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Monday - June 11
Hugh and I had a very good meeting with the London Marathon Team- they have been contracted by the London Olympic Games Organizing Committee to provide the logistics for the marathon and race walks.
This included placement of crowd control fencing and the exact road usage for the runners.
Tuesday - June 12 (today)
It finally stopped raining around 10 am. I think here in London when they have a drought, they still report a 75% chance of rain! Smiler

Hugh and I biked the course to review the turns.
There is still some fencing and contruction materials around the monument in front of Buckinham Palace that might prevent us from measuring the race walk course. If that's the case, Hugh will do all the preliminary work and I will do a measurement that day.
We plan on layout and measuring a calibration course on the Mall (straight road way where the races start and finish). We are confident that this cal course will not have any obstructions during the Olympics. It should be ideal if we need to do any additional measurements.

One personal note:
You haven't lived until you have tried to follow Hugh on his bike throught the traffic of London. I have bike the path from his house to the Mall (start/finish) several times and will consider the Olympic measurement a success if I don't get killed before I have a chance to measure it!
David called me yesterday from London to tell me how the validation of the London Marathon course went.

It did check out to be accurate as to no ones surprise. David and Hugh had two exceptional rides. Less than 2 meters was the difference between each of their rides. David remarked that the London Police were many and helped with keeping the roads clear for both of them.

David had two unusual situation that day. First, before he got started his counter froze. Well, High came to the rescue with a spare counter. After completing the paperwork David had a spill on his bike. He went to the hospital to see if all was in order(his body not his mind). He states he is OK, but will do a further check when he returns home Friday.

Great job!
Gene
Thanks for posting.
I'm at Heathrow waiting for my flight back. I will know a little more about my injury Monday morning when I visit my orthopedic surgeon (I'm having an MRI today when I get home. There is some ligament/tendon damage to the knee but I have little trouble walking - infact, Hugh and I spent over 2 hours on Thursday making all of the adjustments for the splits.
Excluding my acrobatics on the bike, the trip was fantastic. I wish I could have spent more time with Mike Sandford. He is brillant and wealth of knowledge.

I keep looking at the numbers and trying to find that "red line" between practical application and silliness.

Hugh and I agreed within a few meters over the full 42195m - but a change in counts on the calibration by as little as one half count could swing the difference a few more meters.

It was a blast but I am relieved it's behind me. I think all of you would agree that the last thing you would want to do is screw up on the biggest measurement of your life!
It was a privilege to have the opportunity meet David at around 01.45 on Wednesday morning, and to be able to tag along in the measurement procession, which was in order: Hugh, David, Me. We also had a car with two event organisers from the London Marathon accompanied by a newspaper photographer, and of course the fleet of about 8 Metropolitan Police motorbikes with flashing blue lights to which Gene has referred above.

We set off round the course, the police riding ahead and behind, blocking side roads and closing down the lane ahead when the SPR took us onto the wrong side of the road. The process they use is one of repeated leap frogging. Once our procession of 3 bicycles had passed, the police motor bike guarding the side road weaved past us and took up position on the next unguarded side road ahead. I imagined that this must be what it is like to be in a Royal or VIP procession around Central London. Although as the police motorbikes expertly weaved past we cyclists it made me think also of the TV images of the Tour de France.

We had numerous brief stops to record intermediate distances, and for the police to clear traffic problems ahead. Central London is surprisingly busy between 2 and 4 am. On our second lap down the 4 lane Northumberland Avenue, we were on the right facing some huge lorries stopped ahead of us. The police expertly shuffled the traffic around so the lorries could cross to their right in order to leave the shortest line clear for us to ride.

Here is the group assembled on The Mall with Buckingham Palace lit by the rising sun very overexposed in the background.



Since I headed home to bed soon after the measurement, I did miss the opportunity for the traditional post measurement breakfast to work out results and to learn more about David's extraordinarily long measuring history. But we have agreed to make contact on Skype. I did however give David a short ride on my electrically assisted measuring bike and he seemed suitably impressed!
Foxy happenings on Westminster Bridge

I apologise in advance for this somewhat off topic post, but it amused me when my son Geoffrey who accompanied me to the Marathon measurement last Wednesday, showed me what he saw on Westminster Bridge.

While we were measuring the long lap, Geoffrey had walked to Westminster Bridge intending to capture us riders with Big Ben in the background. He stood on the bridge close to the second expansion joint, where I had told him we were turning. Unfortunately I had not explained that this turnround was only done on the first, short lap, so when our riding procession arrived with the flashing blue lights of the police escort, he was dismayed to see us turn right where the Embankment joins the bridge ramp and so not come towards him for the photograph.

However, while he waited he took a remarkable picture of a fox - right in the middle of the city - some distance from any park or other potential habitat. The picture has a lot of camera shake from a long exposure - but the evidence is clear of foxy activity.


We also had a professional photographer from the Wall Street Journal traveling with the measurement escort, and he took numerous pictures around the course. I understood that they were to be used for an article in the WSJ at the end of last week. I have searched the WSJ website but can't find any reference. Did any one see a picture in the WSJ? I would love to get a professional picture of the procession with the blue lights of the police motorbike escort.
David just sent me this link to the WSJ article published in today's paper.

A Marathon of Measurements

A smashing article - good PR for measuring. Well done David.

If you enlarge the picture of David with his tape you can see my son Geoffrey and myself in the background with my laser reflector box on the road: I tried to check the laser technique against the cal course length laid out by David's NIST calibrated tape. It convinced me that I need to improve my laser technique slightly.
Awesome article. Congratulations to both of you. David - 1.4 meters? Amazing.

Next , I want to see a YouTube video of you at the finish line of the marathon on race day. Surely at least one finisher will look at his/her GPS watch (sans calculator)and say "This course is long by 1/4 mile". I want to see your reaction upon hearing this (smile) ^^
A report appeared yesterday in NIST's Tech Beat blog concerning their calibration of David's tape.

I was interested to read that NIST does 40 tape calibrations per year, "mostly for the petroleum and measuring tape manufacturing industry." Does that mean if you are drilling an oil well you need to know how deep you are with a precision of better than 1 in 5000 which is what you would get from a class 2 tape?

The other interesting note was that NIST's temperature controlled tape tunnel can take tapes up to 60m. That must explain why the the tape report shows the tape elasticity was determined for the 40m to 100m interval. This measurement must have been made at the end of the work after the tape had been moved along for the 40m to 100m calibration readings.

The calibration report shows that NIST took readings with 10kg and 20 kg tension, which I did rather wonder about since class 2 tapes are always calibrated at 50N which is close to 5kg about 11 lbs. Perhaps class 1 (ie <0.01% error) tapes are pulled at a higher tension - I cant find the spec at the moment. However, looking at the calibration - this tape was not class 1 at 10kg, but would have been almost spot on at 50N.

Finally, I was interested to compare the picture of the precision laser interferometer which moves on wheels along a precision metal 60m runway, with the following picture of my laser on the back of my bike moving along the calibration course on The Mall: Same measuring principle; different accuracy.



Addition: I have now located the 1973 EU specification for tape measures COUNCIL DIRECTIVE of 19November 1973 on the approximation of the laws of the Member States relating to material measures of length. In the EU, 50N tractive force applies to both class 1 and class 2 tapes.
Last edited by mikesandford
Pete,
I supplied a set of PDFs to David with my analysis of the three riders' data we took back when we measured the course. I also included a copy of my analysis of the calibration course length.

My understanding at the time was that David wanted these documents to include in his overall report to the IAAF after the race. I have not heard anything from David during the actual games or more recently, so I hope everything went well.

Watching the races on TV, the line available to the runners looked pretty good. It was certainly not inside what we measured. There appeared to be a few places where the legs of the barriers intruded very slightly over the road kerbs and so would have increased the distance, but overall the amount was small enough that no question should be raised of the accuracy of the course as run.
I suspect that the blue line has been erased by now. They use one at the London Marathon too, and it's erased within a day of the race. City authorities don't want a permanent line.

The blue line is NOT the measured line. It's out there simply as a guide to let the runners get ready for upcoming turns. The measured line is tighter at the corners than the blue line, which is laid down with a special painting truck.

How would you get a copy of the report? Good question.
Wilhelm,
Pete is right. That blue line you could see in the TV pictures was a lot further out from the line me measured on the bends. The runners of course dont have to run exactly along the blue line - it just guides them in the general direction of the next corner. they need to run closer to the kerb to run the minimum distance.

Not sure what David itends to do about publishing his report after sending it to the IAAF. My own analysis of the 3 measurer's rides could be readily made available to interested measurers, but I think I should get David's OK first. He was the official measurer, I was just a hanger on.

Overall the whole measurment was excellently organised and we got excellent agreement between our rides. It was a great experience to be able to be part of it.

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