Navionics charts (maybe all chartplotter charts)

[Pelagic]

Originally Posted by colemj

It depends on where you are. Certain cartographies are better in certain areas. ......
In other parts of the world different cartography shines/sucks. ....Mark

I have heard that from many others to Mark....

So the key question?

Does a Cartography accuracy list per region exist that would help a sailor decide which program and supporting hardware he should buy for his given Region?

If not.....we should start one and get real time reports from actual users.....What a great resource that would be in planning!

[belizesailor]

Originally Posted by Pelagic

I have heard that from many others to Mark....

So the key question?

Does a Cartography accuracy list per region exist that would help a sailor decide which program and supporting hardware he should buy for his given Region?

If not.....we should start one and get real time reports from actual users.....What a great resource that would be in planning!

Would be a good idea. Maybe Active Captain comments?

I've tried to notify Navionics about chart inaccuracies before and got nothing but scripted corporate speak in response. Clearly they were not interested.

[colemj]

Originally Posted by roland stockham

That is why the first rule of navigation is to fix your position by 2 INDEPENDENT sources. Checking to GPS based positions against two different electronic charts or a paper chart is better than nothing but all your position fixes are still based on GPS co-ordinates. The answer is to make sure that before you do anything critical like a night harbour entrance or rounding a point close in you check you position by compass fix and/or radar. This confirms you position and tells you the current local GPS error. Once you confirm the error you can then put more reliance on GPS for the rest of those maneuvers. There has been significant loss of life and vessels both commercial and pleasure due to over reliance on GPS. It is also worth checking the source data for charts before using them, you will be surprised how many are still based on a lead line survey from a sailing ship in many cruising areas. I am not talking remote areas either, I have seen dates in the 1800's in the Bristol channel and Irish sea!

I don't understand this. Unless one is a tin-hat aficionado, the GPS position is going to be one's accurate position to a practically high degree. There is little to doubt about this. Any other way of gaining one's position is just going to introduce significantly more error. I can't think of a single incident where anyone came to grief because of relying on their GPS position. Maybe long ago during the days of selective availability, but even then, that was probably higher accuracy than any other method. There is no way celestial positioning will even come close, and LORAN never achieved the accuracy and precision of GPS.

Mark

[Pelagic]

Belieze Sailor....Glad you like the idea.

Once we agree on a simple format questionnaire I will start a new Thread.

Very open to ideas/ guidance on best way to do this

Suggested title:
BUYER'S GUIDE to Electronic Charts by Region

I am thinking more of a world review by region... where users/buyers of recent chart data have actual user experience.

For example
Western Pacific and South China Sea.

Which system has BEST:
1 ACCURACY
2 HARBOR AND ANCHORAGE DETAIL
3 OTHER FEATURES
4 COMMENTS /COMPARISONS
5 Recommended ECS program by product name and Region Title. C-MAP, NAVIONICS etc...



Active Captain is great but serves mostly USA and is perhaps too detailed to provide a Buyers Guide by worldwide Region

[clownfishsydney]

We have Navionics Gold for Australia. It is mostly accurate but some places are not. For example, at Lady Musgrave Island on the Great Barrier Reef, if you entered the lagoon via the channel relying on the chart plotter you actually would hit the edge of the reef. At Pancake Creek, you go through the headland on the chartplotter when entering via the channel. Hook Island in the Whitsunday Islands also has some incorrect mapping on the north-eastern corner. I would not trust for night entry that is for sure.

OpenCPN running Google Earth was accurate for all of the above.

[TranceNT]

A general comment and query relating to regional Navionics chart.

In the Australia and New Zealand instance, 'community edits' seem to be improving the chart updates, both in bathymetrics and location accuracy.

Does this community engage in uploading logs from suitable equipment?

[Pelagic]

Originally Posted by clownfishsydney

We have Navionics Gold for Australia. It is mostly accurate but some places are not. For example, at Lady Musgrave Island on the Great Barrier Reef, if you entered the lagoon via the channel relying on the chart plotter you actually would hit the edge of the reef. At Pancake Creek, you go through the headland on the chartplotter when entering via the channel. Hook Island in the Whitsunday Islands also has some incorrect mapping on the north-eastern corner. I would not trust for night entry that is for sure.

OpenCPN running Google Earth was accurate for all of the above.

Thanks...that is a great example of what I am looking for.....
By chance, were you ever able to compare with other EC's like C-MAP?

Google is great but it does not give soundings

[Pelagic]

Should we start a specific Thread for each Region so that it is easier to find and update.??

Keep the same format and questions... But region specific??

[clownfishsydney]

Other Navionics users had similar problems to us. Others using different charts were generally okay for these, but did talk about other places where they were inaccurate.

[Mirage Gecko]

Originally Posted by clownfishsydney

We have Navionics Gold for Australia. It is mostly accurate but some places are not. For example, at Lady Musgrave Island on the Great Barrier Reef, if you entered the lagoon via the channel relying on the chart plotter you actually would hit the edge of the reef. At Pancake Creek, you go through the headland on the chartplotter when entering via the channel. Hook Island in the Whitsunday Islands also has some incorrect mapping on the north-eastern corner. I would not trust for night entry that is for sure.

OpenCPN running Google Earth was accurate for all of the above.

Intersting comments.
As a comparison I only have the cheap version on IPad and have been in and out of Pancake Creek using only the IPad 8 times in the last two years following exactly the Magenta line and have gone now where near the hard stuff.Just checked my track out of there from just a few weeks ago and with the exception of my chosen course the Magenta was spot on.Personally I am continually amazed at the accuracy of the program
especially when making a passage and finding solitary beacons and markers where they are supposed to be.

[skipgundlach]

At the risk of diverting the thread I started, as OpenCPN is one of the three ways I back up my eyeball mark 1.0 manual unit, how do you put google earth onto OC at sea?

I do it on my computer, with a puck GPS, so no cell connection/WiFi, usually (depending on where we are I may have both)...

Actually, I need to know how to use it at all (get GE onto OC), but if I =did= know how, don't see how I could use it at sea...

[belizesailor]

Just creating a thread is an easy way to start. Maybe put area of coverage as first line so that its easy to find. And first sticky post should be standard format template for posting.

I would open it up to good and bad so that those with a given echart brand can know where its accurate and not.

[belizesailor]

Originally Posted by skipgundlach

At the risk of diverting the thread I started, as OpenCPN is one of the three ways I back up my eyeball mark 1.0 manual unit, how do you put google earth onto OC at sea?

I do it on my computer, with a puck GPS, so no cell connection/WiFi, usually (depending on where we are I may have both)...

Actually, I need to know how to use it at all (get GE onto OC), but if I =did= know how, don't see how I could use it at sea...

Best to start a separate thread on that. That way not only do you not derail this thread, but you will likely get more responses. This thread is heading in a good direction I think, so I would let this train keep a rollin.

[colemj]

Originally Posted by skipgundlach

At the risk of diverting the thread I started, as OpenCPN is one of the three ways I back up my eyeball mark 1.0 manual unit, how do you put google earth onto OC at sea?

I do it on my computer, with a puck GPS, so no cell connection/WiFi, usually (depending on where we are I may have both)...

Actually, I need to know how to use it at all (get GE onto OC), but if I =did= know how, don't see how I could use it at sea...

Yes, start a new thread (this topic is deserving of that), but do a search first. The short answer to part of it is that you can cache GE data to be used off-line.

Mark

[skipgundlach]

Originally Posted by colemj

Yes, start a new thread (this topic is deserving of that), but do a search first. The short answer to part of it is that you can cache GE data to be used off-line.

Mark

Cool. I'll do that, and look for your answer re validity of GE from a non-downloaded location (we're not in Kansas, any more, e. g.)