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Saved by Google Earth: A Last-Minute Check Barely Averts Disaster
Or, Why We Measure Twice
Bob Thurston

It had been a long day, starting when I was awakened by a call from Jim Gerweck, who had heard that the Cherry Blossom 10 Mile had been diverted due to a police emergency. At Jim’s suggestion I called race director Phil Stewart, who confirmed the story and then described exactly how and at what point the runners were diverted from the course. Since course measurer John Sissala was out of town, the next question was, when could I measure to find the actual distance run? I told Phil I would do it that day.

With beautiful weather and cherry blossoms at their peak, this was not really the greatest day to measure downtown. At least I knew there would be no place to park, so I made the trip (~15 miles there and back) by bike. The bad news is some of the streets were chock full of cars; the good news is, they weren’t moving, so you could squeeze alongside as long as you kept a sharp lookout for doors popping open (folks jumping out to get to a bathroom, to take a picture, or to actually get somewhere other than the traffic jam).

After a couple of slow-moving hours, I had my results: the course was short by 0.46357 miles, or about 816 yards. I reported all this to Phil Stewart, and I worked out 10-mile equivalent times for winners and other key finishers. Phil told me they were going to wait a day or so before announcing this result. It turned out that one of those converted times would have “broken” an American record (the event offers a bonus up to $10,000 for breaking Greg Meyer’s 46:13 set in 1983, and/or Janet Bawcom’s single-sex American record of 52:12 set in 2014). The race committee needed to decide how they were going to handle that before word got out. The delay would turn out to be very lucky for me.

Fairly late on Sunday evening, I decided to write up the measurement results while everything was still fresh. To further illustrate what had happened I thought I would create a Google Earth measuring path for both versions of the course: the correct course, and the path the runners were forced to take that morning. I remember thinking, “These paths are really good—this result is going to be within a few meters of what I found out there on the course.” Then I clicked on the two distances, subtracted, and found to my horror that the difference was something like 1078 yards, nowhere near the 816 yards I thought I had measured!

I look again at my notes. Here’s the point where the emergency course and the real course come together. I write “CP (for common point) 1st pole on Ohio after curve”. Oops. There is no number written there. The line below has a number, but beside it, the note “S (south) edge, 14th St Bridge”. Well that point is beyond the common point. Right away I get it: looking at these notes earlier, I was thinking “I had to have written a number down at the common point—it must be this one on the line below.” Wrong—the truth is I just didn’t write down a number at the common point. I just wasn’t willing to face the truth at the moment (and I sure didn’t want to go back through the traffic jam and measure again!).

I write a quick note to Phil (“Hold everything . . . I messed up bigtime . . . will remeasure . . .”). It was after midnight but I knew I wouldn’t sleep well if I left this for the next day. I went down, calibrated, rode both ways, recalibrated, and basically confirmed the GE measurement. The course was 0.61347 miles short, about 1080 yards—the actual distance run was 9.38653. The conversion factor is (time run, in seconds) x 1.06536 = (projected 10 mile time in seconds). Significantly, this means that the best American male time of 43:38 converts to 46:29 (>46:13).

I texted all this to Phil Stewart, and then drove home. I slept well, knowing I had narrowly escaped extreme embarrassment—thanks to the Google Earth check and to the race committee’s delay in making an announcement. And I had relearned some lessons I had allowed to rust a bit:

• Always write down a number and what the number means! (A good habit is read the counter number, write it down, read the counter again, look again at what you wrote. If only I’d done half of that!)

• Measure twice. It helps avoid getting seriously embarrassed!

• Check your work.

• Measuring at night can work really well. My midnight measurement took 30 minutes, including both pre- and post-calibration—compared to about 2 hours during the daytime (not counting commuting time). Of course you need lots of lights, flashing and other, when you are doing this. I use a bright helmet-mounted light that works better than constantly fishing out a flashlight.

• Sometimes a little delay can be a good thing. It was this time.
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It's not too hard to measure when there is so much traffic that it is barely moving. I did learn that with so many lanes of cars in the road, I would not be able to "sight" across to my favorite landmarks for switching from one side to the other-- I like to pick a nice perpendicular line near the edge of the street, like a storm drain edge or something-- but on this day I had to use the light poles, the only thing you could see above the traffic.

If anything you may tend to measure distances as being slightly shorter than the SPR when you measure by only using road edges (always on the shorter side when road is curving). For instance there was a place where cars were right next to the curb, and I had to measure on top of the curb. If you are laying out a course this is not so much of a problem but if you are measuring a distance being subtracted due to a course adjustment or emergency, this can be a problem-- if you understate the distance being subtracted you might end up overstating the final course length.

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