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Old 24-12-2007, 05:05   #1
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electronic charts

Which electronic charting system (brand) is the most reliable for Pacific ocean and beyond as plotter brands have preferences as to brand of chart supported.
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Old 24-12-2007, 08:06   #2
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Which electronic charting system (brand) is the most reliable for Pacific ocean and beyond as plotter brands have preferences as to brand of chart supported.
None. There are problems with all charts and the Pacific islands are the least accurate given they lack the commercial interest that drives accuracy except in the obvious areas.

To your question I have not seen anything that would make it clear one brand was better than another. Many cruising guides can indicate where some inaccuracies have been found. In those cases the written text description gives you advanced "piloting" information for navigating in close proximity to avoid reefs and other obstacles. Once you can see an island the piloting information is generally more reliable from a guide than a chart. If the errors were known they wouldn't be there.
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Old 24-12-2007, 13:16   #3
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A lot of yacht people have recorded their track (waypoints) through areas where there are known errors, ie. Bligh Waters etc. they share these courses via email giving you much more up to date (safe) information. The trick is to be able to trust the course they have given you when your chart plotter is telling you you are going through the middle of an island. You need get in contact with some of the cruisers who have access to that info. I can't help with that. There will probably be folks on this site who can help.
good luck and Merry Christmas
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Old 24-12-2007, 13:20   #4
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Originally Posted by meyermm View Post
Which electronic charting system (brand) is the most reliable for Pacific ocean and beyond as plotter brands have preferences as to brand of chart supported.
Your question addresses reliability. The answers you have received pertain to accuracy, which is a different thing altogether.

Which did you mean?..or do you mean both?
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Old 24-12-2007, 17:54   #5
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Reliability and coverage - Raymarine seem to push Navionics and Foruno c-map so this begged the question as to which is the better system as all of them rely on the charts
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Old 24-12-2007, 18:04   #6
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One warning about Furuno/C-Map. Not all of Furuno's plotters support all of the features offered by C-Map....I found that out the hard way. While I love my Furno instruments, there advertising is misleading, so do your homework.

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Old 24-12-2007, 19:38   #7
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rleslie I guess that is what I was asking all though I was not very clear I admit.
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Old 25-12-2007, 06:50   #8
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A lot of yacht people have recorded their track (waypoints) through areas where there are known errors
It would be advised that before you rely on any "way points" you get from others that you be sure of the map base coordinate system they used to collect them. You also risk transcription errors on either their end or yours. It just underlines that you never can escape the fact that information like this is never 100% accurate.

Now consider a chart created from many sources. You have a GPS with WASS accurate reception but a chart that is not as accurate as you instrument. Your additional GPS accuracy is worthless without a matching chart just as accurate. The navigational error is the error of the both added together.

Acquired GPS points might be 100 yards off from your current position and you could never know. You double the GPS error when you attempt to hit a recorded location with your GPS since the time of collection was not the time you arrived. You never can know how accurate the data was nor how different your receiver is at that time.

From a navigation perspective 100 yards is pretty darn close when coming 5,000 miles away. You would clearly jump for joy extolling how you were perfectly accurate with your arrival. From a piloting perspective a coral head is too close to trust a GPS point. The context of how you apply information has different meanings. Nothing illustrates the point better than GPS navigation.
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Old 25-12-2007, 17:38   #9
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meyer, if there are particular places that you want to go to, you might want to contact their authorities and ask them "What charts, chart sources and chart datums are most reliable for your country? If any?"

And even then, rely on the electronics but stay well clear of anything except in daylight, using your own eyes or local knowledge to make sure of it.

Perhaps the folks at noonsite.com could be interested in adding that kind of information to the databases they keep for different countries.
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Old 27-12-2007, 06:12   #10
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all the replies have been helpfull and given me a basis to work on
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