Register | Login
Attackpoint - performance and training tools for orienteering athletes

Discussion: Sprint mapping

in: Orienteering; General

Mar 22, 2006 6:06 PM # 
I decided this leg was too high on the potential bogus meter to include in the team trials course, but I'd still like some feedback.

On the UMSL campus (as with many campuses) there are a set of bleachers that you can run under. In this particular case, there's also a building under there, which makes a somewhat interesting control location. The question is, how to best represent the fact that you can only enter from the sides? Normally, if a "canopy" is closed on a side, you use the "uncrossable wall" symbol on that side. That's a little misleading, since there's really no wall, it's just that the roof is too low to get under. Map clips and a fuller explanation are here (see 3/22).

Has anybody seen bleachers on a sprint map from a WOC or similar high-level event? I'd like to keep my representation consistent with what the elite are doing.
Mar 22, 2006 11:39 PM # 
I believe the solution you show in your second map clip (i.e. heavy black line on the left side) is the best thing to do. You can always apply the CYA test - that is - is it better to just show it as a canopy, with the potential result being a runner approaching from the left thinking they can just run under this canopy to get to the building, but of course finding they can't and have to go around? (and being PO'd because of that) OR is it better to have someone approaching from the left, expecting to see a vertical wall they will have to go around; being a little surprised that it's not really a wall, but having to go around it anyway just like they expected? I think the second scenario is better.

Any orienteer that thinks that the given set of available IOF map symbols (whether for forest or sprint maps) can represent each and every situation in a single definitive way is dreaming. Part of what makes a good orienteer is the experience and ability to be adaptable in knowing how symbols are interpreted. (of course there are limits - it doesn't mean anything goes...)
Mar 23, 2006 6:21 AM # 
If it looked exactly like the webfile I would agree and say definitely go with the 2nd way because with sprint maps it is crucial that it be obvious what is crossable and what it not, especially in complicated areas. You need to give the runner information to help them get to the control and to help them choose the fastest route. An experienced orienteer should know by now that maps lie a bit by only giving you the most important information to orienteer and by modifying things a bit for the clarity of the map.

So, the fact that it is uncrossable is more important than it being a wall. And I think you can definitely argue that it is a wall, it's just at an angle, right.
Mar 23, 2006 1:20 PM # 
I would prefer 1. If the object is a building, part of which has passable canopy, and part of which does not, I would prefer it depicted that way. Then let me make penalty judgements.

This may be at odds with the underlying philosophy of ISOM (not sure about ISSOM), where my take (at least with vegatation), is that it is more important to show penalty than abstract "what it is". Not sure if this analog applies or not, but still prefer 1. Don't put in objects that are not there -- mapping is about information loss from reality to representation, not information change.

Also, note that in ISSOM, if you use the impassable wall symbol, you are making it a disqualification (by rule) to pass. I'm not sure if this is true of the black building symbol. If it is stadium seating, and possible to crawl thru that section, then this may guide your decision -- is it unsafe, immoral, or fattening to pass this section, or do you feel it is ok if people really want to?

Mar 23, 2006 2:35 PM # 
From the ISSOM Forward:

"The most important difference [between ISSOM and ISOM] is that thick black lines indicate barriers/uncrossable features."

The "building outline" symbol is .14mm as opposed to the .07mm "canopy outline", so it qualifies as thicker, but it's certainly less obvious than the .4mm line for uncrossable wall.

The description of 526.1 Building says "Forbidden to pass through or over".

That's the only help you get from the spec, but I believe that the building outline is intended to be butressed by the darker color of the building symbol. Just using the building outline on the canopy symbol does not achieve the same "uncrossable" visual effect when reading on the run. (Contrary to the web clips I posted, it is fairly apparent on the printed page when viewed calmly).

In this case the discussion is pretty academic. The bleachers are in a large field and anybody approaching from the closed side would see it far enough away that they could easily select their route. My real question (still unanswered) is whether the top mappers have reached some agreement on how to represent this. The structure is not uncommon, but the spec leaves its representation unclear.

Mar 23, 2006 3:39 PM # 
At high speed there is no time to distinguish between .07 and .14 mm. Second variant is much better as it gives better perspective of what to expect in terms of passability. I would also mention it in the course setter notes (and possibly illustrate with photo and map section) as this is not standard solution. JMHO
Mar 23, 2006 4:01 PM # 
I've been giving this a little thought as I'm making my first ISSOM map......

Rather than as a "wall", I think the key is to see the heavy line as a barrier symbol. It's not always clear by looking at a map, what is on the ground, untill the feature is in sight. In your 2nd example, it should be instantly obvious what you have tried to show when comparing the map and terrain together, especially with the "tags" on each end of the bleacher.

One thing I think I'd consider doing is adding pillars to the back end of the canopy (bleachers) which might help in the visualization. They would nicely complement the barrier symbol "tags" on the lower part of the bleachers. (Assuming there is actually some kind of post at the back end of the bleachers)
Mar 23, 2006 4:06 PM # 
Well, that's the rub - there are no pillars. The little building supports the structure. Also, ISSOM explicitly warns against representing pillars unless they are pretty substantial. Most bleachers are held up by a lattice of metal beams with no large supporting members. Of course, if this lattice is dense enough that it's hard to run under them, then the whole thing should just be mapped as a building. The canopy symbol implies that you can pass under it with no speed penalty.
Mar 23, 2006 6:35 PM # 
You could make the whole portion of the canopy that is too low to go under black (building) - like the map on the left, but with the left edge noticably thicker. Perhaps even just about 0.4mm thick...

Imagine a regular building with a small canopy area along one edge - and then a larger canopy area along that edge, and so on, and eventually you get roughly to the symbol and effect, of the bleachers...
Apr 3, 2022 2:34 PM # 
Pre-ISSprOM 2019-2, I'd mapped athletic field bleachers with 522 Canopy over-laid with a stairway mode-drawn set of lines generalizing the seating.

What approaches for mapping bleachers that cannot be passed-through are being done under ISSprOM 2019-2? 521 Building is one choice, although bleachers don't have the requisite roof and I think that would be highly misleading, visually.

Keeping with 522 Canopy over-laid with a stairway mode-drawn set of lines, confessing to a deviation, and adding a note that they cannot be passed through (assuming true for all bleachers on the map...) would seem to be the most useful and appropriate option. This is fairly safe, too, as all or most of the bleachers in my current case back up against uncross-able fence, so there's no reason to consider passing through bleachers, anyway.

Apr 3, 2022 2:53 PM # 
Do you have a picture of said bleachers? For standard fairly small bleachers I tend to use a staircase symbol of the appropriate width with an impassable wall around the back to show you xanr get up from that side.
Apr 3, 2022 8:12 PM # 
Sorry, I've not found any on-the-ground pics in my collection. They vary in width from abt 7m up to about 22m, otherwise very standard school grounds-type bleachers. I like your suggestion, although it might be faster for me to draw them with stairway mode than to modify the stairway symbol. Good idea on the impassable symbol where necessary. Thank you.
Apr 3, 2022 9:56 PM # 
I'm with Canadian on that one, whether impassable fence or wall. I found that most places with such bleachers are not suitable for going underneath either, are surrounded on 3 sides and are not a canopy "through way". And even if there was a way of running through underneath the bleachers, most school campuses that I have mapped had that area underneath for storage purposes and would have wanted it out of bounce. Even though there is no true wall there, it does at least give an idea on which side the stairs are accessible from.
Similar to the guidelines of mapping an area under a canopy with 3 walls and one open side as building, bleachers would thus be stairs onto an area under a canopy with 3 walls, thus stairs onto a building or onto an out-of-bounds area., scroll down for the Guidelines, bike storage closed on three sides on page 15.
Apr 4, 2022 7:41 AM # 
Where will the school kids make out if under the bleachers are OOB?
Apr 4, 2022 8:15 AM # 
A photo would be good, as I can't open the link in the original post. 'Bleachers' is not a common term outside of north America I would think, so it took me a while to work out what you were all talking about! Do your pants turn white if you sit there?

It's worth referring to WOC sprint mapper Kjell Sonnichsen's sprint mapping page, especially scroll down to 'what not to include'. I would certainly not map a small stand of seats, except possibly with an X, and for larger ones I think I would just use the canopy symbol with it's normal boundary and let the runners work out if/where they can enter it.
Apr 4, 2022 9:42 AM # 
Tricky, they are OOB to orienteers precisely so that the kids can make out in peace. Simmo - if you don't know what bleachers are you need to watch more American high school TV dramas.

That mapping page by Kell is interesting and very useful - and he deserves a lot of credit for writing it. But I think it needs a bit of a warning - it is just one person's ideas - not a definitive 'official' view. I have always found the way he maps individual trees (green circle or dot + white) as unusual (and to be honest weird). When there is discussion on that topic on Orienteering Mappers International opinions differ but I would say the consensus is that adding the white halo is generally considered to be not 'correct'.

In the 'What not to map' section - I find the suggestion not to map those stairs remarkable. In the explanation he says the stairs are 'Very prominent' then says he would not map them. Being 'very prominent' is pretty much the definition of why something needs to be on the map. I can't imagine leaving stairs like those off the map.

These days a better resource is the GUIDELINES FOR MAPPING AND COURSE PLANNING IN COMPLEX URBAN STRUCTURES ON SPRINT ORIENTEERING MAPS! which was recently released by the IOF Mapping Committee - coming from the MC you can assume that is an 'official' view - not just one mapper's opinion. Also worth looking at is the newly started Mapping Wiki - it is overseen by the IOF mapping committee - so again it should be fairly definitive - not just the views of individuals. Perhaps some of you on this thread could contribute photos and map samples of 'bleachers'

Also Kell's page is out of date - ISSprOM has been updated since that was written - for example the green dot for bushes/small trees now has a small white hole.
Apr 4, 2022 11:29 AM # 
Apparently the etymology of "bleachers" is that the boards get bleached by the sun, so I guess you would as well if you sat on the long enough.

One of the weird things about AttackPoint is the "how do I map this strange thing?" discussions where somebody is just overthinking something. Yeah, technically you could get under the bleachers, but who cares? They're just wide stairs going up to nowhere.
Apr 4, 2022 11:51 AM # 
I must admit I've taken to mapping trees with varying 'haloes' of white if they appear as the example on Kjell's page but this is rare. If you're going to be impaired running under it, then I think something in addition to the tree symbol should be mapped there. I don't however like what I've seen on some sprint maps where every tree has the white halo (or there's not even a tree mapped and instead just the white for the canopy).

We had a recent 'sprint' relay (our map was 1:7500 so doesn't really count but I also saw the 1:4000 version that the regular public entrants were given) where a tree was mapped next to two thickets as a tree but all I saw when I got there were three thickets and got confused. Apparently there was a tree in the thicket but I didn't see it because of the thicket. It cost me and others some time. From my understanding it was mapped as a tree, then someone (the setter?) asked for it to be changed to a thicket because that's what the runner sees but somewhere along the way it got changed back to a tree.
Apr 4, 2022 12:18 PM # 
Examples of the white halo would be pretty rare in Western Australia, where in urban sprint areas either eucalypts or deciduous exotics tend to dominate, and landscapers like to clear the lower branches of exotics, while eucalypts mostly have naturally tall trunks. But I would say it is a valid solution for the examples shown by Kjell Soennichsen.

I acknowledge that Kjell's last update was before the recent ISSproM changes, but no doubt with WOC in Denmark again this year he will update again - which I am looking forward to. The new IOF documents don't really address many of the issues raised by Kjell, and this is why interpretations such as his are necessary.

Regarding the stairs, I mostly agree with Kjell. If you tried to map them at the ISSproM specs they would take up too much space and make the map harder to read. Runners at speed will just ignore them anyway because they don't lead anywhere, and surely only a novice course setter would contemplate putting a control on them.
Apr 4, 2022 12:22 PM # 
I seem to recall that a grandstand area was mapped at the 2009 WMOC sprint final at Sydney Olympic Park, but I've forgotten how.

One interesting use of pillars I've seen was in Singapore. Typical high-rise apartment towers in Singapore are largely open on the ground floor (I guess to assist airflow). I got to the map and wondered "where are all these big buildings on the map?" before I realised that they were mapped mostly as canopies with the pillars, elevator shafts etc. mapped as small buildings.
Apr 4, 2022 1:01 PM # 
I make a lot of maps of high schools in Florida. There are hardly any that do not have a sports field with at least two grandstands.
A special symbol was necessary to show the grandstands. I wish I could show it here but I can't so I'll explain:
Copied the 520.002 Area that shall not be entered symbol
Changed border to 522.001 canopy outline to get a thinner border
Changed hatch line width and distance to .1 mm and .25 mm respectively.
Use direction of area arrow to orient the 'stands' correctly
Still experimenting with best symbol for background.
What about passing underneath? runnability? These areas are almost always fenced off but from what feedback I have received the schools like the symbol. and if they can use the grandstand it is the corners where the controls go.

But Canadian how about showing that map of Lansdowne Park? We were sprint orienteering in and through the south side stands, weren't we?
Apr 4, 2022 2:11 PM # 
[the stairs] don't lead anywhere

What has that got to do with anything? Dead-end roads " don't lead anywhere" but we still map them because they are prominent and not mapping them would be confusing. The stairs are very prominent so should be mapped.

Interestingly on the map he has mapped hedges but not the stairs. Why are those hedges even mapped? . By the same same logic involved in the statement about the stairs ("they don't lead anywhere") the hedges should not be mapped because the only reason to map them is to show an impassable barrier - which is redundant due to the building. It seems like he has mapped them because he judges them to be "prominent". But when I look at the photo I barely notice the hedges - however I certainly notice the stairs!. The decision to not map the stairs results in this counter intuitive mapping - mapping the less prominent feature and leaving off by far the most prominent feature.

There is no reason why those stairs cannot be mapped clearly without causing clutter on the map. You just need to take a bit of extra care with the drawing.

Apr 4, 2022 3:38 PM # 
Many of the highrises in Singapore are built on "stilts", thus having no ground level apartments that could be affected by flash flooding. Singapore has pretty much daily rainfall, even when it's not rainy season. Those areas are also nice outdoor places to hang out near the neighborhood playgrounds when a downpour occurs, and one can get out of the way of lightning, where Singapore is the lightning capital of the world.
Apr 4, 2022 4:49 PM # 
I was about to wonder if gordhun would challenge that claim because central Florida is the real lightning capital, but I looked it up, and Florida only holds the title in the US. The worldwide record holder turns out to be Lake Maracaibo, Venezuela.
Apr 5, 2022 2:11 AM # 
Regarding steps that go nowhere, I mapped those steps also. They represent an obstacle that has to be run around so increase distance. I have also used them for control locations as they are convenient feature to tie a control and better than saying side of building.

For the grandstand/bleachers, my local University (and High School) American Football stadium has a large grandstand that can be run under. While I think the technically correct answer is to map it a dual level area, I opted for the canopy symbol with thin black lines to represent steps. The bottom area is usually closed/fenced in so not likely to be in play but is clearly visible. In previous years someone did hang a control in the seating section of the stands which was neat running in the stadium. The other sporting event seating areas are all inset into hills so I used the paved symbol and if the contours didn't show it I added in the thin black lines again to show the steps. No experience on small grandstands used by fields and tennis courts that exist on a sprint map (I left them off on my non sprint maps as they do move)
Apr 5, 2022 6:15 AM # 
Regarding comments on trees with white halos - in the Sprint Specifications the large tree symbol (417) has a white halo/mask (e.g. so it stands out in yellow and green) and a white centre. The small tree symbol (418) has a white centre/dot as Rob says above. This is for colour blind orienteers to distinguish it from the brown dot (Mound). The green cross for a prominent vegetation feature (419) also has a white mask.
Apr 5, 2022 7:10 AM # 
This is a bigger halo, used to indicate canopy. Hand drawn, not part of the spec.
Apr 5, 2022 8:18 AM # 
the etymology of "bleachers" is that the boards get bleached by the sun,
Ah, I always wondered why we don't call them that in Scotland.
Apr 5, 2022 8:25 AM # 
We call them grandstands because you sit down on them.
Apr 5, 2022 9:54 AM # 
Same here. Grandma and granddad never though it was fair..
Apr 5, 2022 2:15 PM # 
Of course, nothing but pure clarity from the land where we park on the driveway and drive on the parkway... ;-)
Apr 5, 2022 9:12 PM # 
What the heck is a parkway?
Apr 5, 2022 9:53 PM # 
Uncle JiM:

Please login to add a message.