KA72 required for GPSTC

Surely not Shear Tip. Prominent leaders of the committee are on public record saying they refuse to use KA72 as they prefer their independent software. So I find it hard to believe they would question a track because a session was uploaded using something different than KA72....surely there wouldn't be double standards at play....

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TRIMMER said..

shear tip said..
Hey, GPSTC admins, I'm curious - is it now a requirement to upload through KA72? Are tracks being queried if they're not uploaded through KA72 and are from a GT31?

From what I have seen your tracks only get queried if you post through ka72 and not by any official, just a couple of bored retired WINGERS with nothing else to do.

I have been queried, before the existence of KA72, so your analysis is false.

Are you just being nasty for being-nasty-sake ?

The analysis is very much NOT false Matthew. Let's just wait to see what the committee members have to say as they are the ones we are calling out here. Unless of course YOU are one of the ones involved. In which case you and the rest of the committee have some explaining or back pedaling to do

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decrepit said..
Definitely GPSTC has no requirement to post via KA72.
In fact I'd rather you didn't, but that's just my preference.
I think GPSspeedreader has better filters, but Dylan disagrees.

And yet that's not what was said in a particular email is it Decrep

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sick_em_rex said..
The analysis is very much NOT false Matthew. Let's just wait to see what the committee members have to say as they are the ones we are calling out here. Unless of course YOU are one of the ones involved. In which case you and the rest of the committee have some explaining or back pedaling to do

Since it was said here with an all-encompassing-statement, there only needs to be a single instance of it not being true, for the statement to fall apart... this is how science works, it is how laws work, and politics.

I'm not part of the GPSTC committee AND I have supplied my track not via KA72 - QED.



The nastiness from some people on this forum, towards the stewards of the GPSTC, has to stop. If the same people were to meet on the beach, there would be no arguing and bitching about anything... because the sailing comes first. But it seems people think that being an internet-troll while posting on a forum makes it ok to be nasty to people. It really isn't. So just quit it.

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AUS3333 said..

mathew said..

If the bait ain't set for you don't bite

Again... that is just-being-nasty-for-nasty-sake.

What is wrong with you that you need to be nasty to someone ?

Interesting to see, said file has now been removed, rather than submit it for evaluation.

Mathew,
the original post was a question posed to the GPSTC administrators. Since you have stated that you are not in fact one of them I respectfully ask that you keep your passive aggressive and quite frankly patronising comments to yourself and keep out of something that does not concern you. Your diatribes are just boring.

Decrep, thankyou for your replies. I think considering your public exposure of said email it highlights for all to see the ambiguous nature of the request. It is very easy to interpret that email 2 very distinct ways. The language, tone and poor grammar are what concern me and others I have discussed this with the most, hence why we thought we needed to call the Committee out on this. As leaders of the GPSTC you are expected to show leadership and professionalism, something that is sadly lacking in this instance in our opinions.

Might I suggest for the future a much less ambiguous and controversial request such as the below;

Hi (insert GPSTC user name here),
congrats on your session posted on (insert date in question here). From time to time the Posting review team from the GPSTC committee like to validate sessions showing pb's. As your session contains pb's we are requesting you kindly send us your file from this session so we can run it through our software just to check its validity and to make sure there are aren't any spikes or errors. A lot of users post using KA72 which has an uploaded file we can access without having to request this directly from you but on this instance it looks like you have posted using another independent software and so hence our request to you.
Once again congrats on a great session and we look forward to hearing from you so we can confirm the validity of the tracks.

This is just a suggestion. We have tried to make it friendly and non confrontational. Use it, don't use it, it makes no difference to me. I am just trying to help the admins clear up an area of obvious angst.

I dream of getting one of those "please explain" emails. It means I might have scored a pb!
I do not find GPSTC email wording confronting but Sick em Rex's wording is less open to incorrect interpretatlons
A good improvement.

Thanks Rex, your suggestion is less confronting, the people that write these requests may or may not take notice.
Requests for files, aren't just about PBs.
Checking PBs is really the captains job.
Anybody can flag a file to admin, for a number of reasons, (hopefully personal vendettas aren't high among them). If the concerns look reasonable to admin then the file will be looked at.

Anybody can make a mistake, gps left on during drive home, best 10s being posted for 5X10, 500m being posted for @500, etc.
KA72 will let stuff through that is unacceptable on the database, we've just had an out of adjustment canmore post with 5s intervals, for instance.
So some things just look wrong and need to be checked.
Quite often the file is legit, like one good gust giving a high NM and 2s but low 5X10, this makes the NM look a bit suspect, and needs checking.

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shear tip said..
The original question was just asking for clarification of the rules. Now the email has been posted, you have to admit, it could be read one of two ways:

They note that it was not not posted through KA72 so we need to get it from you.

They note that it was not not posted through KA72 so we need to get it from you.

With a bit of imagination I guess.
Probably best to leave the reference to KA72 out altogether?

Remember folks, this is just for fun and as I'm on the advisory committee I don't do it for the gold and girls.
I also don't get paid for my spelling, grammar or playing nice with others

I normally post via Ka-72. Just for the fact anyone can view/download it. And always only post on GPSTC from the one device! So that can be clearly seen. I can see both sides and sometimes I've posted my session ran through another program. It's definitely great to have the option to check a file through several programs to validate. I can certainly vouch for Daffy being a great help. On a recent file of mine. But to many many others also!
Ps isn't there any wind around the country!?!

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mikey100 said..
On another note. My friend beat me by .010kts over '2sec' the other day- this equates to 1cm (yes 10mm) over the "max 2 sec" so, I was wondering if anyone could help me work out how I could bridge that gap. I don't like him beating me by so much.

Cut the band off your watch Mikey and have in pouch connected to your vest.... you will beat me for sure

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mikey100 said..
Having just spent time sailing with a large group of speed-sailors from around the country, I was bemused at the end of each day to see some running their tracks from their 3 or 4 worn gps devices through multiple programs in order to get the best result in the speed category that they were targeting. I was also amazed to see the wide variety of results that could be obtained from the same session. It appears that I may be letting myself down by using just 'one device and KA72'!
I also learned that there are 'fast' and 'slow' GPS devices, so I am still hoping to be able to buy one of the 'fast' ones if I see one come up for sale. Now, although not having any idea about coding or programming etc, I offer a possible opinion/solution to help alleviate some of the issues that have been voiced in this, and many other forums...
If GPSTC had its own specific, analysis program (similar to KA72) which ALL tracks had to be submitted through, then everyone's data would be run through the same program/filters. It could then directly fill in the data on the sailor's page. Also, all tracks could then be easily available for GPSTC committee review. This would solve many issues, wouldn't it? But again I admit... I have no idea about the logistics of this idea... so I patiently await the bullets!
On another note. My friend beat me by .010kts over '2sec' the other day- this equates to 1cm (yes 10mm) over the "max 2 sec" so, I was wondering if anyone could help me work out how I could bridge that gap. I don't like him beating me by so much.

Thanks Mikey, you bring up some good points that have been covered before in these forums, but are well worth reiterating and expanding on. This is probably not the ideal thread for it, but this is where you brough it up.

Wearing 2 or more GPS devices is sensible and encouraged. It is specifically mentioned in the rules: gpsteamchallenge.com.au/pages/rules

"Using multiple GPS'sGPS devices sometimes can fail, or users can sometimes make errors in use that can result in lost data, or no recorded data on a device, so users are encouraged to use multiple GPS's if they wish to have backup redundancy. In such cases, users should select the complete set of data from only one of the devices to post from the device with the lowest +/- numbers, unless the technical panel gives an individual case approval."

There are a number of reasons including: One or more of them might loose satellite, lock or signal, and not have a complete record. (this happens - ask the guys from Budgie/Lake Mac/Wello etc)

Sometime GPS's dont work as we expect them to. Sometimes a GPS will just die or run flat. 90% of the time is is a user setting or wearing error, but it happens. It good to have a back up

In a very few cases, some sailors are trying for a GPS record where an average of 2 GPS's are required.

All approved gps's have been tested endlessly in side by side situations. We have proved that they will all give the same result within the reported error margin 99% + of the time. Therefore, for results within the error margin, every GPS can be said to be no more or less accurate than any other it is worn with. That said, it is also stated in the rules that the GPS with the lowest error should be posted from and all results should be posted from one GPS only. If in doubt, consult your team captain and/or the GPSTC.

'Fast' and 'Slow' Devices: I have heard some sailors say that one of their devices always gives a higher result. This is not as simple as it may look at a casual glance. One must also look at the way the gps was worn, the error margins reported, the number of satellites used, and have a look at quite a large sample. In all the hundreds of side by side testing sessions I have done with multiple GPS's, I have yet to see any GPS that consistently give a higher result when these factors are taken into account. If you think you have one, perhaps it is faulty and need to be properly tested and eliminated from use if it is faulty.

One other factor in this is the Hz rate (1Hz or 5Hz). A higher Hz rate (readings per second) will almost always find a slightly better result over the short time spans of 2 seconds and especially 10 seconds if the run is a typical accelleration curve from low to high speed and back down again. This is because it can find the optimum speed 2 or 10 second segment with finer resolution. It is still completely 'real'. But the difference is usually measured in 0.1 of a knot or less. It is, in this case, sometimes an advantage to use a 5Hz or 10Hz device, and the difference is both real, and quite small.

For the Alpha category, we have a situation where the technology is still not good enough to be up to 'world record' type standards as we must rely on the positional data (trackpoint) for calculating the 50m proximity circle (Doppler is used for the speed). Since we can't rely on much better than 3-6m accuracy for that parameter, results between GPS's may vary more if the return path is right at the 50m limits (as it is on many of the fastest Alphas). All we can do is accept it for what it is and give the sailors the benefit of the doubt. If we ever get cm accurate locational data (e.g. RTK), this may improve considerably.

Software analysis programs: All the approved programs are well tested and their authors have cooperated on the specifications of the various categories so they all give pretty much identical results. Any differences you find are usually due to different filters or the way the program handles errors or missed data points. RealSpeed may sometimes produce weird results with the new 5 and 10Hz devices, as it has not been updated for quite some time to account for some new developments. If you like using this program, check with me that you have the best version for the devices you use it with, and check your results against other programs if in doubt.

In the 1 hr category, some programs handle missing points and stops, or low speeds differently, but for most one HR results, especially higher speed results, there is no significant difference.

In the Distance calculation some of the same factors apply. Even without making the effort to set up the program to the same base parameters, the results for distance are usually within a small, and usually insignificant margin. If they are not, then something may be wrong with you program settings or your session file, and you should seek a second opinion from your team captain or the GPSTC.

Different programs are often used to find or resolve apparent errors, or for other validation situations. They are extremely useful for testing and research and they can sometimes highlight things in different ways or provide data in a more useful way. Some programs are a lot easier for doing certain things, like cutting off your drive home, a common issue (RealSpeed/GPS-Speedreader) or combining split files. or averaging results from two GPS (GPS-Results). GPSAR-Pro and RealSpeed have the facility to produce a complete tabulation of the entire session including columns for all the different types of data that a GPS device outputs. GPSAR can also run multiple tracks in 'replay' mode for you can visually compare yourself with others on the water near you. The newest sftware program, GPS-SpeedReader, can produce an excellent Google Earth trackmap Graphic. There are many more examples.

But the bottom line is that they will all produce identical, or almost identical results if set up correctly and running a fault free file. If you find a difference that makes a material difference in your results, you have probably found a data problem and need to seek expert assistance.

The KA-72 website program is an excellent service and has clearly made GPS session analysis and posting very much more accesable and easier for a large number of sailors. It is designed for this purpose and also to work with almost any GPS device file. It does an extremely good job if this, and this is why so many sailors use it and love it. I think Dylan would be the first to agree that this also nessasarily enforces limits in some other ways that dedicated analysis progams do not have.

To summerise, there is no one single analysis program that is perfect, or can be all things to all people. This is why the rules of the GPSTC are written as they are. We trust that the upcoming changes to the GPSTC website will help us to alleviate almost all the posting and session validation issues in a much simpler way, without tying the GPSTC to one 'unicorn' session analysis program. In the updated system, all session files will either have to be public on KA-72 or uploaded to a GPSTC database where they can easily be checked if nessasary. No more need for the GPSTC to ask for files and the often misinterpreted implications associated with that.

Oh, and Mikey, to brige that 0.1Kt gap, you just need to sail a tiny bit faster mate!