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Attackpoint - performance and training tools for orienteering athletes

Discussion: Attack point proximity

in: Orienteering; Training & Technique

Mar 1, 2013 12:46 AM # 
I was doing some training earlier and a question popped up in my head. I was wondering how close an attackpoint needs to be for it to be effective. Does it depend on the size of the control feature? Are there other factors involved?

Also it would be interesting to get people's general opinions about effective attackpoint use.
Mar 1, 2013 12:57 AM # 
Visibility and angular accuracy are two related factors which would influence how close an attackpoint needs to be. A boulder in a field of thick green bushes requires much more precision than a reentrant on a wide, open hillside because the poor visibility reduces the margin by which you can miss the control and still hit it. Similarly, punching through thick vegetation or a dense network of large boulders increases the error of traveling on a bearing.

I suppose you could summarize these two factors by the effective size of the control feature - the area which you have to enter to see the control - and the propensity to miss given the location. There often aren't a wide range of attackpoint options, so I think you have to be able to adjust given whatever conditions you encounter.
Mar 1, 2013 8:37 AM # 
A loooong time ago, I seem to recall PG saying that 100m is the farthest you would want to go on a precise bearing -- which I interpret as from attackpoint to control. I also interpret it as applying to a flat, featureless area (like much of the NJ Pine Parrens) of moderate visibility.
Mar 1, 2013 2:48 PM # 
I don't think of my attackpoint as something that requires me to use a bearing from there. I think of it as the point where I will have to switch from rough navigation skills to precision navigation skills, thereby slowing down into the control. By this definition, it can sometimes be quite a ways away. The exact distance depends on the technicality of the terrain. The goal is to look for an attackpoint that will minimize the amount of slow, precision navigating that you have to do.
Mar 1, 2013 10:55 PM # 
Wow, a thread about orienteering. And I thought it was going to be something about AP showing who is and isn't online right now.
Mar 17, 2013 2:10 AM # 
I think smittyo spiked it... The attack point is the closest feature to the control that you can navigate to quickly and reliably. From there it is precision navigation to the control. Some legs may not have a suitable attack point at all. Some may have a series. (e.g. Run the trail to the bend (1) - take a bearing - run to the pond (2) - find the outlet stream (3) - bearing and distance to the boulder (control))
Mar 17, 2013 10:31 AM # 
I think one thing I've learnt over the years is to open the vision wider in terms of APs and not ignore easier attack points-(often linked to longer faster track routes) that are BEHIND the control. This also often has the added advantage of aid from fellow competitors leaving the control. MTBO certainly helped me see this point clearly but its equally valid in Foot O.
Mar 17, 2013 12:36 PM # 
Ryan the Lion:
never chosen an attack point in my life

maybe where im going wrong
May 30, 2014 12:27 AM # 
Thanks for all these old threads. Good learning here.
Jun 1, 2014 3:01 AM # 
Greg, attack point (not the name of this site) is something from the era of orienteering when maps where not as good as this days and it still works in some terrain, not saturated with mapped features. Orienteering on elite level no longer uses green, yellow and red light speeds, it is optimum speed all the time. You adjust you speed to the difficulty of the task ahead. If you simplify (and one should not) how Tierry Georgiu approaches his navigation, he is simply moving from one attack point to another attack point in the process of covering the course. You shell train yourself to be able to pick those "easy" to spot features on a map (it could be one or ten on a leg), learn to recognize those features on the terrain. Each terrain and mapping style will present unique set of features, so that is where experience come to play: the more you train on different maps the better you become at this. Also, to make things a little more complicated, the amount of features one shell spot on each leg shell be minimized for maximum speed, yet not to loose reliability. That is where better technical skills will gain you advantage: precise bearing in vegetation, contouring, covered distance control at high speed are just some that pop into mind.
Jun 1, 2014 3:36 AM # 
Whatever the last thing was that you looked for before you looked for the feature that had the control, that was your attack point.
Jun 1, 2014 1:20 PM # 
I agree but also disagree with Balter. Thierry's game is what you need to be a world beating elite, but for those of us who are normal, I think use of the Attack point is one of the most valuable skills an orienteer can possess. I still teach it in combination with simplification. So simplification gets you to pick the 3-10 big features along the way, and this can be done at speed. But then once you hit the final one, your attackpoint, you can switch to a much finer style of orienteering - picking out more detail to direct you confidently into the control.
Jun 3, 2014 11:06 PM # 
"...pick the 3-10 big features..."

Sorry, beginning Orienteer here. But what does that mean?
Jun 4, 2014 12:49 AM # 
Things that stand out in the terrain and are generally unambiguous i.e. different from whatever the map has lots of. If you can link them up on your planned route then you have a simplified period of navigation that is generally quicker as you're more confident and purposeful.
Jun 4, 2014 4:48 AM # 
I think we can refine this red-yellow-green thing.

Concept: you always want to minimize time. Making mistakes costs time, but being precise also costs time. So, you generally want to put minimal effort into precision, but enough effort that you don't risk mistakes that would cost more time (this is race ideal - not training ideal).

Can we write a rough formula for how much it costs you to drift, say, 5-meters off the optimal line. Sure - it's basic trig. If you start 100 m from control and drift 5 m from straight line (say, forming equilateral triangle), you will increase your distance traveled by.... wait for it... just 0.5 meters. However, if you are 10m from the control and drift 5 m off the straight line, then you increase your distance traveled by a whole 4 meters !

Clearly there is more cost to making mistake close to the control, and hence more incentive to slow down and be careful.
Jun 4, 2014 4:51 AM # 
Note, of course, that most real routes include bottlenecks, etc... These are also places where cost of a small deviation is amplified. (Especially common issue in sprint orienteering)
Jun 4, 2014 4:57 AM # 
The precise equation is cost = sqrt(distance^2+delta^2)-distance.

The equation may seem silly, only works in limited cases. But the concept is still relevant to course setters and mappers who are concerned about whether a small map detail significantly effects fairness or whether a control site is usable.

This discussion thread is closed.