Here are the usual suspects after completing the verification measurement of the 2009 Flora London Marathon. L to R: Pete Riegel, Tom Riegel, Hugh Jones, Mike Sandford.

Can I assume you all used the new JR model of the Jones Counter?

Come on Pete. Who had the best ride? I know the numbers have been crunched.

All the bikes used the Jones Counter, Model JR.

Late in the week we were informed that Tamil demonstrators in Parliament Square might interfere with the race as it passed by, so a different final mile was conceived and measured Friday by Hugh Jones. He gave me and Tom a sketch of the route and we went out on Saturday, the day before the race, to check it. We used a “Nicoll Wheel,” a measuring wheel made of a bike front wheel with a Jones Counter (NYRRC version, circa 1980’s) attached. This wheel was invented by Wayne Nicoll. I made one (with a solid tire) and gave it to John Disley many years ago and never used it until this year. It's far better than standard surveyor's wheels for our use.

We measured between two reference points which spanned the two routes. Distance between the points measured 8025 counts by the standard route and 8007 counts by the diverted route. The wheel was calibrated by rolling it along a 10 meter stretch of tape, getting 95 counts, twice, for a rolling constant of 9.5 counts per meter. By this we figured that the diverted route was 1.9 meters shorter than the original route.

This was a fun morning, as we had to go through Horse Guards while Trooping the Colors was in progress, and mounted troopers occupied the SPR. We thought of shouting at them to move for us, but decided to wait instead.

It was a fine morning out, but wasted, as the original route was used.


Here’s Tom holding the wheel, above


Above: Here we are at Horse guards. We are waiting for the path through the gate to open up.


As for comparative numbers, we had only one reference span that had been adjusted since last year. It went between a lightpole on North Colonnade of Canary Wharf to lightpole 53/22 on Poplar High Street. This distance was measured as follows:

1352.16 m - Hugh Jones
1356.22 m - Mike Sandford
1353.83 m - Tom Riegel
1353.63 m - Pete Riegel

We also measured an arc of cones along the finísh route. The arc divided two finish flows of runners. We all got an answer that said the cones added between 6.2 and 7.4 meters to the course. This, as well as the measurements in Canary Wharf, confirmed earlier measurements by Hugh, and no adjustments to the course were seen as necessary.

Note From Mike Sandford

From my GPS:

Canada Sq SE lampost is Waypoint 8
Grove on Bridge Trafalgar is Way Waypoint 9
Lamp Post LP P5322 in Poplar High St is Waypoint 10

8 to 9 GPS 183 raw data points at 1/ second give 571 m and when when smoothed give 529 m The Jones counter dist was 474.0 m
9 to 10 GPS 212 raw data points at 1/second give 898 m and when smoothed give 882 m . The jones counter distance was 882.1 m

I have attached the unsmoothed tracks superimposed on a street map. You can follow my approach to way point 8. There were big fluctuations in position up to 50 m as we got reflections and screening from the tall buildings.



The normal smoothing which I applied did not remove these fluctuations. This is because the smoothing method I used is to replace the scattered, once per second, points with a straight line. and when a point veiates by more than two metres from the line I start a new straight line. (This is done automatically by a programme on my computer). The result is that the smoothed distance measured by GPS from waypoint 8 to waypoint 9 is much larger than the Jones Count distance.

From Waypoint 9 to waypoint 10 the GPS gives a distance less than 1 m diffent from the Jones. This is becasue there are no tall buildings giving reflections for that section.

You will observe that the trakcs from 9 to 10 at some points don not follow the road exactly. This may be due to imperfections in the map. I suspect it may be a rather schematic representation of the roads. I will try and get an aerial view and see if the tracks fit better.

My GPS is much better on the open roads around Abingdon than between the tall buildings at Canada Square.

Addition by Pete: The map shows why the four measurements were not more closely grouped. Three roundabouts, several corners, and a long bend, all in a stretch of about a mile. Our measured route went from waypoint 8 to waypoint 10 only.