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**hpeer** · 02-03-2021, 14:47

Quote:

The additional sounding data is derived from the community edit function.

Several other posts above in the thread have addressed this.

This MAY be true.
But other times they just make it up. It appears to be derived from that just averages between known points, creates a smooth transition between existing soundings. No new soundings.

How to tell which ones are which?

And even if crowd sourced what does that mean? Suppose some Joe runs around in some place with a poorly calibrated sonar and provided data off by a few feet. How do they verify the data?

NOTHING about Navionics sonar data gives me any reason to trust it.

DMF Sailing · 02-03-2021, 19:04

Quote:

Originally Posted by Martkimwat

The additional sounding data is derived from the community edit function. If your boat is properly set up and you have set up the Navionics program on your plotter to allow community edits, it will upload the sonar information from your boat and add that data to all the other boats that have done the same, and that way it slowly builds up a picture of the seafloor from all the boat data combined (won't just use one boats data for obvious reasons) I personally think it is a great idea and probably the way forward, but I expect there will always be naysayers (luddites) who will disagree

Isn't the big problem here the possibility of trolls who deliberately put in bad information just to mess with skippers and their stuff?

Happy to be called a luddite if this concern makes me one. If only all cruisers could form a bond of trust.

**boatman61** · 02-03-2021, 19:10

Quote:

Originally Posted by DMF Sailing

Isn't the big problem here the possibility of trolls who deliberately put in bad information just to mess with skippers and their stuff?

Happy to be called a luddite if this concern makes me one. If only all cruisers could form a bond of trust.

Arr.!!! The return of the 'Wreckers'... Hey Jim lad, spin us a yarn..

DMF Sailing · 02-03-2021, 22:15

Quote:

Originally Posted by boatman61

Arr.!!! The return of the 'Wreckers'... Hey Jim lad, spin us a yarn..

Haha. I was thinking more along the lines of that scene in The Shipping News where the crooked family hangs a lantern on the shoal....

**hpeer** · 03-03-2021, 04:27

Those were “wreckers” Boaty mentions.

Uiu are not a troll, the concern is valid.

At least Navionics should expose how they validate their data. It doesn't have to be intentional misinformation, just stupidity.

And I would love to see where there sonar os based on actual data vs. some algorithm.

Given how careless they have been with the Bahamas problem I don't trust them.

**boatman61** · 03-03-2021, 04:46

Quote:

Originally Posted by DMF Sailing

Haha. I was thinking more along the lines of that scene in The Shipping News where the crooked family hangs a lantern on the shoal....

Its was a career choice on the Cornish coast for a couple of centuries..

cpisz · 03-03-2021, 05:54

The Navionics app is capable of showing government charts as well as the Navionics charts and the crowd sourced sonar charts. It is two clicks to switch between them. I also do not like the user interface as all that much though.

In regards to the crowd sourced data. It is additional information. That is all. I my area I have seen spots where the NOAA charts are grossly outdated. The Navionics charts are closer but the crowd sourced data was the only one that showed the cuts through the bar properly. Use all sources of information that are available and when they disagree use extra caution.

The downside to the crowd sourced data is of course that it is only accurate for places that people actually travel. Nobody travels over the rocks and bars unless you have a flats boat, so there is no data for those locations.

DMF Sailing · 03-03-2021, 06:33

Quote:

Originally Posted by hpeer

Those were “wreckers” Boaty mentions.

Uiu are not a troll, the concern is valid.

At least Navionics should expose how they validate their data. It doesn't have to be intentional misinformation, just stupidity.

And I would love to see where there sonar os based on actual data vs. some algorithm.

Given how careless they have been with the Bahamas problem I don't trust them.

Haha. Haven't read The Shipping News in years. Remembered the scene, not the name of the miscreants.

Thanks, hpeer.

I've been on Other People's Boats where someone, hoping to be helpful, wrote on the clutches the names of the various rigging lines led aft to the cockpit.

Except sometimes, they'd mislabel them.

So an inattentive skipper, in a pinch, thinking he was releasing a reef line, say, was in fact dropping the jib.

You can't underestimate inadvertent stupidity. I wouldn't trust a community-sourced depth contour if one leapt out of the water with a treasure chest and dropped gold doubloons on my deck.

(Then again, I expect there are places in the world where you have to go on less. Perhaps my journey will take me there someday.)

sv_pelagia · 03-03-2021, 07:50

Quote:

Originally Posted by Martkimwat

The additional sounding data is derived from the community edit function. If your boat is properly set up and you have set up the Navionics program on your plotter to allow community edits, it will upload the sonar information from your boat and add that data to all the other boats that have done the same, and that way it slowly builds up a picture of the seafloor from all the boat data combined (won't just use one boats data for obvious reasons) I personally think it is a great idea and probably the way forward, but I expect there will always be naysayers (luddites) who will disagree

While this may be the case for busier areas, we have many places in Canada which see very very few recreational boats (10/year would be a lot for some), and there's no way they have contributed enough sonar information to produce the (supposed) high-detail "sonar" charts Navionics shows for these isolated areas: pure fantasy (simple interpolations of existing limited data).

billcrowley · 04-03-2021, 22:38

Savvy Navvy is a relatively new nav app that seems to be getting very good reviews - though no one mentioned it on this thread. I am ready to acquire a nav app for my tablet as a backup for my Garmin chart plotter at the helm, and am considering this one. Anybody here have experience with it?

Martkimwat · 05-03-2021, 16:26

Quote:

Originally Posted by billcrowley

Savvy Navvy is a relatively new nav app that seems to be getting very good reviews - though no one mentioned it on this thread. I am ready to acquire a nav app for my tablet as a backup for my Garmin chart plotter at the helm, and am considering this one. Anybody here have experience with it?

I have Savvy Navvy, but didn't' mention it because of a conflict of interest. I am one of the crowd funded investors for the start up and also know the developers. I think it is great but then I would say that wouldn't I?