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Old 02-11-2014, 07:38   #1
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Quality of Navionics charts for Bahamas

Hello,

Can anyone comment on the quality of the Navionics charts (Xtraverse) used in iNavX for the Bahamas? We are headed that way this year. We have become fond of the iNavX charts in Belize, where they are the best of a bad lot (Especially compared with the Garmin charts on their own app, which are complete garbage). Since there are no decent paper charts in Belize we've finally gotten over the hump of having paper back up (we have multiple electronic backup instead).


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Old 02-11-2014, 14:12   #2
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Re: Quality of Navionics charts for Bahamas

The only charts that are useful for exact navigation in the Bahamas are the Explorer Charts. These are bundled or available as extras with some charts (Garmin and CMap?), but I do not believe with Navionics.

If you search the threads, I think there was one comparing Navionics to others in the Bahamas and the Navionics were WAY off and incomplete.

This could be completely changed by now, however, since everyone is always updating their products.

Mark
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Old 02-11-2014, 14:40   #3
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Re: Quality of Navionics charts for Bahamas

Quote:
Originally Posted by colemj View Post
The only charts that are useful for exact navigation in the Bahamas are the Explorer Charts. These are bundled or available as extras with some charts (Garmin and CMap?), but I do not believe with Navionics.

If you search the threads, I think there was one comparing Navionics to others in the Bahamas and the Navionics were WAY off and incomplete.

This could be completely changed by now, however, since everyone is always updating their products.

Mark
Except Navionics in the Bahamas which seem to be getting worse! Stay away from Navionics as far as the Bahamas goes. Garmin has the Explorer data on their Bahamas charts. And Explorer charts is the only way to go re the Bahamas.
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Old 03-11-2014, 08:08   #4
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Re: Quality of Navionics charts for Bahamas

Thanks as always Mark. I also have Garmin Bluechart on the iPad and it is pretty underwhelming... Useless in Belize, but it does seem better in the Bahamas. I just did a side by side comparison of Andros Island and the Navionics looks a little better, but not enough difference to gripe about.

I also found an Explorer chip for my veteran RL70CRC chart plotter on eBay so between the three I should be ok.

Charlie


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Old 03-11-2014, 09:54   #5
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Re: Quality of Navionics charts for Bahamas

Garmin may sell the Explorer Charts as an add-on, and not part of their normal package. CMap does it that way.

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Old 03-11-2014, 10:06   #6
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Re: Quality of Navionics charts for Bahamas

[QUOTE=Kamaloha;1669260]Thanks as always Mark. I also have Garmin Bluechart on the iPad and it is pretty underwhelming... Useless in Belize, but it does seem better in the Bahamas. I just did a side by side comparison of Andros Island and the Navionics looks a little better, but not enough difference to gripe about.

I also found an Explorer chip for my veteran RL70CRC chart plotter on eBay so between the three I should be ok.

Charlie

You cannot determine accuracy of charts without being in situ! Just looking at them on a computer tells you little. Navionics has lots of geo referencing problems that are not evident until you are there (wherever you're supposed to be). For example Navionics will actually take your boat over a cay if you are dumb enough to follow their electronic chart.
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Old 03-11-2014, 12:15   #7
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Re: Quality of Navionics charts for Bahamas

Many of the commercially produced charts come from selections of 20 year old charts. Navionics got jobs performed in India by a cartography company. It russiskeTransas digitized papirsøkortene in Sct. Petersburg. The same procedure with BlueChart and C -map.
When Google Earth came, the situation and found that many shorelines were not in line with reality.
Historical chart was drawn official cartographers such as GPS and qualified aerial photographs belonged also discovered that "short and reality" was not consistent.
Many of the commercial charts are corrected and the corrections to the commercially produced charts works pretty but far from satisfactory acordance to Safety at sea.
The satellite images are being misinterpreted. A boat is placed in an island is depicted as a coast projections. A boat between two islands are interpreted as two islands is an island.
Their vektor algorithm leads to islands, etc. first comes with when you zoom in very far and thus lose track of the route. A fatal error that can cause major consequences, since it therefore becomes necessary to constantly zoom in and out.
Many rocks or boats have both been designed as islands.
They buy such. only data for a ten-meter contour and then interpolates to the coast, it provides depth contours that do not correspond to reality. Why sailing on less than ten meters is not advisable.
At lower depth zoom and pan, use sonar constantly and hope !!!

Giuseppe Carnevali which owns Italian Navionics trying to explain away the error:

Giuseppe Carnevali which owns Italian Navionics trying to explain away the errors with: ?? By common practice a product anses very good när har less than 1% failure rate, right beside 99% accuracy. ?? A product with 99.999% accuracy anses closer two science fiction than to reality. ?? Yet with a database (like Navionics') att contains more than a trillion objects som rocks, navigation aids, wrecks etc, 99.999% accuracy still leaves room for 10,000 errors! ?? Therefore let's face it, all charts have the errors.




How showdown to graphical errors in numbers ???
He accepts up to 10,000,000 errors in Navionics charts with 99% accuracy.
That alone provides more than 27,000 corrections from his own mistakes every day for a year.
In addition the many new information each day to be entered in the charts and which will also contain errors coming from drawing and understanding errors.
An impossible task!
What about using the official charts, so could they even made ​​mistakes avoided and the sailors would have a more reliable product.



Navionics has highlighted that they themselves believe that they have a better mapping than the S-57th
They also highlight that they have purchased cartographic information from the Maritime Authority of about a year back, but the agreement is not signed until 6 months later.
When incorporated a clause in the agreement can Sjöfartsverket not comment on whether Navionics cartography really buys from the Maritime Authority or not.

The above is taken from the Swedish insurance company Alandia.


Perhaps it would be opputunt be carried out similar studies include the Bahamas.

Brgds / Harding
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Old 04-11-2014, 22:49   #8
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Re: Quality of Navionics charts for Bahamas

iNavX also supports the nv Bahamas raster charts. They are based on Explorer charts.
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