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Great North West Half-Marathon
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An interesting point about Garmins. I use one (mainly on my bike) and they are brilliant for both navigation and distance measuring.The latest generation are very accurate indeed-you can buy something for £100ish that will tell you where you are anywhere on the earths surface within a few feet. But hold on! I dont think I dreamed it but didnt someone claim on this forum that the Blackpol Mararthon wasnt short and that there was a GPS 'blind spot' at the end of the course -ie everyone wearing a GPS got a wrong measurement?Wasnt this where the ship ran aground? This must explain it-the ship must have lost its navigation system. I'll get on to the Marine Accident Investigation Board imediately!
As a general point I wouldbe inerested to know (maybe from course measurer Brian) how far a course would be out by just walking/cycling round it with a good GPS rather than the calibrated wheel system.Will this technology put Brian out of a job?
PF-I just wanted to establish some gravitas before I got going with the jokey stuff!!!
Happy to answer that one, OldPoster.
Garmins are generally between 99 and 99.5% accurate compared with the calibrated bike system.
The main differences being that GPS systems use triangulation whereas the calibrated bike is the actual route taken.
Also, GPS devices don't include the 0.1% short course prevention factor.
But GPS devices are a useful aid to course measurement and I usually have mine with me as a guide.
Brian-Is the .1% somethong that you deliberately add on to each course in spite of measuring via the optimum line of running? So a marathon,if measured perfectly accurately would be about 50m over length? if so I am knocking 5secs off my PB as I am sure I ran the last 50m like an olympic sprinter.
Do you get the 99-99.5% figure based on a direct comparison between what your wheel measures and what the Garnin measures following exactly the same line? I would have thought that the latest generation of hand held GPSs, when used at their most sensitive, would be very much more accurate than within 400m (ie1%) over 26miles. As a test I will strap my GPS to you when you next run on the track and see the error between the official 3000m and what the GPS says. Of course the GPS will also take into account the rise and fall over the barriers.
Old Poster - welcome to our crazy world
But this thread is positively staid compared to Freckleton. Int that right Brian?
you are right there PF
running is getting faster now got my number for the stoke-on trent half mararthon
MT - where have you been? You've been quiet the last few days - not even popped into the Frecky thread.
I don't like the sound of this faster lark - how will I ever beat you if you don't let me race you while you're still injured?
went running and swimming on tuesday my bothers last night only come on late tonight
I been reading the frecky thread getting better
Yes, OP, the 0.1% is added on to all measurements, so a marathon is 46 yards "long". It's the same method used interntionally and has been agreed by the IAAF.
The accuracy figures I posted are based on research by a number of measurers. The new generation of GPS devices are certainly more accurate and would possibly take into account the rise and (in my case considerable fall) over steeplechase barriers, but there do not appear to be any plans to adopt gps devices for course measurement.
As you have such detailed knowledge of my steeplechasing prowess, you will see the irony of my ability to measure courses to IAAF standards, but not to run to those standards................
(But I still have a Lancashire County bronze medal for it
)
You may find this interesting too:
GPS versus garmin
The full IAAF measurement document: (all 88 pages) IAAF course measurement
And the UK course measurement web site: course measurement
But don't blame me if you fall asleep reading it...........................
[1] Hi Brian Porter. I met you at the Course Measurement Upgrade Seminar in Blackpool last year, good to see you on here spreading the gospel.
Re-the accuracy of garmins, it is worth adding that much depends on the prevailing conditions. In optimum conditions garmins are very good. I have measured a 7 mile circuit by calibrated bike on the flat expanse between Southport and Ormskirk which is devoid of trees and buildings. Cycled the circuit this morning three times under a clear blue sky and garmin was correct within 15 yards every time – so much better than 99% accurate.
But I have measured a 3.86 mile circuit by calibrated bike which includes trails through pinewoods – eleven runs have produced garmin distance of 3.87 (2), 3.88 (4), 3.89 (3) and 3.90 (2). So 99% garmin accuracy is about right in poorer conditions.
So I guess that runners should not trust their garmins if a course takes in deep canyons, forests and skyscrapers. In general of course, garmins tend to measure over distance and for many reasons. Not least that runners may line up back from the start line and then not run the shortest possible route, especially if they are in the middle of the field.
PS: Many thanks to Old Poster for explaining the grounding of the ship off Blackpool last year.
Bransley runner
running is getting better I am planning to run 1 lap of the Holmfirth 15 race from Holmfirth swimming pool going to watch spen 20