Försäkringsbolaget Alandia har i ett pressmeddelande varnat för Navionics digitala sjökort. Anledningen är att Alandia har funnit att viss sjökortsinformation endast framträder vid kraftig inzoomning i navigatorn. På DagensBåtliv.se är vi inte säkra på att felet ligger i sjökorten. Vi tror att det har att göra med navigatorns inställning och hur och när navigatorn väljer att plocka fram all sjökortsinformation runt ett grund.
DagensBåtliv.se har skrivit om Alandias påstående i en tidigare artikel, nedanför denna. Börja gärna läsa den om du inte redan tagit del.
Navionics grundare Giuseppe Carnevali svarar här på Alandias kritik:
Alandia "used" SSRS (Swedish Rescue) boats to test some electronic charts, then without their sponsorship created a sensational and misleading press release, in order to generate a lot of noise and portray itself as guardian of safety. But safety is something else.
Navionics' founder Giuseppe Carnevali tells his view on the safety of electronic charts.
Alandia omitted most of the truth in its press release:
- that SSRS simply loaned the boat to them, but did not sponsor the press release
- that the hazards are NOT missing in the charts, but shown at detailed zoom levels as per standard chart scale
- In many plotters, the user can select the amount of detail displayed at a zoom level (low, medium, high)
- Navionics provided Alandia with a prototype of a chart with different default zoom settings (not different content), which they verbally said they liked, but did not report on
- and reported a quote of Navionics’ representative that, being taken out of its context, has changed the meaning of his statement
So let me address the issue of safety of electronic charts from a professional point of view.
First and foremost what can we see in them.
Our good ol' paper chart was at least as big as a 50-inch screen, and never failed, even in the absence of electricity.
It is impossible to squeeze the content of a 50-inch display in a 5-inch display of a plotter without creating a big black blob of unreadable clutter.
The only way to make it readable is to selectively display data at different zoom levels, and to have two displays, or a least a split screen, one showing the best possible detail and the other showing an overview for situation awareness.
Some plotters allow users to set the amount of data displayed at different zoom levels, and Navionics is changing the default settings to reflect market feedback.
Proper use of such features is highly recommended because it improves the visibility of details, but still does not eliminate the need to use both a detailed zoom level and an overview. This is not different from proper use of paper charts: always have at hand both the most detailed chart and an overview chart.
Furthermore it is not rare for the electric system of a boat to fail. If that happens, it is unsafe and unthinkable to go back to a paper chart and sextant. Always have a backup plotter with an independent power source, or at least a phone or a tablet with a good app as a backup.
Then comes the chart itself.
Nautical charts are a complex product to make and, independent of whether they are on paper or electronic media, have always been, and continue to be, liable to error
Electronic charts are far safer than paper and sextant, but boaters sometimes tend to over-rely on them, expecting them to be absolutely perfect. It does not work like that.
Reality is that all nautical charts have errors, and even more importantly they are NOT made for blind navigation: one should not think that electronic chart equates to instrumental navigation, therefore equates to blind navigation, especially in narrow and treacherous waters.
I am both an airplane and helicopter pilot and a licensed skipper, so I am familiar with the difference between instrumental navigation in the air and at sea.
In the air, instrumental navigation relies on ground-based control towers that ensure safe separation between aircraft, and on a series of ground-based instruments like radar, transponder, VOR and ILS that can guide aircrafts through pre-defined and pre-tested routes that keep them safely away from hazards. When aircraft do not fly along the pre-defined and pre-tested routes, they can only fly in full visibility to stay away from hazards.
At sea, most hazards are invisible because they are under water, and there are no ground-based guidance instruments, no control towers, and no pre-defined and pre-tested routes: anybody can go randomly anywhere. Charts of marine hazards exist, but sometimes they are inaccurate because they are based on old surveys, when instruments were not as accurate as today, and sometimes contain outright errors. This is why blind instrumental navigation at sea is simply not possible, and safe navigation requires skill and judgment in using multiple sources of information, including charts at different zoom levels.
So let's talk about chart errors.
By common practice a product is considered very good when it has less than 1% failure rate, which means 99% accuracy.
A product with 99.999% accuracy is considered closer to science fiction than to reality.
Yet with a database (like Navionics') that contains over a billion objects such as rocks, navigation aids, wrecks etc, 99.999% accuracy still leaves room for 10,000 errors!
No chart, whether made by Navionics or its competitors or any Hydrographic Office, can avoid this mathematical rule.
Therefore let’s face it, all charts have errors.
The issue then becomes: how can we best correct them, and make sure that boaters use the corrections.
It is well known that Hydrographic Offices have limited tax money available to them, and they simply cannot afford to deploy hundreds of thousands of surveyors at sea to make corrections.
It is equally well known that even when errors are found and notices to mariners are issued, months or years later, boaters do not apply the notices to mariners to their charts because it is too tedious.
Modern technology makes it possible for millions of boaters who are at sea every day to easily make corrections to their charts as soon as they spot a problem, and then distribute the correction in real time to all other boaters, without requiring them to do any work at all to update their charts.
This is commonly done by scores of organizations like Wikipedia and others, and this is what is done by Navionics through its unique Community Edits and Freshest Data programs: if you have a Navionics app on your phone or tablet, in less than 30 seconds you can move a buoy or add a rock, and in less than 5 minutes that same correction shows up on everybody else's chart automatically, no manual intervention at all being needed.
To avoid malware, all community edits are kept in a separate and well identified layer, so that the integrity of the database is ensured.
Furthermore, community edits are policed by the community itself, because boaters can check and correct the edits of other boaters, and can report abuse. The system works so well that in several years, after more than half a million edits made by over 100,000 boaters worldwide, only one single case of abuse has been reported, and the culprit has been promptly disabled from using the Navionics app at all, let alone make any more edits.
Today there could be even more than that, since every boat has a sonar and continually measures the depth of water; but unfortunately all that data get thrown away.
Navionics now provides a very simple way to save that data and help improve the nautical chart through the SonarChart program: within a week the sonar data are processed by our expert cartographers, and every day we publish a new edition of our SonarCharts improved with your data as well as the sonar data from the entire boater community.
If anybody has a plotter but not a tablet, he can update his chip every day by simply plugging the chip in a computer: the computer will automatically connect to the Navionics website and download the Freshest Data by itself.
Before the summer Raymarine and Navionics will launch a yet more innovative system, whereby the Raymarine plotters connect directly to the Navionics app via wi-fi, synchronize routes and waypoints, upload the sonar data and download the chart updates: all automatic, you do not even need to bring the chip home to plug it in a computer!
Long gone are the days of tedious notices to mariners sent by post on a slip of paper!
Unfortunately Sweden is one of very few countries in the world that prohibits the SonarChart program at sea, but they do allow it in inland waters, they do allow community edits everywhere, and they surely do strongly recommend chart updates.
As a picture is worth 1,000 words, let's see some practical examples in the attached .ppt: errors in the official S57 charts that have been corrected by the community, and the chart of a Swedish lake improved via the SonarChart program.
Keep in mind that almost 7,000 community edits have been made in Sweden, of which about 1,500 of rocks, wrecks and obstructions alone.
Se bifogad Powerpoint, *Klicka*
In conclusion it is mathematically certain that all charts have errors, and therefore must be used with skill and caution instead of blindly.
No chart manufacturer, public or private, nor any maritime safety agency, would dispute this statement.
In order to reduce errors, boaters have two choices: pay a lot more tax to better fund the Hydrographic Offices, or engage in community edits and keep their charts continually updated.
If Alandia really wanted to promote safety, instead of engaging in what one could interpret as marketing stunts, they would encourage boaters to participate in community edits, keep their charts up to date with freshest data, use all zoom scales, have a proper backup, and use any charts with caution.
Navionics: we start where the road ends
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