Saturday, November 27, 2010

I Love my GPS...kinda, sorta!

"Be careful if you don't know where you're going, because you might not get there" - Yogi Berra

As we steam through Thanksgiving, and prepare to slam head on into Christmas, I know many of you see me running with my Garmin watch and sigh and say "I want to be like Coach AL and know to the hundreths of a mile how far I've run every step". Well, first of all, if you're a regular reader of this blog, you know I wrote a piece a while ago about "Don't be like Mike" or anybody else, especially me! Second of all, although I am in love with my watch (my therapist says I'm showing some slow progress but would show more if I tried), it distressingly will show SLIGHTLY different distances over the same courses, so why the heck does this happen?

We've all seen it. You're at the finish of a long training run waiting for the rest of your group to come in. Here comes one of your buddies, flying into the parking lot, staring at his watch. Out of his mouth comes "Damn Garmin", and around the parking lot he goes for 0.17 more miles to get that FULL mileage in. The fact that we've run this same course a thousand times and call it XX miles does not phase our anal runner. OK, that anal runner is me, but that's beside the point. What has GPS technology done to us? Well, for one, it has us questioning every race director that his course is a smidge short or WAY long. Afterall, we've measured this course in our car and now have this fancy $300 watch to tell us EXACTLY how long the course is, and the RD is telling us something different?

Like every owner of a GPS watch, I have this picture of locking into a satellite (actually several) and that satellite has a laser locked on just my head and doesn't waver one iota to let me know to the inch how far I've traveled. So, how come when I run my same course on my morning runs, it might be a couple of hundreths of a mile different (I told you I was anal) with each run. I decided I was going to research this and here's what I found.

Surprising to me, there is no direct line laser beam shot from the satellite to the top of my head that will stick to me no matter where I go. Instead, the GPS on my wrist must recieve a radio signal from at least 3 satellites - the more the better. Now, this is cool - the satellites then "triangulate" me and the distance from my fancy watch is then calculated to EACH satellite. From here, my watch says "here you are". Then, a little time later (usually 1-5 seconds), a virtual Captain Midnight raygun shoots at me and lays a dot in the land. Now, me, being the principle component of this whole deal, literally keeps moving, dots are laid, and my Garmin, like a faithful puppy dog follows me along. and when the dots are connected, the distance is proudly displayed. Man, that is cool, BUT there are a few flies in the soup.

We all know about these Garmin rayguns not being strong enough to penetrate buildings, tunnels, or even a thick canopy of trees. If you plot out your course on the computer after running a downtown route, it might look like you've taken a jolly jog through the buildings instead of along the sidewalks. Like to run the trails? Well, Mister Garmin doesn't like that because he loses you once in a while. Now, when he does spot you down the trail here and there, he will fire another shot at you and connect that dot to the last dot he fired. The fact that you've run 1.2 miles zig-zagging along a single track means nothing to technology that sees the last two dots only 0.3 miles apart. It has done it's job finding you and laying those dots. Technology has improved significantly from those very first Garmin 101's that would lose the signal if the bill of your cap got inbetween the satellites and your brick-size watch, but it still can be frustrating for the aforementioned, trail-running Coach Anal.

Finally, when Garmin's satellite shoots it's raygun at you, it is only guaranteed to land within 3-10 (about 10-30 feet) meters from me, and that's if I'm running with no "blockages". Remember that faithful puppy dog analogy above? Well, sometimes Fido sees a squirell and takes off after it. Fido will return, but he's putting in a little different mileage that his master (you or me). A good test is to go to a 400 meter High School track, run on the inside white line for a mile, go home and plot the run on your computer. You'll see that tracing of your run weaving like a drunk sailor from the infield to the second lane.

One other problem I hear often is with running hills and "how can the mileage be accurate if I go up and down?". Well, even though Coach Anal doesn't like it, the fact is if you run up an 11% grade for a mile (roughly the grade of Pikes Peak), you will run only about 30 FEET longer than you would if you ran that mile on a completely level mile. Ah, the good ol' High School Pathagorean Theorem.

So, on a long run, add up all those extra dots, missed dots, and general "chasing squirrels", you can see that your incredibly accurate GPS has it's limits. BUT, and it is a big BUT, remember, this is a running watch... on your wrist...while you are running! It is not some part of the NATO Strategic Air Command. I still think it's pretty incredible and a very welcome training device compared to the old days when I would finish my run, jump in my car, and clock the distance with my always incredible car odometer.

Ok guys, that's about it from RWA Central this week. I hope you all had a good Thanksgiving. I got through the whole post and didn't even mention the Alabama/Auburn game. All I can say is WOW! It's going to be hard for UAB/Rice to top that. For any of my out-of-Alabama readers, just ignore the last sentence...this state is sort of manical about it's college football. Meanwhile, my son, daughter-in-law, and granson, Adam, are spending Thanksgiving with us, so I will be absent from our training run tomorrow. Had to choose between running 17 miles or making pumpkin pancakes. Decided to practice the carbo-loading! Surprise!! I will see you all on the acurately measured roads (by my GPS) next week - AL

"One child lost is too child saved can change the world"


chunky girl said...

LOL - I don't mind so much on training runs but it drives me nuts when I'm in a race and think I'm holding my pace only to find out afterwards that I ran .3 of a mile longer on a Half (and my pace was commensurately slower!)

AL said...

So, you can always say you ran an Ultra Half Marathon!!! Also, it was your 13.4 mile PR!! See how easy it is to turn things in your favor?