Tablet chartplotting- not Navionics

[jdc]

I'm with both AntarcticPilot and Roberto on this, but my Raymarine chart plotter can not use admiralty charts. Raymarine - for some bizarre reason wholly at odds with the needs of its customers - force one to use charts from Navionics or the rather poor selection from Imray (In UK waters, it's different in the US). But I want to use Admiralty raster charts and add the Antares ones also - all of which I've bought and paid for - but it's not possible. Of course I can (and sometimes do) run a completely separate system on a laptop, on which I can run AC and/or Antares charts, but its a pita when I already have an expensive chart plotter. Grr

 

[dunedin]

I'm with both AntarcticPilot and Roberto on this, but my Raymarine chart plotter can not use admiralty charts. Raymarine - for some bizarre reason wholly at odds with the needs of its customers - force one to use charts from Navionics or the rather poor selection from Imray (In UK waters, it's different in the US). But I want to use Admiralty raster charts and add the Antares ones also - all of which I've bought and paid for - but it's not possible. Of course I can (and sometimes do) run a completely separate system on a laptop, on which I can run AC and/or Antares charts, but its a pita when I already have an expensive chart plotter. Grr

Not sure you will find many chart plotters that can run raster charts - like Antares or any others. The display software needed to present raster charts is very different from that needed to display vector charts (and electronic raster charts are likely to become less common in future). Hence I suspect the recent capability of Raymarine Lighthouse software based plotters to display Imray raster charts is quite rare (particulary as Raymarine starts to roll out its own Lighthouse branded charts).

But I treat this as a positive opportunity - going into tricky Scottish anchorages I am happy to be running BOTH Navionics on the plotter AND Antares (plus UKHO raster) on my iPad (tablets IMHO massively better than a laptop for this role). The helm has sight of the plotter, and skipper as navigator standing up using eyeball plus iPad.

 

[lustyd]

For me raster charts can't be killed off quickly enough. I want to be the one in charge of what I see at a given zoom, and I prefer my display doesn't change dramatically when the sheet is swapped out for a different one. From a pure technology point of view it makes no sense to render the chart ahead of time, and takes considerably more resources to do so at all stages.

 

[Pye_End]

For me raster charts can't be killed off quickly enough.

Why would you want to deny those of us who prefer raster charts, and impose your own preferences? Surely their existence does not degrade your own choice of charts?

 

[lustyd]

Why would you want to deny those of us who prefer raster charts, and impose your own preferences? Surely their existence does not degrade your own choice of charts?

I'm not that bothered really, it's just an unnecessary thing that needs to be checked and learned and explained. It's only there for legacy reasons rather than adding any kind of useful advantage. Eventually support will need to drop because otherwise someone needs to maintain and patch the code which supports them and the chart companies will need to keep producing raster charts from their vector data. We've already seen the Admiralty move to custom charting printed on demand instead of folios and I'd have to assume raster charts will be on the kill list soon.

 

[requiem]

Eventually support will need to drop because otherwise someone needs to maintain and patch the code which supports them and the chart companies will need to keep producing raster charts from their vector data. We've already seen the Admiralty move to custom charting printed on demand instead of folios and I'd have to assume raster charts will be on the kill list soon.

Indeed, on the US side this has already happened. NOAA moved to print on demand about a decade back, and the last few NTMs now include lists of raster chart cancellation dates; the plan is that by 2025 all US raster charts will have been cancelled. The tile service that provided seamless raster data has also been shut down.

 

[Pye_End]

It's only there for legacy reasons rather than adding any kind of useful advantage.

Not according to Tom Cunliffe - How to use vector charts safely . Having also used both I would agree with him.

 

[lustyd]

Not according to Tom Cunliffe - How to use vector charts safely . Having also used both I would agree with him.

Confusing a vector chart issue with a configuration issue is not a reason to reject vector charts. Those raster charts are literally just print outs of vector information which TC claims are then scanned to produce raster charts. He's entirely wrong, of course, the raster charts are just rendered vector charts which are saved as a bitmap. Someone still had to decide to include that reef on the render, and people can choose to show that same reef with a vector chart. If not, then it's the fault of the plotter and software, not the chart. The difference is that raster charts will only ever show what was included in the render.

 

[AntarcticPilot]

Confusing a vector chart issue with a configuration issue is not a reason to reject vector charts. Those raster charts are literally just print outs of vector information which TC claims are then scanned to produce raster charts. He's entirely wrong, of course, the raster charts are just rendered vector charts which are saved as a bitmap. Someone still had to decide to include that reef on the render, and people can choose to show that same reef with a vector chart. If not, then it's the fault of the plotter and software, not the chart. The difference is that raster charts will only ever show what was included in the render.

Exactly so. All cartographic work these days is done in vector formats and has been for many years. In fact, in all my career (i.e. since 1979!), I don't think I've seen raster ever being used as the working medium for cartographic work, except for very specific types of data. A raster chart is merely the equivalent of doing a print command to a specific medium. There are data that are best handled in raster form - satellite images, for example - but these are not used in mainstream charting. Even when we used image data (aerial photos and satellite images) we embedded them in a vector dataset. Raster is an output, not the data itself. It's also a very inflexible output, with major drawbacks..

UKHO switched to vector charting in the 1990s; but they weren't using raster before that - they used drafting pens and peel coats!

 

[Pye_End]

The difference is that raster charts will only ever show what was included in the render.

It is precisely this that makes them so useful. On raster, relevant information to the scale is included, but thoughtfully de-cluttered. Team Vestas Wind was lost because the Vector charts did not show important information at the scale they were using, which would have been on a raster chart. Ok, they could probably have pressed a few buttons to get more info, but they didn't, and if they did the screen may have got too cluttered for the user to quickly assess the critical information.

 

[requiem]

It is precisely this that makes them so useful. On raster, relevant information to the scale is included, but thoughtfully de-cluttered. Team Vestas Wind was lost because the Vector charts did not show important information at the scale they were using, which would have been on a raster chart.

Having just checked the UKHO ENC for that area, the reef is quite clearly marked even zoomed out to 1:15,000,000 scale. Looking at the quality information in the chart, I see that I should also allow it a wide berth.

The linked article conflates a few issues, as you could just as easily say it's comparing 3rd party charts to official charts rather than raster charts to vector charts. Similarly, ENCs have their own intended scales just as raster charts do. Not knowing how to use ENCs is really not much different from a non-sailor not knowing how to work out their position on a paper chart.

 

[dunedin]

It is precisely this that makes them so useful. On raster, relevant information to the scale is included, but thoughtfully de-cluttered. Team Vestas Wind was lost because the Vector charts did not show important information at the scale they were using, which would have been on a raster chart. Ok, they could probably have pressed a few buttons to get more info, but they didn't, and if they did the screen may have got too cluttered for the user to quickly assess the critical information.

The issue there is not with Vector charts - it is with the rules the software developers apply when summarising data. It is not clear what precise product Vestas Wind was using when it hit the reefs. And it may not have been a commercial chart plotter, indeed I don’t know if it was a tool intended for navigation /pilotage as opposed to race tactics, who knows?
But it seems bizarre that anybody should summarise an area of chart and not show the shallow water and indeed islets. Surely the zoom can easily be done on a cautious basis - and show the highest obstacle in the area (ie shallowest depth or biggest drying height) rather than simply averaging. The design/ maths for this is trivially simple.
So IMHO there is no inherent issue with Vector charts (which are I believe the only electronic type approved for commercial ship navigation, in form of ENCs), if display software safely designed.
Indeed I have looked at the precise area Vestas Wind hit with things like Navionics online viewer, and when zooming down the dangers are still clearly shown.

 

[Roberto]

After the Vestas accident Navionics stated they included those shoals even at little scales; they forgot a few other bits and pieces though
This is navionics for the central Atlantic, CMAP -at least "that" cmap- is identically blank, of course they are non commercial editions.



This is a raster NGA chart, tiny rocks/islands are shown, as well as sea mounts, the continental shelf, etc etc

 

[Buck Turgidson]

After the Vestas accident Navionics stated they included those shoals even at little scales; they forgot a few other bits and pieces though
This is navionics for the central Atlantic, CMAP -at least "that" cmap- is identically blank, of course they are non commercial editions.

View attachment 128417

This is a raster NGA chart, tiny rocks/islands are shown, as well as sea mounts, the continental shelf, etc etc
View attachment 128418

F de N islands are not tiny.

 

[jdc]

Navionics, unless one zooms in, also leaves out the Ilhas Selvagens which are on the direct path from Madeira to Grand Canaria - a set of islands with lighthouse and a very frequently travelled passage! It's true that such bad decisions on scaling / decluttering are not inherent to vector data, but seem to be commonplace with Navionics. Hence I like to have raster charts as well as - not instead of - vector.

My Raymarine displays raster charts ok, its the availability of them in UK waters which is poor. And I think that vector vs raster debate is pointless for very detailed charts covering a tiny area such as the Antares chartlets: they are to be viewed at only one scale. And I'd like the ability to select them on my plotter.

 

[lustyd]

After the Vestas accident Navionics stated they included those shoals even at little scales; they forgot a few other bits and pieces though
This is navionics for the central Atlantic, CMAP -at least "that" cmap- is identically blank, of course they are non commercial editions.

This seems to be misunderstanding the point quite badly. If you're comparing Navionics and CMAP that means you are not using their choice of detail. It's the chart reader/renderer which chooses what to show at a zoom level with vector charts, not the chart producer. There is no "zoom level" on a vector chart, it's all the detail all the time, some of which is filtered by the plotter/app. Raster charts, by contrast include only the data they were rendered with and you can zoom in and out and it won't change the scale of the data, just the size of the picture.

What you're probably comparing is your chart plotter settings. These have nothing to do with Navionics or CMAP, so it's unsurprising they look the same!

 

[lustyd]

Here is the same area on Navionics with their default settings in the webapp.

 

[dunedin]

After the Vestas accident Navionics stated they included those shoals even at little scales; they forgot a few other bits and pieces though
This is navionics for the central Atlantic, CMAP -at least "that" cmap- is identically blank, of course they are non commercial editions.

View attachment 128417

This is a raster NGA chart, tiny rocks/islands are shown, as well as sea mounts, the continental shelf, etc etc

Anybody using a chart view of that scale (ie large chunks of Africa, the entire width of the Atlantic and chunks of South America on the same page) for actual on board navigation to avoid hazards / islands would deserve anything they got. Would be better using a child’s inflatable globe.
So not a very relevant example to use

 

[requiem]

If you're comparing Navionics and CMAP that means you are not using their choice of detail. It's the chart reader/renderer which chooses what to show at a zoom level with vector charts, not the chart producer.

I can't speak to how those vendors implement their charts, but it seems somewhat dangerous to simply provide "all the detail" and abdicate the decision-making to the whims of whichever software was used to display it. Just as raster charts are drawn to a scale, standard ENCs have a compilation scale and based on that scale the cartographer makes such decisions as what features to include or exclude, and whether to describe a feature as a point or an area. For example, here's a comparison of two different ENC scales depicting Motuihe Channel in Hauraki Gulf:



Those objects are tagged with a minimum scale attribute, and the display software has the option to use that as a guide for de-cluttering. For example, the green buoy has it set to 59999, meaning that if you enabled such options it might no longer display once you zoom out to 1:60k.

 

[Roberto]

Can you show that chart on a 7" plotter? Maybe you're lucky enough to have a megascreen like ships?

Here is the same area on Navionics with their default settings in the webapp.