Duane: The working party is a committee of measurers in the UK that prides itself doing work. It would be approximately an equivalent of your RRTC committee. Like you we have one meeting per year - all the rest is done by email.
There is a long term trend of increasing pressure in many areas of the UK to get races moved off the road. This often applies to the smaller races who cannot afford road closures, that the very large events can afford to put in place.
We are faced with the problem that many runners want their race performances on these non-road surfaces, recognised for ranking lists which have been getting increasingly popular even among the non-elite runners. Our National Body has asked at what we can do about providing a standard of measurement for them which will be better than relying on the claims of the race director working from GPS or from maps/google. At the moment we are feeling that we could measure them but we don't know what to say about accuracy. What we are fairly clear about is that they don't meet the surface standards for an IAAF road race, and according to the UK rules of competition for road races, these must be measured to IAAF standards. Hence the demand for a new measurement class in the UK.
quote:Originally posted by Bob Thurston:
Technical question, can someone tell how to include a table for a submission? I made a little table, tried to copy it but then found it was kind of screwy. So I made it look "right" in the little message box-- but now it is kind of run together.
Bob, following up on Mark's reply: in Windows 7, find the "Snipping Tool". Drag the icon to your Windows task bar. Open up the table you wrote. Use the Snipping Tool to cut out the table and save it, as Mark said, as an image: .jpg will work best. Then, upload the image to Picasa or Dropbox or the free photo site of your choice. In that program, select the image and use the program's options to define a URL for that image alone. Copy that URL to your clipboard. Next, open up the message screen in this forum. Click on the little green square (3rd from the right)at the top of the message screen and type or paste in the URL: [IMG]Image URL Here[/IMG] Instead of this text, your table will appear.
Circuitous, and maybe not worth the effort? I understand. However, this forum does not support direct pasting of image files (other than its smileys
), so this is what we are left with.
"... He suggested that we might institute 3 levels of certification:
1 Road courses.
• Sealed road or pavement - less than 5-10% other surfaces.
• Issued with a Certificate of Course Accuracy showing compliance with IAAF
requirements for road races.
• Logo wording is CERTIFIED ACCURATE.
2 Gravel courses.
• Sealed road and/or good compacted gravel - less than 5-10% other surfaces.
• Issued with a Certificate of Distance confirming a full-length course, but not
claiming to be comply with IAAF limits of accuracy for road races.
• Logo wording suggested – DISTANCE CONFIRMED
3 Off-road courses.
• Over 5-10% on surfaces other than sealed road or good compacted gravel.
• Issued with a Statement of Course Measurement confirming the measurement
method used but stating that 'the distance recorded is measured only as accurately
as the definition of the course and the course surface permits'.
• Logo wording is MULTI TERRAIN.
Mike, this 3-level approach strikes me as a sensible way to deal with the problem of "non-sealed" surface course measurements. This question has come up recently in my local running club due to the wide variations between some off-road advertised course distances and the sense many runners have of a particular course's distance.
For example, the "Stone Mill" trail race is advertised as a 50-miler. This advertised distance is based on patching together many pieces of wheel-measured sections with Google Earth estimates. Experienced trail runners and GPS-wearers in this race have consistently maintained that the actual distance is something like 54.2 miles. In the case of a single-track trail race like this one, I propose we consider a fourth category: "SINGLE-TRACK BEST ESTIMATE".
I assume for this definition that it is normally preferable to rely on two or more runner or biker GPS readings of the course taken during times of no canopy cover than to trek 50 miles with a wheel. I propose that, if the GPS readings so obtained fall within some threshold of agreement, say .03%, then the average of these readings be accepted for this "Best Estimate".
Supporting observation: it seems to me that comparisons of wheel measurements of single-track trails to GPS measurements tend to demonstrate lower mileage numbers for GPS devices. This is assumed to be related to the fact that consumer-quality GPS devices tend to "under-capture" the many sharp turns and small, rapid elevation changes in single-track trails. Therefore, it seems likely that GPS estimates of single-track trail distances will slightly understate rather than overstate the "actual" (e.g. theoretical steel-taped) distance.
I am curious to hear what the technical folk here think of all this.
1 Road courses.
• Sealed road or pavement - less than 5-10% other surfaces.
• Issued with a Certificate of Course Accuracy showing compliance with IAAF
requirements for road races.
• Logo wording is CERTIFIED ACCURATE.
2 Gravel courses.
• Sealed road and/or good compacted gravel - less than 5-10% other surfaces.
• Issued with a Certificate of Distance confirming a full-length course, but not
claiming to be comply with IAAF limits of accuracy for road races.
• Logo wording suggested – DISTANCE CONFIRMED
3 Off-road courses.
• Over 5-10% on surfaces other than sealed road or good compacted gravel.
• Issued with a Statement of Course Measurement confirming the measurement
method used but stating that 'the distance recorded is measured only as accurately
as the definition of the course and the course surface permits'.
• Logo wording is MULTI TERRAIN.
Mike, this 3-level approach strikes me as a sensible way to deal with the problem of "non-sealed" surface course measurements. This question has come up recently in my local running club due to the wide variations between some off-road advertised course distances and the sense many runners have of a particular course's distance.
For example, the "Stone Mill" trail race is advertised as a 50-miler. This advertised distance is based on patching together many pieces of wheel-measured sections with Google Earth estimates. Experienced trail runners and GPS-wearers in this race have consistently maintained that the actual distance is something like 54.2 miles. In the case of a single-track trail race like this one, I propose we consider a fourth category: "SINGLE-TRACK BEST ESTIMATE".
I assume for this definition that it is normally preferable to rely on two or more runner or biker GPS readings of the course taken during times of no canopy cover than to trek 50 miles with a wheel. I propose that, if the GPS readings so obtained fall within some threshold of agreement, say .03%, then the average of these readings be accepted for this "Best Estimate".
Supporting observation: it seems to me that comparisons of wheel measurements of single-track trails to GPS measurements tend to demonstrate lower mileage numbers for GPS devices. This is assumed to be related to the fact that consumer-quality GPS devices tend to "under-capture" the many sharp turns and small, rapid elevation changes in single-track trails. Therefore, it seems likely that GPS estimates of single-track trail distances will slightly understate rather than overstate the "actual" (e.g. theoretical steel-taped) distance.
I am curious to hear what the technical folk here think of all this.
I think it's just as likely, or more likely, that a wheel measurement of a trail with many turns and uneven and loose footing would be inaccurate. For such a course I would trust a carefully done GPS measurement over just about anything else. But there's a big difference between a carefully done GPS measurement and what a random Joe will tell you his Forerunner said.
I think this a can of worms that we don't need to open
Dave, I understand you. This may seem like a solution in search of a problem. The reason I see it differently is because of the recent increase in the number of and participation in trail running events in my region and in the U.S. I will poke around in some trail running venues and ask some trail ultra runner friends what they think about some kind of measuring standard for single-track races. In the Mid-Atlantic area, this kind of event is flourishing. There is constant discussion among participants and organizers of these events about how long/short a particular course may be compared to its advertised distance. These differences are usually non-trivial. An 8+% underestimate in a 50-miler means participants run at least 4 miles more than they expect to. I ran a trail "marathon" once that GPS-wearing runners claimed was more like 29 miles. I believed them, based on my intuition.
Since participation in trail races is large and growing, why not establish some kind of criteria for distance estimates so that trail race runners enjoy benefits that are at least "somewhat comparable" to those that runners of certified road courses, or at least as reliable as Mike Sanford's "Gravel" or "Off Road" criteria? These GPS measurements would adhere to procedures and quality checks that we devise and test. For instance, establishing minimum GPS device track log "time slice" and memory requirements. Requiring measurements be taken only when there is no overhead canopy would be another standard.
I agree with Mark that "a carefully done GPS measurement" would be more worthy of our trust than any other currently available method for single-track events. Hence, an opportunity to establish sensible guidelines or measuring requirements for some kind of USATF imprimatur. Something better than "Random Joe with his Forerunner", which is all these athletes have available to them today.
Establishing a single-track measuring system can provide distance and performance comparability between trail events. It will allow for "truth in advertising" for trail race distances. It will help line up trail runner expectations more closely with whatever the actual distance run might be. I believe it is a service to the running community that we can and should look into.
Since participation in trail races is large and growing, why not establish some kind of criteria for distance estimates so that trail race runners enjoy benefits that are at least "somewhat comparable" to those that runners of certified road courses, or at least as reliable as Mike Sanford's "Gravel" or "Off Road" criteria? These GPS measurements would adhere to procedures and quality checks that we devise and test. For instance, establishing minimum GPS device track log "time slice" and memory requirements. Requiring measurements be taken only when there is no overhead canopy would be another standard.
I agree with Mark that "a carefully done GPS measurement" would be more worthy of our trust than any other currently available method for single-track events. Hence, an opportunity to establish sensible guidelines or measuring requirements for some kind of USATF imprimatur. Something better than "Random Joe with his Forerunner", which is all these athletes have available to them today.
Establishing a single-track measuring system can provide distance and performance comparability between trail events. It will allow for "truth in advertising" for trail race distances. It will help line up trail runner expectations more closely with whatever the actual distance run might be. I believe it is a service to the running community that we can and should look into.
If you did accept GPS data for an "off-road" certification, additional requirements should include the GPS device being mounted to the bike (not the person), two measurements of the course (but I would probably relax the 0.08% requirement a good bit), and submission of raw track data from the device for both rides.
As Lyman says, you would just be trying to ensure that a 10k trail run was within a 100 meters or so of the correct distance. GPS is certainly capable of that if used properly.
As Lyman says, you would just be trying to ensure that a 10k trail run was within a 100 meters or so of the correct distance. GPS is certainly capable of that if used properly.
GPS is capable of that if used properly and there is no interference from trees or buildings.
I measured a cinder trail that is primarily under trees. When I put the track into GoogleEarth, the track varied left-to-right by over 50 feet. When I measure a 1-mile downtown street, the track shows me going into buildings on either side of the street. This is also not accurate.
Just want to reiterate that GPS devices must have a clear view of the sky, and free of signal-diverting obstructions to the side of the route.
I measured a cinder trail that is primarily under trees. When I put the track into GoogleEarth, the track varied left-to-right by over 50 feet. When I measure a 1-mile downtown street, the track shows me going into buildings on either side of the street. This is also not accurate.
Just want to reiterate that GPS devices must have a clear view of the sky, and free of signal-diverting obstructions to the side of the route.
I agree with David. I feel that Cross Country/Trail Running has too many variables to accurately measure their courses. if this group would like some sort of standard, then it should done under their LDR divisions group(not the RRTC).
With my GPS device, 60csx, I have seen the obstruction issue only with tall buildings, never with tree cover.
But anyway, that's why submission of raw track data would be part of the requirements, to make sure obstruction wasn't happening.
But anyway, that's why submission of raw track data would be part of the requirements, to make sure obstruction wasn't happening.
I still say that there are unpaved courses that can be measured quite well using our bike counters. This works best when using a cal course with similar surface qualities but can also be ok when calibrating on smooth pavement. I think the major drawbacks to measurements have to do with whether or not the course is "definable", not so much what kind of surface is underfoot.