Tuesday, December 15, 2009

Navigation Software

I've been in Charleston long enough. After you soak up so much history, eat so many shrimp and grits meals, walk so many miles looking at truly magnificent homes, you're bound to take a day or three to explore some software. Ok, maybe not all of you.

So here's the thing: free navigation software. Now, NOAA has been supplying charts in digital formats for a few years now. Like books, there's nothing like a paper chart to keep track of where you are in the world (I can't translate lat and long numbers to a physical position in my head without a chart. I suspect most people can't).

Of course, chartplotters exist on many boats. I have two - a Raymarine C80 and a Raytheon Pathfinder as a backup. I'm very happy with both systems, but what about someone who doesn't have unlimited funds to acquire this stuff? What do they do? Well, here's the answer and it's way less expensive than you can imagine.

Maptech supplies charting software with its chart kits. It's copy protected, difficult to use, and requires, at this time, finding and installing an update to use Garmin hand-held GPSs. Because it's a 'lite' version of their charting software, there's a bunch it doesn't do. Moreover, it can only be used on one computer - if you need to move it to a different one, you have to convince Maptech that it's a legal move. Those 'features' are the kind that killed Lotus 123 and dBase as premier software packages in the '80s. Apparently big companies don't learn all that well.

That said, there are two programs that I know of that are free and use the free downloadable charts from NOAA.

Before I go there, though, there are two types of charts NOAA supplies called Raster Navigational Charts (RNC) and Electronic Navigational Charts (ENC). RNCs are a digital picture of the real paper charts. If you could print them out on a large size printer you would have essentially what you purchase in a store as paper charts - in fact, a company (Bellingham Chart Printers) exists that prints these files in grey scale for a fraction of the price of new colored charts. I know of world cruisers that have used them quite happily.

ENCs are data rich vector charts - they contain, essentially, a database of objects with attributes. If you query a mark, you'll receive the information about it such as name, color, purpose, height and other things. The charts themselves are visualized somewhat strangely to people used to using paper charts because they're line drawn. There's no shading. It's like looking at an architectural drawing, except with buoys.

Most chart plotters actually use both chart sets - the visualization is with the raster chart so it looks familiar, but when you click on something for information, it querys the underlying vector chart based on your cursor position and you get the presentation of the information.

Don't worry if this is getting too technical - if you're familiar with the transparencies of the human body in an encyclopedia (most have them) then you can picture how this works. If not, just take my word for it.

Now for the programs. The two I'll discuss are SeaClear II and OpenCPN. Although both are capable chart plotters and navigation aids, OpenCPN offers the ability to control the autopilot and set and save routes to follow. Both integrate easily with GPS units, with SeaClear II able to connect to Garmin units using the USB without modification. The OpenCPN uses NMEA 0183 exclusively.

Sea Clear II uses the RNCs and is very easy to use - it is not designed to be a full fledged navigation system, in my opinion. But it is very easy to use and very useful as a chart plotter. It allows you to make routes and save waypoints. I've used it for couple of years and it's great for deciding overall trip strategy. I like it alot.

I've recently been turned on to OpenCPN. I'm a big fan of open source software and I use Open Office instead of paying Microsoft huge sums of cash for a questionably useful product. But I digress. OpenCPN was written specifically to do all the things a chart plotter does - run autopilots, set and follow routes, provide information about navigational items and much more. As you move from place to place the program automatically loads the chart for that area at the closest scale it can find for where you currently on. Sometimes, that takes a few seconds, but I suspect that has more to do with my computer than anything else.

OpenCPN uses both RNCs and ENCs as I've explained above. There's a huge implication to this fact - first, all the charts that NOAA provides are free to download, and second, if you have a PC with a decent monitor and three USB or serial ports and a GPS unit you can have a full fledged navigation system/chart plotter. It will run any NMEA 0183 autopilot (like, for instance, Raymarine). It will use any NMEA GPS antenna (like, for instance Raymarine or Garmin). And it will run on Windows and Linux (and maybe Mac but I won't vouch for that). It accepts AIS input and displays it. It is very powerful.

So, if you wanted a system you could purchase a decent laptop for $500 or so, load it with Ubuntu (free linux), install the OpenCPN, connect your autopilot, your GPS antenna ($250), your AIS receiver (optional, but fun $500) and you'd have the equivalent of a $3000-$6000 system. Moreover, with a little ingenuity, you could add a display at your helm with a touch screen. To be perfectly honest, I'm tempted to try this myself...

Anyway, there you have it - free navigation software. If you've got the time and a PC, I'd sure enough have a look at both. The charts are free from NOAA - RNCs and ENCs. I find downloading them by Coast Guard Zone the easiest. Unzip to a directory you'll remember and point the program at it - then go to town (sea)!

That's it for now. I'm leaving Charleston to spend Christmas with friends in Brunswick GA.

See you on the water!


Patrick said...

Great post Bob!

ScarlettJacob said...

Navigation Systems have revolutionized how we travel. Once upon a time it was necessary to use a folded up map to know where to go but these days all you have to do is plug in your sat nav and tell it where you want to go.Global Navigation Satellite Systems (GNSS) is the standard generic term for satellite navigation systems that provide autonomous geo-spatial positioning with global coverage.Mio Navman M300

Dave said...

It's always a good idea to have a backup Bob. NOAA now posts charts arranged in a booklet format that you can print at home for free to meet that purpose. See NOAA's web site at http://www.nauticalcharts.noaa.gov/staff/BookletChart.html.

The BookletCharts are even being updated by NOAA though not on a weekly basis yet like the RNCs, ENCs and On-Line Chart Viewer are.

Cap't Bob said...

I would *never* suggest that anyone go to sea without paper charts and at least a basic facility with using them. To depend soley on electronics is to invite a subtle grounding as a minimum and a disaster at worst. In addition to four layers of GPS, two of autopilot, I have all the charts, chart kits, and a more than rudimentary knowledge of their use. My motto is that systems should degrade gracefully - without anything but the rig and hull I should be able to get home...

Guru Marine said...

I'd love to see to see OpenCPN running on my MacBook to avoid having to book into XP for Chart Navigator Pro. Good looking program.

drware said...

Thank you for the information in this post. It is a good starting point to understand NOAA charts and how they work with open source software.

John said...

Hi Bob,

Thanks for the info. I'll have to check this out.

S/V Sailor Dance
1990 Caliber 33
Long Island Sound

Cap't Bob said...

First, Dave, I'm going to look into that - I don't yet have a printer on board, but I should soon.

Guru - I'd be very surprised if you couldn't run it in an X-Windows terminal mode or whatever Mac uses for graphic access to the Unix OS. If I had a Mac, I'd sure try it! If you do, and you get it to work, I'd be tickled to let others know how you did it.

John, you're welcome - up until October 2009 I was sailing the Long Island Sound and its environs. It's still one of the best cruising places in the world!

John said...

I tried SeaClear and OpenCPN. Unfortunately I have to give both the THUMBS DOWN. Neither program worked correctly. SeaClear I couldn't get it it to find any of my downloaded RNC's. Documentation was not much help.

OpenCPN displayed my downloaded ENC's but would not display the water depth. Documentation was non-existent. I'm a big fan of open source but both these applications leave much to be desired.

S/V Sailor Dance

Cap't Bob said...

Hey John,

The biggest problem I've found with the two programs is documentation - in both cases a little manual would help.

You can download a manual for SeaClear II - I have one on my desktop. Finding the charts requires using the MapCal program.

For OpenCPN, finding out info is harder - Use the Tools icon on the menu to change what's visible on the ENCs. Also, if you're doing routes, enable the GPX icons on the etc. tab.

Admittedly, having written software and trained people for 26 years helps me figure this stuff out.

dan said...

There is a new compiled version of openCPN out for the OS X platform. Seems to work fine. I also have the GPSNavX software where I have thousands of waypoints stored and a few dozen routes. I use a Bluetooth BT338 GPS from GlobalSat with a MacBookPro running on SnowLeopard.

The only problem is reading the Info database when you right-click on a map object. A empty screen comes up every time for any type of object.

I have exported the routes in .gpx format from GPSNavX and reimported them in openCPN on a CM93(may 2009 ed.) chart and they match perfectly.

I still have to test the system "en route" to see how precise the GPS will navigate in openCPN.

Daniel,Farnham, QC. Canada

software testing consulting said...

SeaClear seems to do the best work. I can't agree less, it seems to have a user friendly interface which makes it very easy to navigate, and very easy to use.

Christopher Telles said...

I'm obviously a little late to this eCharts discussion, but a little better late than never so I've heard.

"connect your autopilot, your GPS antenna ($250), your AIS receiver "

I expect to do all of the above. I found and downloaded OpenCPN before stumbling onto your blog. I do have one question as a non techie type. Assuming you wanted to have a stationary laptop at the Nav Station, how and or what would you incorporate into the system so a portable display e.g. Surface or iPad could be used out in the cockpit?

Interesting stuff here. Thanks for the valuable input!

Cap't Bob said...

Hi Chris,

The only way I can think of this is to have a wireless network on the boat. Then you'd use the surface with a remote terminal program at the cockpit to operate the main PC at the nav station.

I'm sure there are other ways to do it - but it's very close to the way the new Raymarine MFDs are controlled by Android or Apple tablets.

There are free, open source remote terminal programs, RealVLC being one of them I've used. Once set up, I'd think you'd be good to go no matter where you are on the vessel. Here's an article on them: http://www.junauza.com/2011/02/linux-remote-desktop-software.html

Especially useful if you're using Linux. TightVNC also has an Android client, so there's that.

Good luck! Many of the parts I spoke of when I wrote the entry are far cheaper and better than they were then!