dgadee
Well-Known Member
Perhaps I caused the confusion. They are not available for OpenCPN.
Raspberry Pi, worth a dabble?
- Thread starter James W
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GHA
Well-Known Member
So it's not the charts but you prefer raster to vector? Vector charts don't seem to differ much , and opencpn lets you customize the viewing options quite a lot. O charts are all Hydrographical Offices data.
JumbleDuck
Well-Known Member
As I recall, VMH charts are encrypted and the images decrypted square by square when needed for display. The decryption is done by a windows-only blob (programme) which comes with the charts.
JumbleDuck
Well-Known Member
Raspberry Pis are reasonable furn for playing with, full of frustration. My crew has turned one into a car satnav using OpenStreetmap, some software I don't know, a GPS puck and a 7" touch screen. It works quite well ... but it cost about the same a reasonable tablet. Move up to 10" screen and it's a lot more than a tablet, and still needs an external power supply, which it hammers.
If you just want to play with Linux, I'd recommend buying a secondhand desktop machine on eBay (£50 will get a good one) and using that, or install VirtualBox and play on a virtual machine. The number of real life applications for which a Raspberry Pi is a cost-effective and technically adequate solution is not zero, but it is pretty small.
laika
Well-Known Member
I think you'd need to qualify that by modifying "real life" to "consumer-grade". There's huge numbers of startups, especially in the IOT space, using these things in commercial products. "Educational tool" might be classed as one application but it's a *really* big one. A quick google shows 30 million of the things sold as of the end of last year. I wonder how many people have one on board worldwide...I'm guessing 10s of thousands but don't know. It's not confined to yachts: I've had mails from multiple people using them on research vessels.
The value of a pi (and similar) is not as a tool for learning Linux but as something to explore the possibilities of hooking up a computer to the real world. The real life application at which it excels is facilitating dabbling
dgadee
Well-Known Member
Yes, but I haven't actually put the o charts on yet. My anti-vector feeling is from Navionics on a tablet (particularly after VMH ran out while going east at the Balearics). What I don't like is having to scroll in and out for detail (making sure you are not hitting a rock on a course which seems clear, for example). Raster charts have all the information in a much more coherent visual system. Even finding harbours you need to scroll in and then having found it, you scroll out and it disappears again. Edward Tufte stuff.
JumbleDuck
Well-Known Member
Yes, good point.
The value of a pi (and similar) is not as a tool for learning Linux but as something to explore the possibilities of hooking up a computer to the real world. The real life application at which it excels is facilitating dabbling
I would be interested to know how many home Pis are actually hooked up to stuff compared to Arduinos. We've been looking at various Pi hats for this sort of thing and the reviews are uniformly off-putting. Might still be tempted by a Moitessier hat although a nice Garmin handheld GPS is cheaper.
GHA
Well-Known Member
Think it's largely what you're used to, years on cad and computers in general I can't get on with raster at all. seems pointless on a computer. Opencpn has options to alter how much detail you have at different zoom levels. Though satellite images are gold dust
GHA
Well-Known Member
Pi/openplotter/signalk on a boat is a match made in computer heavenThe value of a pi (and similar) is not as a tool for learning Linux but as something to explore the possibilities of hooking up a computer to the real world. The real life application at which it excels is facilitating dabbling
So much capability easy to set up drawing so little current. Can't think of any other system which offers so much even at many times the cost. PCs/Macs don't have the GPIO capabilities to easily connect sensors.mbroom
Well-Known Member
VMH charts also work on Android, via Marine Navigator app. I am not a computer whizz, but I think Android runs on a Linux kernel.......
AntarcticPilot
Well-Known Member
Just to reiterate what I've said many times - all modern charts are produced in vector form, and primarily marketed as such for use in Ship navigation systems (which have to have certification etc. before they can be installed). Raster products are a secondary product these days, as are printed charts (though charts are still produced as sheet based products, for reasons to do with international agreements). Raster products are FAR less flexible than vector ones, as you are restricted to what can be shown on a display, with NO ancillary information available, such as (for example) contact information for harbours or marinas at the click of a mouse. Further, raster displays have failure modes that are not apparent, and can result in narrow lines disappearing or changing their ornamentation if zoomed out. To illustrate, imagine what happens when a line intended to be 1 pixel wide is zoomed out so that 2 pixels are reduced to 1. Exactly what happens depends on decisions made by the maker of the display system, but whatever choices they make, it won't be what you expect! Possibilities include the colour values of the two pixels being averaged, one pixel "winning" over the other (but according to what rules?), and no doubt others I haven't thought of! Vector displays avoid all such problems, and most of the issues people report are essentially down to user error.Think it's largely what you're used to, years on cad and computers in general I can't get on with raster at all. seems pointless on a computer. Opencpn has options to alter how much detail you have at different zoom levels. Though satellite images are gold dust
Seriously, the raster/vector argument stopped being sensible in about the year 2000, and believe me, I was professionally involved with this during the period when it was a live discussion!
dgadee
Well-Known Member
Maybe for professional users, but old boys like me still like the look of print. As my bookshelves show.
JumbleDuck
Well-Known Member
... on ARM hardware. Yes, no reason why any encryption couldn't in theory be done under Linux but whether it actually can be is a decision for the UKHO. However, there is a Spanish company selling what I am assured are functional UKHO charts of OpenCPN under Linux, as long as you don't mind the worlds least penetrable terms and conditions and a website looking like something the Bulgarian mafia threw together in 2003.
AntarcticPilot
Well-Known Member
My point is that printed products are prepared using vectors, not raster. That you prefer the look of a printed product is fine (you should see my bookshelves; thousands of books!), but it's just as easily and more reliably attained by using vector products rather than raster. I think (but am not sure) that ship ECDIS systems have a standardized representation of charts that replicates the IHO standard (like Admiralty charts). It can be done; that it isn't is more to do with marketing decisions than anything else.
laika
Well-Known Member
Interesting question. No-one buys an Arduino *not* to hook up to stuff. Probably plenty of people actually do buy Pis to use for educational purposes which don't relate to physical interaction, ie because they want to learn programming, Linux or whatever when as you pointed out, there are easier/cheaper ways to achieve that. If people have a project in mind, their choice of Arduino vs Pi might not be based on best tool for the job, but most familiar tool. Are you saying that you're finding the quality of arduino shields tends to be higher than pi hats? I confess it's not something I've looked at and I'm not sufficiently confident in my basic electronics knowledge to make quality assessments anyway.
JumbleDuck
Well-Known Member
I've never used Arduino, though I know people who do. They may well have the same problems, but I am struck by how lukewarm at best reviews of Pi hats are. Perhaps just an inevitable consequence of an open market, but it makes me hesitate before buying anything.
dgadee
Well-Known Member
Is the Arduino not just a hardware controller - e.g. sensors? Can it run a navigational charting program?
laika
Well-Known Member
No, sorry, we're going off-topic a bit. An arduino is a little board based around a microcontroller as you say. It doesn't run a full operating system like a pi. For simple electronics control projects that's often the most efficient approach but it's not a thing for running a chartplotter program on. Like the pi there's a little ecosystem around arduinos. The convenient add-on boards you can buy for arduinos are referred to as "shields" whereas they call the stackable ones for the pi "HATs"
laika
Well-Known Member
Or maybe it's a problem with expectations? The pi is a cheap and cheerful educational tool. It's been appropriated by people saying Hey! I can use this instead of £3000 worth of navigation kit! or £1000 of AV kit. So they buy a £100 add-on board made by and for hobbyists and are disappointed that when combined with their £40 computer it's actually a bit rubbish compared with the expensive commercial products. IIRC GHA is pretty happy with his hi-fi add-on board. To go back to the OP, it's ideal for dabblers but be realistic that neither the pi nor the add-ons are necessarily going to be slick commercial-grade solutions. It does allow you to build stuff which you can't otherwise buy of course...
dgadee
Well-Known Member
Are we?