How long must we endure this nonsense from KA72 being posted to GPSTC?

Here is a post from Saturday from a Lake Macquarie team member using a Mini Motion and posting through KA72.
www.ka72.com/Track/t/509426
Reported 2 sec peak from KA72 of 18.437 when clearly this is a spike from a fall.
The correct result can easily be seen in other analysis software as 13.686 . Fortunately, this member was wise enough to realize the issue and posted from a different device.
However what is the point of all this fuss about recording accuracy data if KA72 (the most used posting service) does not correctly process this information? This has been a well known issue for some time.
How many times is this happening and not being picked up?

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powersloshin said..
And I give you an example from my files, where the max speed track is impossible, but the error was not picked up by GPS Results or GPSSpeed reader either, so I just posted the second best speed, which was legit: www.ka72.com/Track/t/503671

That's odd, I just checked this file in GPSSpeadreder, and it filters out that obvious bad result.
Have you disabled the filters in yours?

It's so bad accuracy is from +/- 2 to 3kts any software should discard this part of the track.

This is a hard one, being able to download peoples tracks is good, but also posting rubbish is bad.

I'd prefer people to post to the GTC from GPSSpeedreader (with filters set to default) and just post tracks to KA72.

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powersloshin said..
The main reason to post to KA72 is that all files are available for download and scrutiny by all members, if kept public. So any post can be easily checked with other software if wanted.

And I give you an example from my files, where the max speed track is impossible, but the error was not picked up by GPS Results or GPSSpeed reader either, so I just posted the second best speed, which was legit:

www.ka72.com/Track/t/503671

I also downloaded the file you mention and same issue: both SpeedReader and GPS Result validate the crash data.

Only if you disable the filters in GPS Speedreader, or change their values. Note that when you do this, the "Post to GPSTC" button on the result web page is disabled, so you cannot post this directly from Speedreader.
Here is the region in Speedreader with default filters enabled:


The entire crash region is filtered (red) because the error estimate is above the threshold (1.2 knots for Motion data).

This region is obviously NOT filtered by ka72.com. The likely reason is that ka72.com uses a different threshold - most likely either 2 or 4 m/s. The important part is the unit: it should be knots (as in GPSResults and in GPS Speedreader), but instead is m/s, so it's actually about 3.9 knots (or even 7.8 knots), which is way too high.

The unit bug for the speed accuracy filters actually means that the error estimates in GT-31 data are totally ignored by ka72.com, since the threshold (7.8 knots) is higher than the maximum value in GT-31 data(just below 5 knots). For Motion data, they are just much too high. All this has been pointed out many months ago, but nothing changed on ka72. Quite ironic, considering that only units with error estimates can be approved for GPSTC, but for postings made from ka72, error estimate filters do not work (and probably never have worked).

Thanks for the explanation, I never played with the filter settings, had another look:
The points are marked red, but the best speed in bold is still the wrong one.
This is just to understand better how the software works, I love your program and highly value what you have done

Same for GPS Result, filters are set to default

Thanks Andrew !

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powersloshin said..

powersloshin said..
Thanks Andrew !

Updated to latest version and now the invalid speeds are filtered out. I will keep using ka72 , but also check in GPSSpeed reader - was already doing it before

May I suggest, posting to GPSTC from speedreader, it's just as easy as from KA72, just view in browser, and hit the upload to GPSTC button, just upload to KA72 for everybody else's benifit?

Ka72 also has the disadvantage of using a different Hr algorithm. You could conceivably loose a PB hour

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Stretchy said..
Mike, I dont own a laptop, I do all my posting from iphone or ipad. Speedreader is a terrific application and I'd happily use it if I could load it on these devices.

Does, apple software load on your ipad? if so speed reader should as well. Peter develops it on his apple

Apple doesn't want people making money out of things not sold in our store. Some work from a few years ago, was developed in Ruby on Rails and could be compiled for both Android and Apple. The product still had to go out through the Apple store. Even the testing environment was tightly controlled by Apple. So we sent apk files out to Android beta testers.

GPS Speedreader runs only on systems that support a Java JRE - that means computers, not tablets. In theory, an adaptation to Android might be possible, but it would be a major effort. One issue is that Android thingies tend to have a lot fewer resources (primarily RAM). If we were still dealing with 1 Hz data, that might not be a big issue, but with 10 Hz data, it is. I usually work with computers, not Android, so chances of a port happening are extremely low. In comparison, the effort of adjusting the filters on ka72.com so that it would work correctly on the files linked above is multiple orders of magnitude lower.

For iPhones and iPads, the chance of a port is exactly 0.0. Besides the Apple store issue, Apple has decided to not support (or even allow) Java on these. I have done a little bit of iPhone development using the tools Apple provides, but I'd rather get a root canal without Novocain than do any major project using these tools, and then having to deal with Apple store policies.

Remember we are not playing for sheep stations. The post in question from our Lake Mac sailor was potentially 18 knots peak instead of 13 knots. Is it really a big deal?

Banning KA72 posting would disadvantage a lot of non-technical sailors and really go against the inclusive spirit of the GPSTC.

Has anybody asked Dylan about changing the KA72 filters? His email address is right there on his website if someone can explain the issue to him? www.ka72.com/About/-Who-Is-KA72

Ka72 is such a valuable resource, particularly the tracks, sure some don't like using it but many of us do, it would be a real loss if it's taken away or banned for posting to GPSTC, also would make life harder for the committee in checking results if files aren't posted somewhere. How about we do a fund raising to get any required changes made by holding some sort of comp again through it like the hour of power or NM challenges in the past.

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Dezza said..
How about we do a fund raising to get any required changes made by holding some sort of comp again through it like the hour of power or NM challenges in the past.

I don't think funds is the problem.
This is only my thoughts, but I suspect Dylan wants KA72 to be open to any device. So his filters are set to accommodate less accurate units, If he ups his filters to GPSTC standards a lot of his other clients won't be able to post.

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decrepit said..

Dezza said..
How about we do a fund raising to get any required changes made by holding some sort of comp again through it like the hour of power or NM challenges in the past.

I don't think funds is the problem.
This is only my thoughts, but I suspect Dylan wants KA72 to be open to any device. So his filters are set to accommodate less accurate units, If he ups his filters to GPSTC standards a lot of his other clients won't be able to post.

Perhaps the "Post to GPSTC" button could be greyed out unless the user ticks a box to apply the filters.

I think it will a tragedy if the plug gets pulled on KA72. I like to send my speeds while de-rigging not hours later when I get home and unpack.

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remery said..

I think it will a tragedy if the plug gets pulled on KA72. I like to send my speeds while de-rigging not hours later when I get home and unpack.

100% agree and yes, I predict a mass exodus.

Here's another thought, we choose a Default track type from a list of 17 when uploading. This is remembered for subsequent uploads. What if we had another category "Windsurfing competition" or similar, that applies the filters, "Windsurfing" carries on as previous.

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ka43 said..
As a longtime user of KA72 and an IT dumb arse I think if you excluded the use of KA72 to upload data etc to GPSTC you would alienate a lot of sailors!!! Not everyone is into analysing data, tracks etc. For most its a case of get home, plug in your device and let KA72 do the rest, simples!!
It would be another nail in the coffin, people are getting sick of the elitist mentality that has been creeping in here for quite awhile.
GPSTC was created so everyone could be included.
Yeah I know Im probably not moving with the times but as James said "we are not playing for sheep stations".
I understand where you guys are coming from but look at the bigger picture.
Cheers.

I agree.