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Attackpoint - performance and training tools for orienteering athletes

Discussion: Thoughts on when we begin O again?

in: Orienteering; General

Apr 28, 2020 12:35 AM # 
Apr 28, 2020 12:36 AM # 
Asking for a friend of mine :-)
Apr 28, 2020 1:33 AM # 
Your thoughts first?
Apr 28, 2020 3:21 AM # 
Depends on what you mean. If you mean running with a map, some folks have been creative enough to have kept it up with reasonable distancing. If you mean traveling across the country and crowding around some large screen displays with sun reflecting off them and squinting to try to see how everyone did that day, I think that could be a while yet.

The question I've wondered recently is what is this doing to OUSA finances? There isn't going to be much head tax going in with NRE's all cancelled/postponed, and clubs replacing local meets with run-on-your-own-schedule maps posted online with no "starts" or entry fees. Presumably there are still expenses for insurance and the recently hired staff? But are club charter fees enough to cover this?
Apr 28, 2020 3:53 AM # 
Fossil is bang on. Last year for example Suncoast Orienteering turned over more than $4000 to O-USA. So far for 2020 we owe about $800. I see some doubt that we will get even $800 more in the last part of 2020.
I don't know whether O-USA pays a flat rate or per start to the insurer but if it the former then some serious renegotiation has to take place.
Then the amateur sports organizations have to get together and make their case. The governments put them out of business; the governments have to help them out.
Apr 28, 2020 4:03 AM # 
Well in Chicago we have some IOrienteering courses set up, but locked out of Cook county (Chicago) forest preserves for that type of event.
In Wisconsin we set up an IOrienteering course and the state parks closed 4 days later.
Yes going to be hard for OUSA to get their revenues.
So when do you think the local and national meets is the real question. So a while yet??
Apr 28, 2020 3:41 PM # 
We in the sanctioning committee somewhat optimistically sanctioned EMPO's one-day NRE on October 3. The Rocky Mountain Orienteering Festival (beginning of September) hasn't officially been cancelled yet, I believe, but I am doubtful whether it will happen...
Apr 28, 2020 4:31 PM # 
I can see some fall events happening with a limited number of participants from a limited geographic area. At least, we should prepare ourselves for the idea.
Apr 28, 2020 4:43 PM # 
Once traveling large distances is considered a safe and responsible thing to do again, I'm going to start organizing trainings with GPS punching.

So there's some O there.
Apr 28, 2020 7:02 PM # 
At this point, my club is still planning to re-start local events in June, and is working on some social distancing guidelines which include:
Online pre-registration only. No on-site registration, check in, or payment.
You must pre-register for course, amd for a particular 10 minute arrival and start time. We plan to limit registration to 10 people per 10 minute block (both numbers could change).
Maps will be pre-bagged with your name on the bag; just pick up and go. Rental SI card in the bag if needed.
Any course changes or any second runs communicated to computer operator by text message.
Download statiion and printer will be sanitized periodically, extension cables to increase distance between computer operator and the download printer. Possible plexiglass screen for computer operator or have him or her work from inside a vehicle. Queueing area for download marked at 6-8 foot intervals. No results display screen.
No water controls / water stations in forest. BYO water.
Individual water bottles or poured cups at finish, if water is offered at all, probably no snacks at finish; if any are offered they will be individually packaged.
Returned SI cards will be washed / sanitized.
Apr 28, 2020 7:35 PM # 
Nice ideas Mike!
Apr 29, 2020 1:25 AM # 
So, what do you think is the likelihood that water stops on courses are a thing of the past in the USA? (I've been meaning to ask this for a while now.)
Apr 29, 2020 2:36 AM # 
In its current ugly form it should not continue regardless of virus
Apr 29, 2020 3:31 AM # 
Quite frankly, if Mike's measures are what are needed in order to have regular events, from both an organizer and participant point-of-view, I would prefer to stick with virtual / "non-event" (eg, "ParkQuest" by OCIN) O-ing.
Apr 29, 2020 1:02 PM # 
The point that yurets is making is what I'm referring to. Current OUSA rules require that the water be presented in a manner that it is not practical to drink from the jugs. The onus here is on the organizer, not the participant. This can be achieved by either having someone pouring drinks (which is done very occasionally), or by using containers that you can't really drink from directly (e.g. large "Gatorade" containers, or the smaller disposable containers with a similar tap), although it's often been described as the "chain down the jugs" rule.

Typically, though, the easiest approach has been used, that being gallon jugs and a bag of paper cups. Anybody who is concerned about the risks obviously has the option of bringing their own water -- I know of several people who do this, though probably for other reasons (they want water whenever they feel the need, not when they happen to get to a water stop).

This issue came up once before and I got read the riot act for suggesting that we could forgo supplying water, that it was a basic safety issue and we'd be putting people at risk if we didn't do it. I disagreed, and said I felt it was a courtesy. If the current situation has brought the issue to the forefront, would it make sense to tell people that it's their responsibility to carry their own water?

The alternatives would still involve people handling objects that others have handled, and I don't know how long the current paranoia about that will continue. I have no idea whether any disease has ever been transmitted at a water stop at a US orienteering meet, though I don't consider it all that likely. (As a matter of full disclosure, I will point out that when I was younger and in more of a hurry, I would often drink at a water stop without using a cup, but I never put the jug to my mouth. I used to pour the water into my mouth from six inches away, which I'll argue presents less risk than using cups, though others might disagree.)
Apr 29, 2020 1:08 PM # 
Think the plexiglas for the download is a good addition Mike - the number of times I've been breathed on and sweated on on download. I would be tempted to tell people to get changed and wash before downloading too, but then you risk them leaving without having done so. Unless the download is on the route driving out of the parking lot...
Apr 29, 2020 1:08 PM # 
At the Scottish 6-Day with thousands of competitors, the organizers do not provide any water on the course or at the start/finish. Granted, it's not the litigious United States, but if they can hold events like that so can we.

Is it time to petition the OUSA Rules Committee to make the change?
Apr 29, 2020 1:10 PM # 
It's also a lot cooler in Scotland! They removed water for plastic waste reasons but it works very well in these COVID days too.

Does it really take a petition? If so it should be done!
Apr 29, 2020 1:44 PM # 
Florida is another orienteering jurisdiction that does not supply water on courses. It is expected that participants will carry their own and most do.
I do not think this policy was decided for any health reason but if it works... sure.
Apr 29, 2020 2:59 PM # 
I think it's a matter of time before many (most) events stop having results display screens, and just provide results via a webpage, with local wifi so that people can read them on their own phones. Larger championships may still have screens for a leaderboard or something.

A longer cable to the download box is probably at least as effective as a plexiglas shield. And just put the box very close to the finish line punch, if possible, so that people download before they have a change to get away.
Apr 29, 2020 7:41 PM # 
Don't forget to also leave clear and check bricks near the download brick so the occasional person will get it wrong and end their run in tears. It's the only way to teach people to check brick numbers!
Apr 29, 2020 9:47 PM # 
tRicky, you won't believe it --- this is what they do here all the time! How did you know???
Moreover, a typical friendly-face volunteer can get VERY annoyed if you try to double-check before inserting the chip in one of 2 or 3 unlabelled readers.
Apr 30, 2020 7:19 AM # 
Terje Mathisen:
We've had a bunch of local events in Oslo over the last month,I organized one of them which has been sort of typical: The courses are open from April 21st until May 3rd, the map is published as a PDF plus there's a bag of maps on the start for people who don't have access to a color printer.
Voluntary registration fee of 30 NOK ($3), sent via phone payment.
Self-timed or via Livelox, everyone who has either paid the registration fee, uploaded to livelox or sent me an email with course/time gets on the regularly updated result list.
So far I have nearly 75 registered runners (50 of them with GPS tracks) so an average of 10/day: No risk of people bunching up!
BTW, in order to allow a single map to be used for all three courses, I created a Long course which had 3 butterfly loops of very varying lengths, then the Medium course was told to skip the first loop and the Short course would skip the second (longest) loop.
At any given day I have at least 3-4 such courses/events to chose from, unfortunately I started Cov-19 isolation by falling on a run with my son, fracturing multiple ribs. Now, after 5.5 weeks it is still too painful to run. :-(
Apr 30, 2020 7:35 AM # 
unfortunately I started Cov-19 isolation by falling on a run

You are probably one of a very few people who thinks it's unfortunate to injure yourself during a lockdown. With no events on and some countries banning even going outside, it's the best time to get injured!
Apr 30, 2020 7:40 AM # 
Get well soon Terje! I did 5 ribs last year:-) It doesn't seem to have affected your typing fingers though...
Apr 30, 2020 7:51 AM # 
It's worth noting that Norway, probably more than any other country I know of, has actively encouraged (individual) outdoor activities during the recent period. The outcomes in Norway relative to most other European countries suggest they might have the right idea.

(There have been studies coming out of China, at least, that suggest that outdoor transmission is almost non-existent, although as with many preprints emerging on the subject, it's probably as well to wait for the findings to be replicated elsewhere before getting too excited).
Apr 30, 2020 1:31 PM # 
I agree with Guy. We don't need all that rigamarole. If we are so concerned with people coming into contact, then just put the map online and if people want to compare their splits, they could upload them to AP. Also: people could choose their metro conditions in order to make the course easier or more difficult. They could do it as a NightO or choose to do it in the middle of a thunderstorm.
Apr 30, 2020 1:50 PM # 
Terje Mathisen:
@tRicky: You are right! I have definitely consoled myself with the thought that now I'm not missing out on an entire spring series of competitions. I have done several MTBO trainings but nothjng serious.
Re. degrees of lockdown in various countries: We were definitely caught somewhat flat-footed when more than 500 people returned from Italy and Austria where they had taken their winter break doing alpine skiing, and then catching Cov-19 during the evening partying. When all of them returned to their various communities they provided a strong starting point for the virus spread, particularly since it took an extra week or two before our CDC-equivalent to recognize that not just Italy but also the Austrian alps was a hot spot. Anyway, since we closed down on March 12/13, statistics show that we've been surprisingly good about following recommendations, limiting the spreading factor to about 0.7 even though family/sub-5 people groups have been encouraged to hike/bike/run as long as everyone stay at least 2m apart.
Orienteering to fixed controls was recognized very early as a perfect activity, so we've sold more map envelopes from Stifinner'n (from Nydalens SK) and all the other clubs who do the same. This avoids the problem when everyone would otherwise go hiking on the same 2-3 trails from the Sognsvann parking lot.
Apr 30, 2020 3:36 PM # 
Agree it might be time to eliminate organizer-provided water stops. And maybe porta potties, too? And maybe switch to SI Air where that hasn't already happened. Though I'm curious to know more about "GPS Punching". Does that mean downloading the gps track from your watch or does it require carrying a phone with you on-course?

The print-your-own-map, run-on-your-own-schedule meets are filling the void for now, for those who still have access to their maps and are within a reasonable driving distance. That's unfortunately not everyone. And they don't easily facilitate teaching beginners. This is unfortunate since this might otherwise be a growth opportunity when people are looking for safe things to do outside and unable to participate in their 1st choice activities.

I do wonder still, what the budget situation is looking like for OUSA. Maybe that should be a separate thread. Or maybe those in the know aren't ready to release data. But if it's dire I'm wondering if maybe we should try something creative. Like setting up a crowdfunding type thing where one could, e.g. submit a voluntary donation each time they run at one of these free on-your-own courses that would otherwise have generated a head tax or start fee. (Note: only suggested for people not unexpectedly out of work)
Apr 30, 2020 4:35 PM # 
If normal epunching presents an unacceptable risk of spreading disease, then we're screwed, and I give up.
Apr 30, 2020 6:42 PM # 
Terje Mathisen:
@jjcote: Please don't give up!

Yes, punching with regular EMIT will probably be off limits for quite a while, simply because there is no way to avoid touching the control unit with several fingers while trying to punch quickly, and sweaty orienteers are sure to both deposit and pick up moisture from the shared surface.

SI _might_ be a bit safer simply because of much smaller contact surface, and at least the possibility of punching without touching anything with either the stub or your fingers, but touchfree is the way to go.

This means EMIT or SI radio tags for serious/championship level races, the honor system (run within a meter of all flags, but without touching them) possibly augmented with live GPS tracking or personal watch/cell phone track logs for everything else.

Bringing your own water is a no-brainer, if safety is a concern then you simply require a signed waiver and/or a pre-start check that each competitor is carrying at least x dl of water/sports drink.
Apr 30, 2020 7:43 PM # 
I'm with J-J. I think it's incorrect to assume that we need to eliminate absolutely all risk of infection, no matter how small, in order to hold an event.

IMHO we shouldn't be holding actual events until the catchment area for the event has very few cases, lots of testing, functional contact tracing, and people are quarantining appropriately. When that happens you can hold an event and assume that with reasonable precautions (e.g., keep things outside, protect workers from prolonged close conversation, have a tippy tap at the finish, etc.) your event will not be the source of a new outbreak. That's it. If you believe that one infection = failure then don't hold an event, just do BYOM stuff.

I guess NZ and AUS can start and tell us how it goes :)
Apr 30, 2020 8:02 PM # 
I'm the OUSA VP Finance, and I'm looking closely into how COVID-19 will affect OUSA finances. The highlights are:

1. OUSA takes in the bulk of its revenue (about 2/3) in January from club dues (45%) and membership dues (20%). Club dues reflect activity from the previous year. In some sense, club activities in year n then fund expenditures in year n+1. OUSA currently is well-positioned to weather the pandemic without dramatic impact on programming.

2. While income for 2020 (to be received in January 2021) will go down significantly, especially sanctioning fees and club dues, which constitute about 60% of OUSA's operating budget, some operating expenses will also be lower. We may be receiving a partial refund on our insurance premiums. None of the teams are traveling to competitions, so that funding can be moved to 2021.

3. Since the end of 2016, when OUSA's unrestricted funds briefly dipped below 0, OUSA has pursued a very conservative fiscal policy. OUSA's reserve policy as of 2017 has been to maintain an operating reserve sufficient to cover all restricted commitments, board-designated commitments, and at least 25% of unrestricted expenditures from the previous year.

Edit: the relatively stable financial position of OUSA is due to the efforts of several people who have been involved in OUSA finances, especially Pat Meehan and Barb Bryant.

I'm looking into this more extensively now, but OUSA should be ok. I'll have a more extensive update at our next board meeting, which is currently scheduled for June 1.
Apr 30, 2020 8:35 PM # 
@iansmith (or Clare), will we ever see any meeting minutes from this year?
Apr 30, 2020 8:43 PM # 
Ian: JWOC and WOC may be held in the fall of this year, in which case there will be Team travel expenses.
Apr 30, 2020 9:19 PM # 
@JanetT, I don't know why Ellen hasn't been posting them in the minutes folder. Thanks for the reminder; I'll check with her.

@peggyd - Good point.
May 1, 2020 2:01 AM # 
I don't know how everyone else uses SI bricks but I can quite easily record my punch there without touching the brick. SI Air is obviously easier though I notice people seem to touch those more than the regular bricks!
May 1, 2020 9:08 AM # 
Right, and we're not talking about a surface where one person touches it, and then another person touches it, like a door handle. This is person to surface to surface to surface to person. The minimal contact between the stick and the box when someone punches seems really unlikely to be a signifcant transfer of pathogens. And as tRicky points out, what I've seen of SI Air typically has people clapping their hand down onto the box. There are so many other occasions in daily life that present a bigger risk.
May 1, 2020 11:39 AM # 
Sounds like maybe you're confusing SI Air (wave stick at box from a foot away) with those combo compass/SI punch devises that require you to center the compass on top of the SI box.

Regardless I don't believe standard SI punching is necessarily as touch-free as you're making it out. What you describe is certainly what I do, but everyone has their own routine. With a different grip one could easily have the heel of their hand contact every box. And watching video from some of those major European relays I recall seeing many people approach the control and rest their non-punching hand on either the box or the support the box is mounted on.

It's time to just go touch-free, whether that's SI Air or maybe this "GPS punching" that was mentioned earlier. Are there details somewhere on what that looks like?
May 1, 2020 12:06 PM # 
" I think it's an exaggeration to think that one infected person at an orienteering meet would be likely to infect many others," It is hard to believe that it is less than two months since this was written.
May 1, 2020 12:07 PM # 
Nope, when I've seen people using SI Air in Europe, they could just wave the stick at the box, but they actually tag the box with the hand that has the punch in it. Maybe not everybody, but a lot of them. And it's what I did when we used SI Air at the Team Triels one year. The place where SI Air gets used consistently in the "wave at the box" manner is the place it was designed for, places where the other equipment makes normal epunching awkward (Ski-O and MTBO).

If we're at the point where were afraid of touching anything that's been touched by something touched by a stranger, then I give up. Everything in life has become impractical.

For GPS punching, take a look at
May 1, 2020 12:13 PM # 
jjcote is correct, I see it in Aus all the time. Competitors whacking the SI box with their SIAC 'just to be sure'.
May 1, 2020 12:19 PM # 
By the way, the line quoted above was written by me and crossed out along with the rest of the post within a couple of hours. That said, although we went to a scenario where everything has been cancelled, I continue to feel that orienteering is something that presents very low risk. Holding meets during a shutdown is obviously something that wasn't going to happen, but in the imaginary case where it would, it's my opinion that it could in theory be done without people interacting in any significant way, without much change in the way we normally do things. Skip the results board, don't hang around near anybody at the start or finish, and you're basically done. Would I be concerned about going to an orienteering meet in the current situation? No, not really. In a situation where other activities are happening, I just can't see that orienteering is a risky one. Compared to, say, being in any kind of audience for anything, unless it's on TV. Or using any form of public transportation.
May 1, 2020 12:40 PM # 
Well, we've got a restart happening somewhere in the world - there's an event happening in Darwin on Sunday. (The Northern Territory hasn't had a new case for weeks, and is consequently opening up well ahead of the rest of the country).

If you're thinking of going, you can't (unless you're already there) - anyone entering the NT, including from other parts of Australia, currently has to spend 14 days in quarantine.

I'm hopeful, if things continue on their present track (which is very different to what the US and UK currently face), that local events will be able to resume in some form in other parts of Australia in a few weeks.
May 1, 2020 1:13 PM # 
The temptation to fly to Australia is somewhat higher than usual at the moment for expatriate citizens...
May 1, 2020 1:46 PM # 
feet>>Take me with you as luggage.
May 1, 2020 1:49 PM # 
You are Inara's luggage in life, not mine.
May 1, 2020 2:54 PM # 
Terje Mathisen:
I'm somewhat surprised to hear that SI Air users tend to "whack" the stand, with the Emit touchfree system the tags are both quite sensitive, and contain a very bright led that blinks for 5 seconds when you punch.

I can't recall ever having touched the control stand, I just pass my hand over it at full running speed. I have mispunched just once so I had to turn back, but that was on a ski-O event where I passed the control going downhill at speed and my ski poles made it harder to position my hand to pass close enough, particularly since the stand was on the right-hand side and I had the tag on my left hand. :-)
May 1, 2020 4:52 PM # 
If we're at the point where were afraid of touching anything that's been touched by something touched by a stranger

I don't think anybody expressed concern about transmission from hand->object->object->hand.

But we know that numerous sweaty people are touching the boxes directly, as well as the stands that the boxes are mounted on. Look just e.g. at a day in the life of a finish line punch and stand.

You argue on the one hand that stick-in-the-hole SI punching will be fine, but then on the other hand that SI Air punching won't be? How about putting an electrified cage around the air boxes? ;-)

I had an incident once when I had to punch stick-in-the-hole with an air punch on an MTBO course using air punching after I rode too close to the finish box when I passed by it in the middle of the course and it turned off my air punch. Lesson learned there.

The usynligo setup sounds interesting. I'm not crazy about having to carry a phone on-course, at least without having a second one just for that use. I guess that's possible but not sure if it will scale for everyone who wants to O.
May 1, 2020 5:03 PM # 
Ian, thanks for the finance summary. The picture sounds far better than expected.
May 1, 2020 8:03 PM # 
Sounds like WA is going to further "relax" measures from next Friday also. What that entails is anyone's guess though I doubt it'd involve restarting any sporting events (I'm sure AFL would get very upset if they weren't the first sport to restart). Plus OWA would need a bit of lead time to get anything up and running since we've cancelled everything up until at least the start of June.
May 2, 2020 12:25 AM # 
I'm not saying that SIAC is worse, just that for many people it's the same.

And if people touch an SI box, I dont care, I'm only putting my punch in the hole. If other people put their infected punches in the hole first, well, that's a multi-surface transmission route.

I don't think sweat is an issue, by the way. I haven't heard anything about the virus being transmitted through sweat. It's people wiping their noses with their hands that you probably want to consider.
May 2, 2020 1:25 AM # 
Can we change the requirement for having water on the course to having a hand-washing station at the finish/assembly? A lot easier on the course setter and pretty helpful. The CDC even has a how-to guide.

If everyone can wash their hands and the meet workers can keep distance, then all we're missing is a way for people to be able to animatedly discuss what was wrong with the map at point x without having to stand really close to anybody else.
May 2, 2020 2:20 AM # 
Should we start practicing those discussions over zoom?
May 2, 2020 2:36 AM # 
Backstreet Boy:
To me the question is, would a "socially distant" orienteering event be riskier than a trip to the grocery store? Each product you pick up is a control, and the cashier is the download station.
May 2, 2020 3:45 AM # 
I think its probably a decade since discussion here about GPS punching heh heh.

usynligo is but one of a number. Search also for MapRun (sometimes called Maprunners), Sporteering and iOrienteering. I'm sure there are others - please chip in. I wonder which is (or are) going to emerge as the de facto standard. Maybe there will be a spinoff from the development of contact tracing.

Carrying a phone a barrier? I think the convergence of phone-camera-GPS-making the toast technology will deliver wearable solutions.

PS If there's any orienteering map still not geo-referenced, lockdown is a good time to work on it:-))
May 2, 2020 4:14 AM # 
Sweden is hosting small local events under 50 people . are they doing?
May 2, 2020 6:58 AM # 
Our local area (100 km south of Stockholm) has 4 clubs. We take turns putting on training races with SI. Only pre-registration and no services of any kind at the event. Approx 100 participants spread out on a start list between 9:30 and 12. We talk to each other without standing too close together. Livelox to compare routes online after. Certainly feels like lower risk than going to the grocery store.

Our club also keep our weekly training schedule and junior programs going. We only meet outside, keep the groups small, keep some distance to each other, strictly no one shows up with any slightest symptoms of anything.

We also build up a library of training maps where people design courses, hang ribbons and post PDFs for download.
May 2, 2020 1:05 PM # 
The latest version is called MapRunf. Ran a course a couple of days ago with it. Its not SIAir speed punching, but its good enough.
May 2, 2020 2:00 PM # 
if people touch an SI box, I dont care

Sorry to keep picking on you, J-J, but the point of the discussion is how to get the sport going again in a format beyond BYOM large time window on-your-own-schedule and back to something that resembles a traditional meet. If numerous people, sweaty or not, are touching the same boxes or the stands the boxes are on with their hands, then we have cause for concern. And likely so will the liability insurance carrier.

The fact that many of us never touch any of the SI equipment other than our personal stick doesn't solve the problem that many people do put their hands all over them.

I happen to be one of the people who has allergies and yeah, some days it seems like I'm constantly wiping my nose with my hand or my sleeve when I'm running. I don't touch the boxes but can we assume that for everyone who has allergies?

On the GPS punching topic, having something in a watch format would be a big plus. My concern with carrying a phone isn't as much about having to carry yet another piece of equipment as it is the risk of damage. I need my phone to do my job. Less so for conversations than for a couple of key security apps that are on it. Inadvertently breaking it on the weekend would be a problem. If GPS punching is possible with the phone in a hard-shell case in a fanny pack then that could work. Otherwise I need a 2nd phone for orienteering. But if I have a GPS watch on my wrist that talks bluetooth to my phone then maybe there's a solution somewhere in there.

Looking further out... maybe requiring participants to carry a device with a screen would actually help draw new people into the sport???
May 2, 2020 2:29 PM # 
Burner phones appear to cost $25-$40. I'm not sure how this all works, but I think you don't need service of any sort for this to work. The phone has GPS and can run an app, and can upload afterwards via wifi. I have an old phone (wasn't compatible with my new car because it was running too old a version of Android and wasn't upgradable), and it works fine in my house to stream a radio station and send the audio to a bluetooth speaker, even though I can't make calls or use it for mobile data. That should work, for something like UsynligO, right?

On the sweat issue, I'm not disagreeing, I'm clarifying. Sweat has nothing to do with it. "Everybody" touches their nose while they orienteer. Some people then touch the box with that hand. If other people also touch the box, that's the issue. But you don't have to touch the box to put your SI in the hole. How does this compare with the handle on the freezer case in the supermarket or the gas pump? If we're assuming that we'll be getting back to life where people aren't wearing gloves for normal everyday activities, then I don't see that epunching will present an unreasonable risk. Maybe we won't get back to that point?
May 2, 2020 2:35 PM # 
Incidentally, regarding rental SI sticks, I believe Valerie has been running them through the dishwasher for years, long before this came up.
May 2, 2020 2:45 PM # 
I happen to be one of the people who has allergies and yeah, some days it seems like I'm constantly wiping my nose with my hand or my sleeve when I'm running. I don't touch the boxes but can we assume that for everyone who has allergies?

Sounds like typical symptoms of allergy to orienteering
May 2, 2020 2:46 PM # 
Re SIAC, organisers usually set the boxes to have a fairly small range for foot events, but up to 5 metres is available and could be used in present circumstances. The thing is though, that competitors need to be advised NOT to touch the boxes but instead to look for the visual and aural feedback from their SI Air Card (flashing and beeping).

tRicky we'll be following Victoria's lead in giving members the opportunity to download past Street-O course maps. There won't be controls though. Possibly MapRun will happen in a few weeks, and actual events some weeks after that.
May 2, 2020 2:55 PM # 
I am all for GPS punching in my training and think it can be a really useful way for new clubs with very few resources to get started.

Btw, Fossil, I need my phone for my work also. Initially I was concerned about damaging it. I put a case on it, put it in a map bag, and then in the main compartment of my Camelback vest. Been doing that for years and have never had any issues.

But I think for more serious events, flags and SI are important. I don't know any statistics on this, nor do I expect any research to be done on it. But I'm quite confident that if there's any high-risk area at an orienteering event, it would be the event center with the congregations of people there.

Everything else that happens in the forest seems significantly less risky than going to a supermarket based on what we know about how the virus transmits.

Unless we start a new habit of kissing each other in the woods. Let's not do that.
May 2, 2020 3:05 PM # 
Speaking of allergies, newest data, just published by Asthma and Allergy Foundation of America (AAFA):

2020 Allergy Capitals

1. Richmond VA
2. Scranton PA
3. Springfield MA
May 2, 2020 4:46 PM # 
Kissing someone while orienteering has been a rarity for me, but the last time I went to a normal orienteering meet, I did hug someone while in the woods. (I'll leave it to yurets to silently guess who.)
May 2, 2020 8:03 PM # 
JJ you son of a beech I heard you were after the best piece of ash in the forest. (from a Colin Kirk joke)
May 3, 2020 2:13 AM # 
Hmmm, I have come upon coupling couples multiple times whilst orienteering, but none of the involved parties were orienteers.
May 3, 2020 4:14 AM # 
Well this discussion took a turn I didn't expect...
May 3, 2020 5:32 AM # 
Its the AP equivalent of Godwin's Law. Any discussion will end up here if continued for long enough.
May 3, 2020 12:14 PM # 
To continue down the tangent this story again involves the late Colin Kirk. (The best ones do). He was closing up an event he was staging at Orford Provincial Park in Quebec. All the participants were back except one new couple who had gone out on the novice course. He set out to look for them and caught sight of them in a small clearing just off the trail. Yes, you guessed it: they were copulating.
Colin said he backed away and returned to the Finish, assured that they were more than all right. When they returned they told Colin they enjoyed the orienteering and definitely would be back.
May 3, 2020 12:51 PM # 
So he recorded them as a DNC... or not?
May 3, 2020 1:01 PM # 
I assume he was gentlemanly enough not to ask whether they had finished.
May 3, 2020 2:42 PM # 
We’ve been using MapRunF to set up GPS courses in London (5 so far). It’s a little faffy to set up and relies on your map to be geo referenced, or on you pre running the course with a GPS track (or both.)

Generally the tech works well, the only downsides are that:
1) you have to shlep your phone with you
2) GPS coverage can vary especially under foliage, so sometimes even if you’re in the right place the phone doesn’t punch, at least not initially

And of course, there are no flags so you do need to be 100% sure you’re in the right place - ok for easier areas / more competent orienteers, but not always.

So it works well for a ‘fun’ training course to compare times and maybe for a winter street orienteering series. But I can’t see it replacing ‘proper’ forest O.

The discussion on punching is interesting, as that probably is the highest area of risk. SI Air seems the way forward and has been reasonably well adopted here which is good. Definitely no need to ‘hit’ the station, most people will do a continuous ‘swish’ past the station to your ear to check the beep feedback.
May 3, 2020 4:27 PM # 
Why do people think that e-punching is so high risk? It sure seems like the main risk is prolonged talking/singing/shouting/crying/laughing in close proximity, rather than touching surfaces.

From the CDC website:

"It may be possible that a person can get COVID-19 by touching a surface or object, like a packaging container, that has the virus on it and then touching their own mouth, nose, or possibly their eyes, but this is not thought to be the main way the virus spreads."

Do they pose no risk? No. But the point of these restrictions on large events is to reduce the spread of the disease, not eliminate it.

Personally, I am happy to punch without touching the box or stand, and with hand washing before and after a run I would feel quite safe. If that's not enough for someone then maybe they shouldn't be at a public event at all.
May 3, 2020 6:42 PM # 
Thank you, Cristina. Exactly.
May 3, 2020 9:34 PM # 
Even in the United States the chances that the person you come across and coughs in your proximity has an active Covid -19 virus that chance is one in the thousands. Let's be careful but let's not develop phobias.
May 3, 2020 9:54 PM # 
One of the things that's been apparent in the last few weeks is that people are not very good at distinguishing between high risks (which seem to mostly involve crowded indoor spaces) and negligible-but-not-absolutely-zero risks.
May 3, 2020 11:04 PM # 
Also non-essential travel.
May 4, 2020 3:08 AM # 
I hope Boston Sprint will happen??? Any news on this? We are all deprived of orienteering....
May 4, 2020 3:44 AM # 
One of the points that Bob Turbyfill, former US team coach and head of coaching committee likes to make is: "Why do we hang a control flag in the forest?" Answer: "So people can find the punch."

Based on that argument, once we have reliable gps-based punching and no longer need punches, we will no longer need flags, either. Think about it.
May 4, 2020 4:46 AM # 
I like finding the flag.
May 4, 2020 4:59 AM # 
People did think about it. There is another reason to punch. That is to ensure fair and correct results when time is measured to 1 sec. There is no way GPS can satisfy this requirement. Can you use it for training and fun races, sure! Can you use it at races that matter to people, for sure not!
May 4, 2020 6:14 AM # 
Uncle JiM:
Defining what matters to people will be an interesting discussion
May 4, 2020 7:22 AM # 
I'm sure I have blinkers about some things in life. But tracking devices that are accurate to centimetres will come. Already orienteers with long arms get an advantage with contactless punching. View things through the perspective of the other vagaries that exist.
May 4, 2020 7:28 AM # 
Accurate to cm and reliable to give failure rate per control visited similar to what electronic punching systems offer today, it will not come anytime soon.
May 4, 2020 7:35 AM # 
Will it mean no more mispunches if it only beeps at a correctly visited control?
May 4, 2020 8:45 AM # 
Flag is not there just to find the punch. Looking ahead and around to spot the flag, sometimes simpifying by not reading details but following instead larger landform instead and just spotting the flag, running outside a nasty area trying to see flag from outside and then picking fastest micro route choice to flag (also when control feature is a bit large/diffuse you need to look around ad spot it). Flagless GPS punch method would mean replacing that with running about around there (sometimes that nasty area) and hoping to get a beep? As I see it some core part of O would be replaced with doemthing not equally neat. What it comes to beginners/kids it would repalce the joy and exitement of seeing and finding the flag. With joy and exitement of hearing a beep. Not sure is it the same thing.

Those are the main reasons I don't bother playing with GPS punch. Simply not worth it from my perspective, especially not for trainings. I am supposed to build race habits like spotting the flag, simplifying etc, why would I learn different/bad habits instead? I much rather focus on spotting the feature if there is no flags to spot. But I have features to spot, at featureless areas it may be slightly different, it may give more use the the area/map by providing more somewhat usable control locations.
May 4, 2020 9:45 AM # 
Of course we still have to hang flags. The interesting discussion is if GPS can replace electronic punching at "real" competitions with 1 sec timing. I think not, for the foreseeable future.
May 4, 2020 10:10 AM # 
Angelica - Boston Sprint Camp was cancelled. See
May 4, 2020 10:34 AM # 
For the competitive orienteer, it is indeed hard to see GPS replacing other timing devices any time soon. But for an entry to navigation sport, it clearly has a place today.
May 4, 2020 10:57 AM # 
Terje Mathisen:
Flags to quickly verify that you are in fact in the right spot, plus a honor system:

"Pass your hand within 30 cm /a foot of the flag without touching it, as if you were using touchfree EMIT/SI tags" would be sufficient for all races below national championship level, and possibly even those.

You could argue that a national/regional championship which could then lead to international championship starts would require more, just to remove the suspicion that some people would have from seeing the gps track fail to exactly hit all the controls.
May 4, 2020 11:50 AM # 
plus a honor system

No good, then those of us who don't win events cannot compare individual splits to see if we won any (in particular the all important finish split).
May 4, 2020 11:53 AM # 
Uncle JiM:
GPS has been guiding agriculture units (tractors, headers, sowing) for years with an accuracy of less than 30 cm
May 4, 2020 12:01 PM # 
Sailplane and hang gliding competitions work exactly like this hypothetical GPS-only punching, since you can't hang flags in the sky. But they also use the GPS to guide you to the destination, rather than forcing you to read a map. The controls are defined as a radius around a point, which varies, but which is very large by our standards. And the navigation software isn't trying to get to to the center of the circle, but to the closest point on the perimeter. It's... weird.

GPS-only punching would change the focus from finding a specific spot to instead the overall route. It would change things substantially, though it might be adequate and appropriate for Rogaine.
May 4, 2020 12:04 PM # 
Agriculture units generally operate in areas with a better view of the sky than orienteering, and they aren't constrained to a tiny unit you can carry on your wrist.
May 4, 2020 12:05 PM # 
Uncle JiM:
Correct. But years ago I use to carry a brick type mobile phone around, I don't any longer
May 4, 2020 12:08 PM # 
Wearable consumer GPS watches have if anything evolved towards worse accuracy the last several years. Size and style is much more important to the average user than positional accuracy.
May 4, 2020 12:13 PM # 
The problem with honor system is competitor visiting wrong control without noticing it. I do it every now and then (and get disqualified). honor system + recording gps track would be better, track to be used just for post race analysis and comparisons (like split times between any two points, not just contols). And for competitor noticing and self-disqualifying for taking wrong control without initially noticing it.
May 4, 2020 12:14 PM # 
I just want a GPS with a band that doesn't break so often.
May 4, 2020 12:15 PM # 

May 4, 2020 12:45 PM # 
The problem seems to be continuous GPS accruacy at running speed and under heavy tree cover.

I’ve been re running my own MapRun course a few times and often one of the controls doesn’t register as the GPS is not accurate enough at that point in the run.

The other thing about using GPS is that map quality has to be 100% all the time. With flags, you can get away with minor inaccuracies without being unfair.
May 4, 2020 12:58 PM # 
Consideration of GPS punching is often rolled into the separate issue of marking the site with a flag. And the red herring of device sizes and accuracy at the present.
May 4, 2020 10:31 PM # 
Forget about Covid, infamous Japanese Giant Hornet arrived to America
May 4, 2020 11:34 PM # 
Washington state has to worry about the hornets. The rest of us can keep worrying about the virus.

My sympathies are with you, WA state dwellers. :-(
May 5, 2020 12:31 AM # 
They'll spread. Cane toads started in Qld, Aus, but they migrated across the whole country. Much like all the other introduced species we have here.
May 5, 2020 12:33 AM # 
Europeans, for example?
May 5, 2020 12:35 AM # 
I didn't want to say it but it's out there now.
May 5, 2020 12:46 AM # 
We have that over here as well.
May 5, 2020 3:23 AM # 
The centimetre accurate GPS in agriculture is corrected by a correction signal from a base station or satellite. If its a base station, then flat cropping country has an advantage. If its satellite, then you have problems with canopy that croppers do not have, particularly if its a geostationary orbit and you are in higher latitudes, which orienteering often is. I was using a real time corrected device for mapping some years ago, operating off a geostationary orbit satellite. It didn't take much canopy to lose signal. And I was using a backpack antenna that I can't see being popular in competition.
May 5, 2020 6:29 AM # 
Terje Mathisen:
Even if you just have flags, you still need a control identifier, i.e. an alphanumeric code which you can verify on your clue sheet.

Re. self-DSQs: They are no laughing matter, here in Norway Olav Lundanes have DSQ'ed himself even on quite important races like the Sprint-O national championship in Arendal (of "Frozen" fame!) which he won before realizing that he had cut behind a garage which did in fact have a tiny splash of olive green in it (in reality it was just a meter-plus wide concrete alley).

I wasn't the MC leader at that time, but it was clear after the fact that the map was in fact broken, i.e that patch was below minimum size so nobody else thought he deserved that DSQ.

Here you can see if you can spot the issue:
May 5, 2020 7:46 AM # 
The other thing about using GPS is that map quality has to be 100% all the time. With flags, you can get away with minor inaccuracies without being unfair.

Only if you pick control coordinates from map. If you pick accurate coordinates when placing flags then map inaccuarcy (error in absolute position) doesn't matter. I mean here gps puching with flags in forest.

GPS punching has problems with conrols under concrete canopy, rock holes, indoor orientering. Also moving control some meters last minute is problematic (for parked car, angry restaurant owner etc) so controls may have to have gps too. And if there is electronc devices at both sides then it is questionable is GPS really to best technolgy out there to measure accurate distance between two devices. By the time GPS with cm accuracy under canopies and concrete is here, there most likely is other technologies too and most likely some of those are simpler, cheaper and more reliable. Those who say GPS punching will take over when accuracy is here seem to think GPS is the only technology still proceeding.
May 5, 2020 10:31 AM # 
Terje Mathisen:
@Arnold: 100% map quality? No, you just need for all maps to be properly georeferenced! Starting with a LiDAR base map you will never introduce adjustments and exaggerations large enough to matter for GPS-based tracking, and like Jagge said, you just need to make sure you place the (virtual) flags in the correct spot.

The most difficult issue might be controls in reentrants, they are typically drawn with the center slightly above a specific contour bend, sort of in the center of gravity of the part of the contour that fits inside the circle, but quite often placed 5-10 m above or below that specific point in the terrain.
May 5, 2020 12:01 PM # 
Even if you just have flags, you still need a control identifier, i.e. an alphanumeric code which you can verify on your clue sheet.

Actually, maybe you don't. I'm assuming that, like UsynligO (or an airsports variometer), the unit gives you an indication (probably audio) when you get to the right location (or close enough). So you wouldn't be looking for a feature, you'd just be trying to "the circle". There might not even be a feature in the circle, though at that point course setting needs to be very careful. I'm not a fan or this idea for regular orienteering, and it of course wouldn't work for Sprint orienteering with traps as described above, but we've been thinking about it for some areas in the western part of the USA where for various reasons putting out control markers would be difficult, for Rogaine-style events.
May 5, 2020 12:17 PM # 
alphanumeric code doesn't stop people from taking wrong controls without noticing it. Last time (Kainuu O week 2017) I learned 248 ≠ 284
May 5, 2020 12:24 PM # 
Terje Mathisen:
@Jagge: I know, but it doesn't make it any harder than today. :-)
May 5, 2020 2:31 PM # 
@Terje, even with Lidar there can be a little bit of interpretation by the mapper as to what exactly is mapped or not (as proven by the ‘get 10 map makers to map the same bit of area and get 10 quite different results’ challenge!)

If a flag is 5m off the ‘perfect’ position in the terrain you might not notice. In GPS you probably would.

And also, even as an experienced orienteer I find it a little stressful to run a course without any flags at all. Am I really always 100% sure to be in the right place? The flag gives me confidence that I am, with GPS you won’t know until the finish, unless you hear the beep at every control - which can be tricky.
May 5, 2020 4:10 PM # 
GPS will give an indication when you have reached the correct control, and will presumably also tell you which control you're headed to next. And it's going to have a substantial radius for deciding that you're in the right place. The current recommendation seems to be 25-35 meters.
May 5, 2020 8:42 PM # 
We’re using 15 metres, but that may indeed not be sufficient.
May 5, 2020 9:32 PM # 
When I'm moving faster 25-35m seems to work best with the apps I've tested so far: GPS orienteering, Usynlig, MapRunF.

I've only done a short test with O-range. But its max is 20m.

GPS punching is really useful for individual and club trainings. And the club out of Asheville, North Carolina got started with Karttapullautin and GPS orienteering. So it can definitely serve some purposes.

But in the long term, I don't think GPS punching should replace Sportident and Emit.
May 5, 2020 9:42 PM # 
I've found that ORange at the default 15m is working pretty well, but sometimes the GPS signal will lag by 4-5 seconds. So I get to the center of the circle, but the range still says 20-30m, but if I slow down momentarily, it settles within the 15m and beeps.
May 6, 2020 7:14 AM # 
I find that too. rather than lagging, could it be that the calculated position is constantly flitting to and fro (ie look at what a 1sec track does when you are stationery). So when you arrive at the control (assuming that's perfectly positioned) the spike may just happen to be unfavourable. But it will soon flit past the correct point, maybe even out the other side. Those who know more may be able to dash this theory:-))
May 6, 2020 7:29 AM # 
Terje Mathisen:
The GPS chip itself just delivers 7 parameters every second, i.e. the results from the time/pseudorange/doppler measurements, these are (x,y,z,dx,dy,dz and time). On top of that you always have some form of filtering where you combine multiple measurements in order to smooth'en out the track. This can be a Kalman filter or just some form of low-pass/averaging. All the processing take significant time, so there might also be a prediction component, i.e. "this is where we believe you are just now".

An orienteer running under wet canopy, stopping and starting, changing speed and direction all the time is pretty much a worst case scenario for those algorithms, but if they were willing to use more power to run the multi-constellation gps chip at full capability, and also connect it to a good antenna, then we could have had meter-level tracking most of the time, but not in a small watch form factor.
May 6, 2020 8:35 AM # 
The other thing I was wondering, does it matter which phone you use for your GPS? I run with an iPhone 6s, which is pretty out of date technology now. So does that make the GPS track less accurate than if I were using an iPhone 11 for example?
May 6, 2020 9:11 AM # 
Don't cell phone 'gps' get their location in relation to the nearest cell phone tower, not the gps satellite network?
We use Livelox in Florida and get pretty good tracks from most of the cell phone users but every once in a while there comes a track that is wildly inaccurate.
More common is that 15 people running along the same trail can show 15 slightly different locations for that trail, for example.
I was told that was because the cell phone tracking just is not as accurate as standard gps units, even gps watches.
May 6, 2020 10:53 AM # 
Terje Mathisen:
The gps chipset in modern phones are the best ones available, bar none: The difference comes from the way phone manufacturers use that extended precision/multi-constellation tracking to get way with using less power, i.e. don't actively track all sats at all times, don't use multiple channels to track both the main path and one or more reflections inside an urban canyon etc.

They also use cell network augmentation to download fresh ephemeris for all sats as well as approximate location and pretty accurate time: Armed with that data the gps unit can lock onto most sats in a couple of seconds.
May 6, 2020 11:44 AM # 
@Terje- is it #5 the control on that Arendal map? if so, good thing that i could zoom out the image
May 6, 2020 11:59 AM # 
Uncle JiM:
I thought #5 as well, and if so, he gained no advantage going through
May 6, 2020 2:39 PM # 
Terje Mathisen:
Yes, it was #5, and Yes, it was effectively impossible to read this sub-size patch at competition speed, but when Olav had already DSQ'ed himself, nobody dared to reinstate him. :-(

I ran through the course a bit later and as I said, the narrow alley between the garage and the wall had no visible reason to be mapped OOB, it was just plain concrete.

This is in fact the main problem with hosting a sprint championship: You can invest near-infinite effort and still the best you can hope for is that nothing goes critically bad.
May 7, 2020 12:03 AM # 
Oh the penalties of being famous! When I do something like that I "own up" - and hope that the organiser says "thanks, you didn't get an advantage, don't worry about it". Sometimes they do sometimes they don't.
May 7, 2020 3:24 AM # 
phones use gps the same as any other gps unit - the position does not come from cell tower triangulation. As terje says newer cell phones have very good chips capable of very high accuracy but the algorithms they use might sacrifice accuracy for better battery performance. Most users don't care about accuracy as much as orienteers would: +/- a few m is fine for most users.

Those occasional wildly inaccurate tracks are probably due to reflected signals
May 7, 2020 5:44 AM # 
Terje Mathisen:
What most of you have probably noticed is that when a GPS track goes bad, i.e. develops a 15-30 m offset from the path you know you followed, it tends to stay that way for a while, right?

This can be either due to a reflection, i.e. when there is a steep face on one side of said path, many/most runners will see their track reflected sideways away from the steep side, or it could be due to a temporarily bad sat geometry. The latter is usually not a problem for modern chipsets, but when you are tracking a secondary (reflected) beam, the gps will stay locked onto that beam for a while even after the primary/direct beam returns.

However, the primary reason for sustained errors is probably due to the gps filtering, i.e. when the position is bad at time (a), and you then move a given (dx,dy) distance (as given by the gps doppler signals) that lead to a new position which is relatively correct but wrong by the same absolute amount.
May 7, 2020 6:51 AM # 
I've noticed this phenomenon (of good shape but wrong position) when mapping - but with smaller "errors" say 5-10m . I can sometimes be sure what the right answer is where I can see something on the imagery, and this gives me a reason for moving the whole track sideways before using it as the basis for drawing my (e.g.) path. I don't have to know WHY the error is occurring, just that it seems to be consistent.

It would seem that any waypoints I record in such a zone should be moved by exactly the same amount before using as the basis for a point feature, but I often feel (from other information) that they do not share the same error. I wonder if the same algorithms are being applied to waypoints as to tracks? I don't do waypoint averaging.
May 7, 2020 6:58 AM # 
At the China WC trip last year, olive green in lanes (similar to the #5 case in Norway) was used for alleyways which were too narrow (generally < 0.6m) to be safely passable - some would say that some of the ones which were shown as passable were fairly borderline - but we taped anything where the status might be in doubt to a runner.
May 7, 2020 8:45 AM # 
Terje Mathisen:
I found the Arendal olive green trap on StreetView:,8.7627471,...

It was a concrete power transformer housing, not a garage, but the alley is clearly visible, with what looks like a two-step staircase leading into it. I'm guessing it is approximately 80-90 cm wide?
May 7, 2020 9:50 AM # 
I used to get good shape but consistent 2-8m wrong position with gps watch. error was almost all the time to the watch hand side. Then I figured it must be combination of my body shadowing the other side and watch antenna being aimed to the other side making reflections from ground/nearby trees much stronger than those direct signals though my body at dead angle of the gps antenna. And chip simply thinks satellites at that side are some meter further away than they really are. So I began to keep my watch different way (aim antenna straight up or even slightly at me) and that error magically dissappeared.
May 7, 2020 10:57 AM # 
Wow! But that's not the source of my errors. I wear an external antenna on my head when I'm mapping. I guess the errors have many sources, and different ones will dominate in different places and times. Like I come back tomorrow and get a difference - that's probably position of satellites and which ones are being used?
May 7, 2020 11:17 AM # 
you know that if you are using aerial photos (orthos) you have be careful about tall objects. Even if the photos are well georeferenced, unless a tall object is in the dead centre of the photo there will be a error in the apparent position of the top of the object This becomes obvious if you have veg info from lidar and compare that with an orthophoto. The lidar will be accurate.

Also I find that often orthophotos are not accurately georeferenced and it is not uncommon to have errors up to 10m or more if you compare with lidar. These errors are not consistent across the photo - some places it is accurate others not.

[if someone tells how I'll try to make the picture in the link above appear in this post - and after some research I figured it out myself]
May 7, 2020 11:52 AM # 
unless a tall object is in the dead centre of the photo there will be a error in the apparent position of the top of the object

Welcome to campus sprint mapping!
May 7, 2020 12:25 PM # 
but most campuses I have mapped are in urban centres that tend to have lidar coverage - I just use the lidar generated vegetation maps. Only use orthos for ground level stuff I can't get from the lidar - paths etc.
May 7, 2020 12:44 PM # 
robplow's picture (courtesy of the HTML img tag):
May 7, 2020 1:02 PM # 
thanks JJ - can you tell me the code to do that.
May 7, 2020 1:15 PM # 
May 7, 2020 1:32 PM # 
I used to call this 'parallax' but then I googled it and got this definition:

The term “parallax” refers to the apparent movement of objects when viewed from different positions. The everyday example of this is seen driving on the highway-- when you look out the window, electrical poles near the road seem to zoom past, while trees in the distance appear to slowly drift by

So I don't think parallax is actually the correct term for this - but I don't know what is.
May 7, 2020 1:40 PM # 
with buildings in orthos you can compensate by identifying the corner or side of the building you can see meeting the ground - so draw the outline of the top of the building and move until the corner matches the one you can see meeting the ground - still not perfect but a lot better. Doesn't tend to work with trees so well unless you can see the trunk through the foliage - leaf off photos are great for that . Unfortunately Australian trees don't lose their leaves, except in bushfires.
May 7, 2020 2:32 PM # 
The correct term is relief displacement.

Unless I'm missing something, wouldn't it also apply to tall buildings and similar objects in the across track direction of a lidar scan? Or do the lidar processing algorithms magically correct for it? (I've never paid much attention to the technicalities of lidar scanning)
May 7, 2020 3:00 PM # 
A plane flying lidar pumps out laser pulses as it goes. And presumablely the plane flies in a grid pattern such that the footprints of the pulses have significant overlap. So any object on the ground will be bombarded by pulses from many different source points. (A photo has a single source). I have no idea how the processing of all those points works but I am told the algorithms take into account and correct any relief displacement effects.

In any case I know from field experience that lidar vegetation plots match the contours well, whereas the apparent position of tall objects on orthos often doesn't.
May 7, 2020 3:05 PM # 
I don't know the technical details of it but the result of the lidar is a set of x,y,z coordinates for various points with further detail (intensity at least), added to each point.

This is the point cloud. Therefore as long as the xyz for the point at the top of the building is accurate it doesn't matter if it was caught at an angle or not.
May 7, 2020 6:58 PM # 
Terje Mathisen:
I do know the technical details, but I won't bore you with a 2-3 hour explanation. :-)

The q&d version is that the plane/helicopter flies over while the LiDAR scanner sends out maybe 300 K pulses per second, using one or multiple frequency beams. While doing that the plane also collects either full gps pseudorange data (for post-processing the scanner position) or real-time kinematic positions. Both are typically accurate to 2cm in 3D, so including the spreading of the laser beam and any remaining jitter in the scanner position and directional angle, you end up with pulse returns which are accurate to the 10 (5-20) cm level. Each pulse will typically generate multiple returns if there is any kind of vegetation, up to 5-7 (x,y,z) points can be identified for each pulse.

From this huge point cloud you must first determine which returns are from the ground, this is typically only the last return from each pulse which will be considered here, but it is still almost black magic to create a good selection of ground surface samples.

The next steps are to locate buildings (most easily by locating locally plane surfaces, i.e. roof sections), and then what remains above the ground surface will be assumed to come from vegetation. The density and height distribution of these vegetation points relative to ground points can be used as a proxy for ocad vegetation classes.
May 7, 2020 8:53 PM # 
So when exactly are we starting orienteering again? :-)
May 7, 2020 9:42 PM # 
Depends which country/state you're in... Some have already/are about to recommence.
May 7, 2020 11:58 PM # 
but I won't bore you with a 2-3 hour explanation

Go on - not like we have anything better to do right now
May 8, 2020 2:15 AM # 
It is a parallax error if you assume the location of the top of the building has been determined from directly overhead when it has been determined from an angle to the side.
May 8, 2020 2:32 AM # 
I thought Parallax was that dude that was trying to destroy the Green Lanterns.
May 8, 2020 5:10 AM # 
Lidar has it's own oddities. Like high returns (from birds - and ufos for sure) and low returns well below ground. Like beam hitting wells or manholes. I have heard some suspect cars with chrome bumpers or something, beam reflecting from mirror-like surface and reflect back from some object further away making return look like it's coming far underground. Now some ground classification algorithms pick lowest points as initial ground points and start classifying there and when it starts mostly from such points under ground there result can be funny, none of the actual ground points above may not end up as ground.
May 8, 2020 8:01 AM # 
Terje Mathisen:
Jagge is right, as usual! :-)

Ground surface determination is as I wrote partly black magic. All the serious algorithms starts by trying to discard noise/outliers, which of course includes points where the laser beam has been reflected multiple times and therefore appears to have come from well underground. You typically start with a fairly coarse set of triangles, based on last returns which are locally not too far above or below their neighbor candidates, then you refine this by looking for more last returns which are reasonably close to this initial surface, then you rinse & repeat.

An unstated but very crucial assumption here is that the land surface behaves "normally", i.e. in the previous generation of Norwegian LiDAR the ground points in steep hillsides would consistently cut off terrasses above little cliffs, instead pretending those points were all vegetation. I used to have a separate processing step in my pipeline specifically looking for this situation, and it found a lot of real cliffs. With the latest effort which is about to cover the entire country, the baseline data is so much better that I have commented out that extra stage.

@robplow: There are two main types of laser scanners, one that uses a vibrating mirror to bounce the beam back & forth sideways, meaning that the beam speed and pulse density changes across the beam width, the other approach have multiple mirrors on a rotating axis so that the beam scans more like an old TV, always going in one direction before jumping back. This is more stable but makes it impossible to control the width of the beam except by flying higher or lower.

As I mentioned you can also have multiple laser beams (of different colors) going at once, this will both increase the pulse density and return much more information about the surfaces/objects that are hit. I.e. similar to the difference between b&w and color photos.

The really amazing thing is how it all works! :-)
May 8, 2020 9:45 AM # 
If it is an art form, there are some very good artists out there. With all the potential for error, I rarely come across much to reduce my confidence in the technology. My first map with the technology was in 2011. Across five square kilometres of mixed mining and gully-spur terrain I came across only two missed pits. Both could be explained by angled trees close to the pit. After that experience I started trusting the lidar to tell me to put my effort rather than using effort to check the lidar. Of course, mounds are a different matter. Varying ground reclassification parameters doesn't fully improve the detection. Thankfully, in the local terrain the only reason there is a mound is because someone has dug a pit. The lidar will find that.
May 8, 2020 10:29 AM # 
Terje Mathisen:
@TheInvisibleLog: As I wrote, the newer data here in Norway is so good that I've stopped worrying about it, although there are still obvious errors.

You mentioned mounds, the same goes for boulders and small dense shrubs: They have pretty much exactly the same Lidar footprint but could be mapped with brown, black or green. :-)

I have had some success in Colorado recognizing boulder fields as green stripe vegetation due to the nice mix of ground and near-ground returns. Individual boulders are pretty much always skipped unless they are house-sized.
May 21, 2020 3:27 PM # 

These are 10 years old tracks from the time before Glonass. 3k track run, skate skiing, and trail runniing. One of these tracks were recorded with gps watch in hand, rest are gps inside my cap (technologies in par or same device). Can you spot which is the watch style one? (And note the one with tiny zigzag, that's uphill skate skiing). Body shadow and antenna rotation sometimes makes big difference.

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