers to stray from trails. Last year, several hunters, some accompanied by young sons, turned out for Caddy's class.
This year, however, he attracted a purely hiking crowd. Six students — a father and son plus four women — signed up to learn Caddy's art.
"I do a lot of backpacking, and I also sail," said Star Conrad of Lynnwood, who has three teenage sons. "We don't necessarily go off-trail, but knowing more about it would be nice."
Caddy began with the basics: Compasses don't point to the North Pole. They instead point to magnetic north, which has shifted hundreds of miles over the past few centuries.
In Snohomish County, for instance, compasses point to a spot about 18 to 20 degrees east of the North Pole. But in Minnesota and Wisconsin, compasses are essentially accurate — for now, anyway.
"The Earth is essentially a great big magnet," Caddy explained.
As the planet spins, its molten iron core shifts, causing its magnetic field to fluctuate. The needle of a compass is magnetized, so its tip seeks the north-flowing lines of magnetic force.
Good maps include the magnetic declination, the number of degrees separating magnetic north and the North Pole. Adventurers who rely on maps and compasses should make sure they have current declination data, he said, because it can change in just a few years.
Once his students understood the basics of declination, he took them outside for a hands-on demonstration of forces that can reduce a compass' accuracy. Car keys, glasses, umbrellas and metal clips on backpacks can confuse the needle's magnetic impulses. So can chain-link fences or large rocks containing iron or magnetite.
Most pieces of jewelry, including silver and gold rings, have no effect.
For the group's first real exercise, Caddy offered a series of specific magnetic compass bearings that led them, step by step, in a broad loop around the Yost pool buildings.
If the bearing was 290 degrees, for instance, class members would orient themselves to magnetic north, determine which direction was 290 degrees and then walk toward that spot. If correct, they found an orange plastic ribbon tied to an object in their path.
"How are you doing? Is this all making sense?" Caddy asked, as the group stood on a grassy hill above the Yost pool, on the edge of a stand of trees.
"I've learned an enormous amount of stuff already," said Janet Elene, a substitute teacher from Edmonds.
After another lesson, this time on the origins of latitude and longitude and how contour lines on maps depict the steepness of slopes, the class hit the Yost trail system.
Equipped with compasses and park trail maps, the students headed down Sword Fern Trail. The map's depth of detail, showing boardwalks and stream crossings, made it ideal for compass work.
When hikers reach an identifiable spot, such as a bridge, they can easily orient themselves and take magnetic bearings to determine which direction to take to reach a specific goal, Caddy explained.
Caddy showed his students how to find their physical location on the map, then place their compasses directly on that spot.
Next they adjusted their compasses so the magnetic needles pointed in the same direction as the north declination on the map. Once they had their bearing, they could pick any spot on the map and figure out which way to go to find it.
From one trail landmark, the class could tell the pool must lie at 120 degrees. In a true, off-trail orienteering situation, a hiker would face that direction, find a landmark and head for it. Once there, the hiker would find another landmark at 120 degrees and continue in the same manner to the pool.
Caddy cautioned his students to keep careful notes in case they make a mistake and must retrace their steps.
"What happens if you're in the mountains and you take a bearing from a (specific) mountain, and it's the wrong mountain? If it's an unknown point, then you're in trouble because it's just a fantasy."
At the end of the four-hour class, Elene was pleased.
"I've always been leery about getting off the trail because I'm not very good about directions," she said. "I would feel confident now about leaving the trail. But I'll definitely practice it first."
Diane Brooks: 425-745-7802 or dbrooks@seattletimes.com
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