The Iditarod Trail Committee claims 1,149 miles on both its northern and southern routes -- an effort to ensure the distance includes 49 (for the 49th state) and exceeds the 1,000-mile Yukon Quest International Sled Dog Race between Whitehorse and Fairbanks.

GPS tracking devices, on the other hand, show you the northern route trail -- the one mushers are on this year -- is just over 900 miles.

The Daily News has decided to use 1,000 miles for both routes, which is a rough average.

But which is right -- or closest?

Iditarod officials begin reading mileage in Anchorage at the ceremonial start and continue through Eagle River, Knik, Wasilla and onto Willow -- even though the clock doesn't start ticking until mushers leave Willow.

Additional miles are added here and there -- Iditarod officials say it's 54 miles from Willow to Skwentna instead of the actual 40.

This tendency continues, with the most glaring discrepancy between Cripple and Ruby. The mileage claimed by Iditarod officials is well over 100, while the actual mileage is about 70.

GPS trackers are accurate to a fault. They measure straight-line distance very well, but they only read every 15 minutes.

Take a look at the interactive maps and you'll see this. GPS technology uses a string-line measurement technique -- that is, the shortest distance between readings. Dog trails are seldom straight, and there can be a number of zigzags in 15 minutes.

Accuracy is best obtained by a snowmachine odometer calibrated to the machine's track length. Iditarod trail workers avoid spinning their tracks -- and they usually travel in pairs, so mileage can be checked between machines.

I checked the run from the start at Willow Lake to Rainy Pass on a Ski-Doo Summit. Here's what I found:

Willow Lk to: Yentna Skwntna Fngr Lk. Rny Ps

Iditarod length 52 86 131 161

GPS length 39.8 67.5 106.1 133

Snowmachine 40 70.5 113 144

Both the Iditarod Trail Committee and the Michigan-based global-tracking company IonEarth, which provided each musher with GPS units, give team speeds on their Web sites.

Don't trust all of those -- you may suddenly see dogs seemingly flying out of Cripple on their way to Ruby. Speeds may get closer to reality between Nikolai to McGrath, where Iditarod mileage is relatively accurate.

On the other hand, the GPS tracker is exact at spot speeds. Unless a dog in the team is holding back to poop, you have the correct speed.

When figuring how fast a dog team is moving, remember that mushers stop to snack their dogs differently. Sebastian Schnuelle likes long, slower runs with fewer snacks, while Hans Gatt snacks his dogs on the trail every couple of hours.

No matter how you choose to figure speeds and mileage, there will always be some error. The best you can hope for is a good average.

While popular with many race fans, a few mushers, like Ed Iten of Kotzebue, chafe at being tracked.

"I didn't care for it at all," Iten said last year. "It's just a Big Brother thing."

Iten, a regular Top-10 finisher, is sitting out this year's Iditarod while his son Quinn, who at 18 is the youngest musher in this year's race, makes his bid for Nome.

And at least one musher has used the GPS as an opportunity for a practical joke.

Internet sled-dog junkies were stunned last year when GPS tracking showed four-time champion Martin Buser zooming off the trail at 130 mph. But the GPS wasn't in Buser's sled, it was in the air -- Buser had given it to an Iditarod Air Force pilot.

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John Schandelmeier of Paxson is a lifelong Alaskan and Bristol Bay commercial fisherman. A former champion of the Yukon Quest International Sled Dog Race, he was trail coordinator for this year's Quest and has written on the outdoors for several newspapers and magazines.