Course Revisions-is Re measurement Necessary

What you propose is acceptable- but given that the course is only a 5K and you don't sound like you have a lot of experience at this, I'd advise that you start from scratch.

These things can get confusing even for some of us who have measured hundreds of courses. I counsel anyone who asks to start from scratch rather than try to do something like this to a 5K course.

If you have already laid out an adequate single-point TA, you need not measure the course again.

You can establish a new TA having a radius of, say, 4 meters simply by figuring out how much is added and subtracted.

A single-point TA has the runners using a radius of 10 cm.

Your new TA of four meters radius will have the same 10 cm offset, but the runners' path is longer.

Simply figure the difference between the two paths and move the TA radius center toward the start so that the distance lost is equal to the distance gained. The only measurmeent needed is the short taping that records the shift of the TA center point.

No need to bike the whole course again. That is absolutely unnecessary and a waste of valuable time.

Gentlemen thank you for your responses. They are greatly appreciated. For the record I don't have a problem with remeasuring the entire course other than the frustration of having thought I achieved my goal of measuring a very accurate course only for it to be flushed in an instant. I could go with the original TA but that's not me because I want the course to be the best I can put forward for the runners. Happy runners come back year after year. Unhappy runners don't come back.

Let me explain further. The TA is on a paved pedestrian path about 12' wide. Completely adequate for one way traffic but not so sure about two way (anticipated 150-200 runners). The path is bordered on both sides by obstacles (trees on one side, building on another) so I can't go off the pavement. I can't move the start or the finish lines enough to get the TA into a larger space. So the relocation of the TA means going back out to the main campus road to mark an artifical starting point. From there I go onto a stretch of sidewalk and instead of turning left to the path (current TA) I make a right turn to a stretch of path/road which is much more wide open and can easily accomidate a comfortable TA. The out and back from the common artificial starting point to the TA is roughly .25 miles. Once again, I am completely confident that I can revise the TA and achieve the exact number of counts while maintaining the shortest possible route. It just will not be part of one original measurement sequence.

Dear Jack,

Thanks for the clarification.

Measure back from the original TA to a point on the main campus road. Establish a reference point and calculate how many counts (say “x” counts) you collected from the original TA.

Begin again at the reference point and ride x counts to your new TA. Ride back to the reference point, take a count, then ride to the original TA and take a count.

You will have measured everything twice.

You need not even calibrate the bike.

Thanks Pete. That's what I'll do. In addition, I will document everything thoroughly with the state certifer for New Jersey. If he has a problem, which I doubt he will, I'll do a complete remeasurement in the spring. Getting a little nippy out there this time of year. Thanks again!!

Jack,

Pete and Jay are two of our most experienced Certifiers and have answered your situation as I would have done.

It's great to see we have a new measurer like you with your enthusiasm.

Keep measuring and best of luck with your race.

I have another thought on this. I suggest you check with the NJ Certifier and submit the numbers you have. Next, explain what adjustment you are doing. If the initial work is approved, then the NJ Certifier should give you the go ahead to do the adjustment.

Jack, a thought for future measurements: Bob Thurston, also one of the most experienced certifiers, taught me to record interim points during each measurement. These points could be the preliminary mile or kilometer marks, or just random spots that are easy to mark with chalk or tape, or which can be identified exactly with respect to fixed objects. For the typical 5K, 2 to 4 of these interim points should be sufficient. Record your Counter reading for each spot on both rides.

Retain this data for later use when something like your course change comes up. Using the recorded interim point from the shortest (fewest # of counts) of the 2 measurements in the section that is closest to your area of revision, i.e. a new turn around, you can re-measure just this section with the revised route. When you measure it twice, you again take the shorter of the two, note the # of counts you have added or subtracted (added, in your case), and adjust the start, the finish, or the start/finish accordingly. Of course, if the start and finish are contiguous, you divide the adjustment counts by 2 to lengthen or, as in your case, shorten the S/F line.

Doing it this way prevents you from needing to re-ride the entire course. If the redesign is for longer distances than 5K, you will appreciate having these interim points to go back to. Of course, if the course change is more than a couple of feet or so, you may want to adjust the mile marks. Again, if you have recorded the mile marks on each and every ride, this task becomes relatively simple.

Measuring this way essentially does what Pete's method does. The difference is that you may save some time and effort in future measurements with changes when you already have interim points recorded. Bob Thurston takes this to another step: after the initial two rides, he compares each interim section measurement and then he selects the shortest of the two and enters them in a new column. He then adds all of these shortest sections. Since it happens sometimes that you get a better (shorter) measurement on the first ride than on the second in any given section, you now essentially reduce the course measurement to the combination of the best section measurements.

I am not quite as new at measuring as you, but this "interim" technique is somewhat new to me. I imagine this has been discussed in the past here, before my time on this Bulletin Board. I am curious how many experienced measurers and certifiers regularly employ this technique.

Lyman, the technique you describe is the "Sum of Shortest Splits (SOSS)" which is in the Manual (or at least it was in earlier additions). Bob Baumel's old Measurement Program, which was written in Basic and no longer runs on newer operating systems, provides that figure as the final course length figure. Using it will mean your course is almost always longer than the SCPF requires; it is a very rigorous method, but worth using in some situations.

I'd amend SOSS to be "Sum Of Shortest Segments".

If I perform two measurements of the entire course, from one end to the other, I naturally use the shorter one as your course length.

When I measure the course in a number of segments, I match up all of the long measurements of each segment and add them, and all of the short measurements of the same segments, and add them. The sum of the shortest segments is the course length.

I wouldn't do this with every intermediate split; you could drive yourself crazy over a long course. But when measuring in distinct segments, it's one more level of insurance against compensating errors generating a short course.

Thanks, Jim. Thanks, Jay.

With some course I have measured, One, two or more "reconnaissance rides" or "course design" rides have been necessary before even beginning measurement rides. I find this happens most often in rapidly-developing areas like nearby Loudoun County, VA where the available aerial imagery is insufficient for on-line estimates. By the time I get all that riding done, I am usually not in a mood to use a Sum of Shortest Segments technique. And, after all that much work, I usually have sufficient confidence in the route to ride all the tangents as tight as possible.

Apparently my mentor, Bob Thurston, uses SOSS as a matter of "course" (haha). He also routinely travels back to the course being measured after performing post-cal to make the final adjustments. I had been in the habit, if the temperature had increased consistently over the course of the measurement, and when the post-cal seemed right in line with expectations, to simply adjust the final few feet on the timing points description on the map. Of course, the problem with this is that timing points paint marks might then be inaccurate.

How do you experts handle this?

Lyman; I've not met Bob Thurston, but I use the method you attribute to him. For courses measured in segments, I use the sum of the shortest segments. In all cases, after the 2nd cal ride, I return to the course for final adjustments and marking, even if this happens on another day. The sum of the shortest segment method usually requires a separate ride of the entire course for establishing the intermediate (mile) splits. I send a measurement data form for each segment, plus a measurement data form with a summary of the segments totaling to the distance of the course. It may seem like extra work, but I've used those measurement data sheets several times when courses had to be recertified because of changes.

Thanks, Guido.

You say "For courses measured in segments..." Are you referring to courses that require more than a single day of measuring? It sounds as though you do not measure all your courses as SOSSes.

This does seem like a whole lot more work. My initial take is that, maybe all races are not equal. For a hilly Mom & Pop 5K, it does not seem justifiable to employ this method.

I see the benefit when the race is longer and/or higher profile.

Any guidance, recommendations, suggestions and/or comments from anyone out here is appreciated.

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Road Course Measurement Bulletin Board Forums Newer Measurer Questions and Information Measuring the Course Course Revisions-is Re measurement Necessary

Whoa! I thought this thread was over and I looked and it wasn't by a long shot. I can't thank you guys enough. I have been reading page after page of bulletin messages trying to pick up anything I can. Anyone who thinks that there isn't a science to this should not be measuring courses. I learn something new every time I read a thread.

As a follow up to my original post, I am waiting for the state certifier to either certify the course or tell me to start over. He had a question for me the other day but it had nothing to do with my measurement so I think it will be fine. I was very clear about what I did and even provided a map of it.

I have one certification under my belt as of now (this would be number 2)and while it may sound juvenile, I am proud of it. Seeing that certification is a thrill and makes you want to do more.

Thanks again to all.

Jack, none of these discussions are ever "over". We can look at any situation from 312 ( I think that is the number of registered users ) different angles. Each of us have encountered different challenges, so we all learn from each other, even if we have measured over 100 courses (many have measured many more than 100 courses).

Your observation is correct, in that this BB is a great source of new information. However, it can also be habit-forming, and can become a diversion from household chores.

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Your observation is correct, in that this BB is a great source of new information. However, it can also be habit-forming, and can become a diversion from household chores.

...yes I'm finding that out. Haven't hit the archives yet, oh boy!

Lyman: We use segments mostly for marathons and half marathons, whether measured on one day or several days. Deciding when to use a segment is guess work at best. Usually the guess is based on what the race director may want, or what I think of the chance that the course will be changed to accommodate traffic or less police or runners' complaints. 5Ks and 10Ks don't usually warrant segments since they are easy to remeasure.

Guido, this is what I expected you might advise. Thank you.