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Attackpoint - performance and training tools for orienteering athletes

Discussion: Small boulders

in: David_Waller; David_Waller > 2016-04-26

May 2, 2016 1:43 AM # 
Sometimes a very small boulder or other micro point feature is still useful for using to be able to place a control at an exact point. For example in a broad reentrant or wide hilltop that by itself would be too vague to use as a control. Of course that depends on reasonable but not excessive visibility in the area - the control bag itself becomes the feature if it is visible from essentially everywhere within the circle but doesn't give itself away from tremendously farther away. Of course that's often not the case and I can share your frustration with the mapping of features that just aren't usable.
May 2, 2016 1:56 AM # 
Thanks, Mike; that's a thoughtful counterpoint. It hadn't occurred to me that these features could provide a helpful control location in an otherwise too vague area. It also makes me think that mapping features that are typically too small by ISOM standards could help competitors keep in touch with their map, even when the features are not used as control locations. Perhaps there is something to be said for mapping such features.

But in the end, I can't really get past the two major annoyances that mapping such features presents: (1) as a course designer sketching-out a potential course on paper, it is pretty important to know the size of the mapped features in order to gauge the viability of each leg. Having a 1 meter minimum standard on point features seems quite sensible. And (2) once 0.2 meter boulders start getting mapped, it is very difficult to keep consistency across the map. At Umstead, for example, there are probably 100 unmapped 0.2 meter boulders for every 1 that is mapped. Inconsistently mapping some arbitrarily small feature causes big problems for course setters and for competitors.
May 2, 2016 2:06 AM # 
Mr Wonderful:
So the map Mike ran on today has wildly overmapped boulders - I believe we paid the mapper per rock.

On my first meet, when I was a wee navigator, I found them terribly not useful as features (for the same....oh crap this is too small), but they were nice for precise positioning in a reentrant or on a spur, even if not designated (keep the larger feature as description). Or sometimes I used them where I'd pick the one next to the one with the rock, then I could easily make sure I was in the one next to the one with the rock, or pace off the rock to help be certain of where in the reentrant it went.

I don't want to introduce logistics nightmares, but younger me longed for a flag setting version with every stone on it, and then a course designing version with only the proper ones on it.
May 2, 2016 2:41 AM # 
One idea - most mappers under-use the possibilities of hidden symbols in OCAD. Create a new text symbol. As you plan courses and note the heights of boulders, write them down. In the map file, type the height of each boulder next to the boulder. Then when you are ready to print maps for courses, just "hide" that particular text symbol. Then the next course planner can turn the symbol on when they plan and off when they print.

I've started using hidden symbols a lot more on some of our newer maps - they are nice for recording the names or numbers of shelters (for when you make a reservation and don't remember the name of the shelter); also for noting the number of parking spaces in parking lots, and other information a planner or director might want. We also have a couple lakes with seasonal variance in levels, and in one map I now have 3 different symbols for lake water and lake borderline - two can be hidden at any given time to reflect current conditions.

By the way MrWonderful, one of those under-mapped boulders proved very useful in relocating today :-)
May 3, 2016 11:57 PM # 
They were small at Peach Mtn but pretty infrequent, most were mapped and there did seem to be a cutoff for too small (even though it was way below 1 m). I think that, like anything on a map (rootstocks, signposts, light standards, park benches), Dave's 2nd point is the most critical. All (consistently selected) if they serve a navigational purpose -- or none.
May 4, 2016 1:29 AM # 
Mr Wonderful:
Somewhere I have a series of pictures where I went and measured three dozen of them, with many in the 20-30 cm range, one I couldn't find, was that day that I decided I should divert my efforts from map updating to promotion.
May 4, 2016 2:13 AM # 
haha Jens. Mike -- I really like the idea of concealing courseplanner-relevant information into the hidden layers of the OCAD file. Heights of point objects, best directions-of-approach, or objects that are too small to meet ISOM specs. During the initial drafting of the map, there is very little extra effort involved in getting this information into the file, and it could be enormously helpful for the course designer. For existing maps, this type of information could just slowly be built-up into the file as different control sites are used. I'm going to start doing this for the Eno River map.
May 5, 2016 12:47 AM # 
We've got a few boulders I have never found on a couple of our maps. Most likely they were just stray pencil marks on the mapper's field notes. But I'm always reluctant to remove a point feature I can't find, especially if I am visiting during summer when vegetation is thick or if I don't have time to do an extensive search.

This discussion thread is closed.