Measurement of 'urban' course distances

[Gnitworp]

I quote BOF Rules 2003:
Appendix B: Course Planning
3.6 Measurement of Distance and Height Climb
3.6.1 Course length is measured as defined in rule 6.1.2, and quoted to ± 0.1km (e.g.
5.5km, not 5.50km). This is the shortest route which a competitor could possibly take,
irrespective of whether or not the competitor would be sensible to do so.

I suspect course lengths usually shown on description sheets etc for urban and sprint races are the straight- line measurements, which come automatically when using the OCAD course planning facility. In 'urban' planning the fact that the 'shortest possible route' invariably twists and turns around buildings and out of bounds areas inhibits compliance with the above directive from Appendix B.

Typically the shortest possible route on a leg can be several times as long as the straight-line distance. The best example of this must be a classic leg either side of the Grand Canal in Venice where the shortest possible (dry ) route could be 10 - 20 times the straight-line distance.

This anomalous situation particularly perplexed me when the latest CompassSport course planning competition required us to plan a Sprint Course around the grounds of a Qatari military college that was to be 3km (+/- 200m) in length. I assumed it meant 3 km by the shortest possible route and have submitted a course that is exactly 3.2 km in length so measured, which actually has a straight-line distance of 2.8 km

Should we continue with this 'lazy' practice of quoting the OCAD-generated-straight-line lengths or take the trouble to tell people how long their courses are actually going to be in accordance with the BO Rules?

[DavidJ]

...to plan a Sprint Course around the grounds of a Qatari military college that was to be 3km (+/- 200m) in length. I assumed it meant 3 km by the shortest possible route and have submitted a course that is exactly 3.2 km in length so measured, which actually has a straight-line distance of 2.8 km

So you have managed to get a course that could be either 3km + 200m or 3Km - 200m depending upon the method used to measue it. Complies with the rules which ever way they are supposed to be interpreted - very clever!

[Gnitworp]

[IanD]

Irrespective of how the 'official' course length for control descriptions is calculated, it would be most helpful if the lengths (and climb) people are actually likely to run could be made known at the time of entry - on the flier for pre-entry events; on display at registration for EOD events. Now that we are not obliged to enter by age class, many people want to pick their course based on (actual) length.

This applies to all events, but is particularly relevant for urban events since the straight-line and actual distances can be so different.

[andypat]

Would you do it as an "optimal length"? Or as an expected winning time? For some events like sprint an EWT is the norm. But you have to work out the distance the winner will run to work this out anyway.

[DJM]

The IOF Competition Rules calculate course lengths similarly too:

16.3 The course lengths shall be given as the length of the straight line from the start via the controls to the finish deviating for, and only for, physically impassable obstructions (high fences, lakes, impassable cliffs etc.), prohibited areas and marked routes.

Thinking about this, I doubt that any major IOF Sprint event has ever had its course length measured according to the rule The 2008 WMOC in Portugal had the Sprint lengths as per the Condes straight line measurements for example. But drawing out the zigzag optimal route for some 66 different courses in order to abide by the course length rule might have been a task too far for the poor planners!

[graeme]

EWT is the norm. But you have to work out the distance the winner will run to work this out anyway.

Radical idea, I know, but you could just (get someone to) test run the course

[RCB]

I note that BAOC covered themselves adequately by informing us that the EWT was likely to be in excess of 15 minutes. I doubt however that even they expected winning times of 26 mins+ on some Race 2 courses - That said the fast guys on the longer courses came close to the EWT. Personally, I think it would have been a shame to have missed out on the NEast accom area or the Northern fort at HMS Sultan just to satisfy the 12 - 15 minute guideline.
In respect of Urban racing, I ran in excess of 12km at London last year and I may well have entered a shorter course had the final details/entry form stated the actual (optimum) course distance. I also wonder how many novice orienteers but experienced runners have turned up at an event in the forest and decided that the 3.5k green or 4.0 km red was just too short and found themselves struggling to complete a blue or brown. BAOC normally have a long red of 5k+ at their midweek league events - a good idea.

[Gnitworp]

I note the Guildford flyer quotes 'actual' distances - useful information since they're generally 50% longer than the somewhat academic straight-line distances also quoted.

I think this should be recommended practice for non-sprint urban events. For sprints, distances (especially straight line ones) are irrelevant (misleading) if EWTs are given.

[andypat]

EWT is the norm. But you have to work out the distance the winner will run to work this out anyway.

Radical idea, I know, but you could just (get someone to) test run the course

Duh!
OK - you still have to work out the route the winner would take. I wasnt advocating getting out a ruler. I'm all for EWTs as noted above which should (LAMM on Mull a few years ago excepted) generally provide a better indication of what you should expect from a course.

[roadrunner]

On urban type events, I've always assumed I'd run about 1.5 times the published distance (unless I made any serious mistakes ). If you believe a GPS, not always reliable in these areas:

BKO Parks Challenge, length 6.1km, ran 8.2km
Winchester, length 5.2km, ran 8.9km (but with a serious mistake)
HMS Sultan Race 1, length 2.2km, ran 3.7km
HMS Sultan Race 2, length 2.6km, ran 3.8km

So certainly not perfect, but good enough to determine whether the course is too long or too short, IMHO.

[EddieH]

I had understood - (not been trawling through IOF rules to check) - that urban races are supposed to be measured in a straight line regaardless of real dstance. It may not be accurate but in my view it is unnecessary and unreasonable to ask say the JK sprint planners to measure the shortest feasible route on every course. You always know it will be somewhat more.

In any case there are conventional areas where the actual route taken will be significantly more than the measured distance, yet others where the two will be virtually the same. It's oneof the massive attractionsof the sport for me.

[m4rk]

Maybe for a sprint it doesn't make that much difference and isn't worth worrying about. But in Winchester; length 7.4km (I think), ran about 12km. Its quite a lot further!

[DavidJ]

length 7.4km (I think), ran about 12km.

I make that a factor of 1.6 longer. Seems that roadrunners factor of about 1.5 works for you as well.

[Adventure Racer]

length 7.4km (I think), ran about 12km.

I make that a factor of 1.6 longer. Seems that roadrunners factor of about 1.5 works for you as well.

I generally work on a factor of about 1.609 - which is almost spot on for that