The Electronic Charting "Zoom Problem"

[transmitterdan]

ENC vector charts are not works of art. They are not intended as works of art. They are intended as navigational tools. As such they convey lots of information without lots of stuff you don't need right now. But there is a lot of information buried within the data and you can see it with a click or push of a button. There is vastly more textual information in an ENC chart than can ever be shown on a raster or paper chart.

I use them for planning and actual navigation in US waters. So do nearly all commercial vessels. Unfortunately there seems to be a conspiracy between the chart companies and the chart plotter companies. Most recreational chart plotters don't support the free ENC charts. That is changing but slowly. O is hands down the best ENC chart plotter I can afford.

[Dockhead]

Originally Posted by transmitterdan

ENC vector charts are not works of art. They are not intended as works of art. They are intended as navigational tools. As such they convey lots of information without lots of stuff you don't need right now. But there is a lot of information buried within the data and you can see it with a click or push of a button. There is vastly more textual information in an ENC chart than can ever be shown on a raster or paper chart.

I use them for planning and actual navigation in US waters. So do nearly all commercial vessels. Unfortunately there seems to be a conspiracy between the chart companies and the chart plotter companies. Most recreational chart plotters don't support the free ENC charts. That is changing but slowly. O is hands down the best ENC chart plotter I can afford.

Looks pretty good -- though pretty much like CM93 or Navionics. What would be more interesting would be to compare what they look like, in comparison to CM93, as you zoom out -- do they retain more detail? In any case, you're lucky to get them free. Are they officially "For Navigation"?

[transmitterdan]

From the US web site:

Permitted Use
The NOAA ENC® files are intended for navigational use. They are 
intended to be used in their electronic form only. You may download, 
use, and redistribute them without restriction, and without payment 
to NOAA, except as noted herein.  They may be used to meet federal 
chart carriage regulations published in the Code of Federal Regulations. 
On November 15, 2005, the regulations were as stated below. These 
regulations may change, and mariners are advised to check the 
Code of Federal Regulations for their current status.

You can read more here: ENC Downloads

[Dockhead]

Originally Posted by transmitterdan

From the US web site:

Permitted Use
The NOAA ENC® files are intended for navigational use. They are 
intended to be used in their electronic form only. You may download, 
use, and redistribute them without restriction, and without payment 
to NOAA, except as noted herein.  They may be used to meet federal 
chart carriage regulations published in the Code of Federal Regulations. 
On November 15, 2005, the regulations were as stated below. These 
regulations may change, and mariners are advised to check the 
Code of Federal Regulations for their current status.

You can read more here: ENC Downloads

I'm going to download all of them as soon as I'm on a non-metered Internet connection. How great it is that these are available for free -- would that the rest of the world did the same.

[Dockhead]

Even more relevant controls in OpenCPN I didn't know about:



Notice the "Reduced Detail at Small Scale" control.

What do all these "Mariner's Standard" controls mean?

[RhythmDoctor]

Originally Posted by Dockhead

Even more relevant controls in OpenCPN I didn't know about:

Attachment 96766

Notice the "Reduced Detail at Small Scale" control.

What do all these "Mariner's Standard" controls mean?

Yes, this is exactly why so many of us have been telling you to learn to use the program's current capabilities before asking for new capabilities to be added. Please consult the user manual for what the controls mean. Many of us put long hours into writing the manual so that we don't have to answer so many questions here in the forum.

Note that there is a lot of complexity in the dialog that you posted - a lot of power to filter out clutter. But one man's clutter is another man's treasure. And therein lies the danger of vector charts. That is why I prefer to use raster charts for initial planning - because professional cartographers have made sure the really important stuff is shown, instead of a relatively unsophisticated user (me) accidentally unchecking a box that should have been left checked.

[Dockhead]

Originally Posted by RhythmDoctor

Yes, this is exactly why so many of us have been telling you to learn to use the program's current capabilities before asking for new capabilities to be added. Please consult the user manual for what the controls mean. Many of us put long hours into writing the manual so that we don't have to answer so many questions here in the forum.

Note that there is a lot of complexity in the dialog that you posted - a lot of power to filter out clutter. But one man's clutter is another man's treasure. And therein lies the danger of vector charts. That is why I prefer to use raster charts for initial planning - because professional cartographers have made sure the really important stuff is shown, instead of a relatively unsophisticated user (me) accidentally unchecking a box that should have been left checked.

In other words, RTFM

Fair enough. I will continue studying it.

When you consider whether or not to bother answering someone's question, however, a simple question which could have easily been answered by manual-reading, don't forget how many of us on here have explained 93 times to some newbie how to put a snubber on . . .

That's also part of it, in my opinion, I mean, being part of this community.

Yes, I now fully get your "professional cartographer's view" versus "my own check-box generate view" idea. I think this is a really important point.

I'm going to play with the S63 charts of U.S. waters, but I think I'm going to have to bite the bullet and acquire some NV raster charts of the Baltic.

[RhythmDoctor]

By the way, some of your ideas have gotten traction as being really useful, so I wasn't suggesting that you stop making any suggestions. As you learn to tweak the controls better, you'll get an idea which things can already be done with existing features. And as you see how complex some of these things can be, you'll also get an idea which suggestions might be more trouble than they're worth.

[RhythmDoctor]

Originally Posted by Dockhead

In other words, RTFM

Fair enough. I will continue studying it.

One of the nicest things about OpenCPN is that it is intuitive enough that many can do useful work without reading the manual. But, unfortunately, the level of vector chart tweaking that you want requires the use of advanced features that cannot be used safely without consulting the documentation. As they say, "Be careful what you ask for."

[transmitterdan]

Originally Posted by Dockhead

I'm going to download all of them as soon as I'm on a non-metered Internet connection. How great it is that these are available for free

Err, they aren't exactly free to foreigners. If a US citizen visits your boat they are entitled to one Sapphire martini as recompense. Said tariff to be eliminated when said countrymen are successful in convincing their own politicians to free their country's charts from bondage.

You don't have to get them all. Just get Region 15 which is the Pacific Northwest. Some of the finest cruising grounds in the world. Like the Baltic except all the foreigners speak English (or at least it can be understood by the English).

[Dockhead]

Originally Posted by transmitterdan

Err, they aren't exactly free to foreigners. If a US citizen visits your boat they are entitled to one Sapphire martini as recompense. Said tariff to be eliminated when said countrymen are successful in convincing their own politicians to free their country's charts from bondage.

You don't have to get them all. Just get Region 15 which is the Pacific Northwest. Some of the finest cruising grounds in the world. Like the Baltic except all the foreigners speak English (or at least it can be understood by the English).

Small corrections -- not one martini, but as many as you can drink -- that's sacred.

And not Sapphire -- we have Hendrick's for special guests, especially those bearing charts

And lastly I'm not a furriner. Learned to sail in Galveston Bay and spent many years cruising in SW Florida.

My mother lived out her last decade in Portland, OR, so I used to travel frequently to the PNW. Unfortunately I have seen it only from land.

[Dockhead]

Originally Posted by RhythmDoctor

One of the nicest things about OpenCPN is that it is intuitive enough that many can do useful work without reading the manual. But, unfortunately, the level of vector chart tweaking that you want requires the use of advanced features that cannot be used safely without consulting the documentation. As they say, "Be careful what you ask for."

Yes, I'm gathering that -- it's like one of those multi-level computer games. I've been very surprised by the complexity I've found beneath the innocent-looking surface. I'm humbled and will crack the books.

[rgleason]

Back to what I think the problem is. Cartographers used a simple technic to represent very smalll islands on large charts. The object is enlarged naturally in the action of showing it, because they knew something was there or approximately there.
Perhaps use a type of marker at larger scales, or jusr enlarge the objects at larger scales so they can be seen. Its a bit messy programatically, but maybe there would be some simple way to multiply land pixels that are small os scale vector land masses that have a relatively very small area?

Sent from my SCH-I545 using Cruisers Sailing Forum mobile app

[Dockhead]

This analysis of the Costa Concordia accident is really interesting:

https://maddenmaritime.files.wordpre...alaccident.pdf

Some of the concepts, like Bridge Resource Management, are more applicable to us than might seem at first glance.

The "Electronic Charting Zoom Problem", which some people deny exists, is mentioned as one of the factors in the accident:

"Another potential usability issue might have contributed to “hide” the underwater rock to the eyes of the officers (fig.15a and 15b). This relates to the clarity of electronic vector charts on navigational display. Spot soundings overlapping with depth contours and other cartographic features are the norm on ECDIS and ECS, and the dynamic customization of the various layer of information at best requires a considerable cognitive 16 effort. In the worst cases important features becomes unreadable, compromising the situational awareness of the OOWs. Comparing the paper chart with the vector chart of Giglio Island (fig.16 a, b), it appears evident
that the art of cartography got lost in translation from paper to vector charts."


The last bit is a subtle and important remark, reminding me strikingly of this comment by RythmDoctor:

"Note that there is a lot of complexity in the dialog that you posted - a lot of power to filter out clutter. But one man's clutter is another man's treasure. And therein lies the danger of vector charts. That is why I prefer to use raster charts for initial planning - because professional cartographers have made sure the really important stuff is shown, instead of a relatively unsophisticated user (me) accidentally unchecking a box that should have been left checked."


I have been playing with the vector chart controls in OpenCPN, and with the raster charts I bought.

So far, I can't get dramatically more useful views of vector charts, using the controls. Applying blanket rules to the detail shown does not really help -- the "professional cartographer's art" is needed, not a mechanistic rule. Some professional cartographer devised the layers or default rules used in vector charts. Maybe the ENC charts -- designed for larger, higher resolution displays -- will be better than the Navionics charts I have. But so far I can't get my vector charts to display in a way that is really suitable for planning in complex water.

So I am starting to believe that you need raster charts for that, as Rhythm Doctor says. For chart plotting underway, vector charts look better, but for planning, raster seems unbeatable.

I can say that I've now reached the point where the official UK raster charts on OpenCPN with a large high res display are better for me for planning than paper. Yes, really. This is a watershed for me. I still can't quite see as much detail (maybe with a 4k display at the nav table), and you can't put down a Portland Plotter and pencil, but the ability to instantly switch between different charts with the "piano keys" is something you can't duplicate with paper, and there are many tools which are laborious to emulate on paper, like transferring routes to the main nav system.

So I guess I'm going to bite the bullet and acquire the expensive NV raster charts for the Baltic. The company does not sell electronic charts without paper -- you automatically get the paper charts too. So I won't have to give up paper altogether.


I think there's still room for some feature OpenCPN which would preserve the display of actual hazards (as opposed to other details) in some symbolic form at zoomed-out views of vector charts, as we've been discussing.

[bcn]

Dockhead,

as the information about hazards is available from the vector charts even if those are not visible/not shown a "route checker" which uses this information would be a feature I would like to see in a future version.

In the planning stage and as "hazard 2nm ahead" pop-up option when underway.
And this using the safety contour defined for the vessel or that voyage.

No cluttering of the display and using the existing information.

Hubert