The Open-Ended World of Computerized Charting

By Daniel Piltch, Marine Computer Systems
(as originally published in Cruising World March 2002 Issue) 
  See Also:

Electronic Charting Software Comparison Chart

Connecting Your GPS to Your Computer
 
Though Bangor, Maine doesn't typically come to mind as the epicenter of electronic charting, it plays a significant role in the history of an industry that's less than 20 years old. It all started when the National Oceanic and Atmospheric Administration (NOAA) began experimenting with electronic versions of their paper charts in the 1980s. As interest grew in these computer based charts, they decided to partner with a private company in order to better distribute and support the new products. They solicited proposals from 37 companies for a special Cooperative Research and Development Agreement (CRADA). The winner was Bangor-based BSB Electronic Charts, a partnership of Blue Marble Geographics, James Sewall Company, the Better Boating Association - best known for their spiral bound ChartKit books of paper charts. Over the ensuing years, BSB was acquired by Maptech - creator of the first PC-based charting system - which still continues to publish electronic charts under the auspices of it's ongoing CRADA with NOAA.

Meanwhile, back in Bangor, Maine a boater-turned-computer programmer had the modest idea of creating a computer program that would help a celestial mariner calculate and display his lines of position to determine where in the world he was. As he continued to develop his program, Dennis Mills, an ex-journalist, received lots of feedback and suggestions. One of the important features he added based on these suggestions was the ability to plot a vessel's position directly on the new electronic charts being made available by NOAA. This program was eventually developed into the world's first commercially available Windows-based electronic charting system, the Computerized American Practical Navigator (The CAPN). Now at the helm of Nautical Technologies, Mills is still regularly adding features to his program.
.
Since 1991, many more systems have become available, and many vessels have outfitted their navstations with these computerized charting systems. Today, they're found on every type of boat from a 15' kayak to a 505' Destroyer. While they're increasingly popular, they're not right for everybody. There are three big questions that need to be answered when considering a new electronic charting system for a vessel:

1) Whether or not to get an electronic charting system.
2) Which chart display software to get.
3) Which type of charts should be used.

Making the Decision

Dealing with these in order, we come to the question of whether or not to put an ECS onboard. There are many benefits to having an ECS available onboard. By showing the vessel's position right on a chart, there's much less room for error in knowing where you are. As long as you can read a chart, you'll know exactly where your boat is. Route calculations also become much simpler. Answers to the age-old questions, "Are we there yet? How much longer?" are only a mouse click away. Tides and currents can be displayed right on the chart in the appropriate positions. No need to ask which tide station is closer. By using photographic charts, it becomes easy to differentiate strange landmasses in foreign waters. Keep an instant log of where and when you've traveled without ever having to pick up a pen. The features go on and on. However, most people tend to use ECS for the basic functions of position display and route planning.

Laying down a route or a collection of successive waypoints is as simple as pointing to a location on the chart displayed on the screen and just clicking the mouse. With each click, another waypoint is added to the list. Each list of waypoints is stored as an individual route which is saved in a library of available routes. Many sailors will have a dozen or more standard routes that they'll have on hand - say the quick evening around the harbor route, the pleasant overnight route, and the long 3-day weekend route. Long distance cruisers are typically less concerned about saving old routes and are focused more on the next leg.

For each route, and for each leg within the route, information is available on range and bearing to each waypoint as well as estimated time en route based either on actual boat speed or on a targeted average boat speed. Some of the more advanced packages will try to automatically take into account set and drift due to local currents, though this is generally awkward at best. Fuel consumption can also be estimated by some packages.

One of the most compelling anecdotes in favor of getting an ECS onboard involves a boat on a coastal passage encountering stormy weather. The tough decision of whether or not to pack it in and head for the nearest harbor is often overshadowed by the decision of figuring out what the nearest harbor is. Complex entrance channels, significant tidal ranges, strong currents, and wind conditions might make finding the nearest harbor more than just a trivial task. While the prudent seaman will have already marked routes to several "bail-out" harbors along the route on his paper chart, I know of few sailors that practice this wise but somewhat time consuming procedure. With an ECS, a few mouse clicks on various harbors can yield a very quick answer to the question, "how quickly can we be tied up and in a warm shower?"

Once the decision has been made to have an ECS onboard, the next logical question typically involves the choice of computer to bring and exactly where to mount it in an already crowded nav station. There are many, many options of which computer is most appropriate for use onboard - and almost as many opinions on how to select one. Without getting too in depth into a complex issue, two rules of thumb generally apply - (1) you get what you pay for - cheaper computers are generally cheaply made with cheaper parts, and (2) there's usually a reason that popular brands are popular - ask around to see what people are happy with. We maintain a useful set of information about purchasing onboard computers at www.MarineComputer.com.

An important factor to consider when making the decision to use an ECS is that it provides a great deal of efficiency and convenience, but it is a fallible system and it is based on more complex and sensitive technology than nearly any other system you're likely to have onboard. Supporters of Murphy's Law will contend that the system is likely to breakdown at the worst possible moment. Even optimists should concede that a backup navigation system is absolutely mandatory. For most mariners, this means carrying adequate paper charts for every area you intend to sail - and even those you might have to divert to. Another requirement is to know how to use these "old-fashioned" paper charts - simply having them onboard is not enough. Celestial navigation may be in its waning days, but plotting skills with pencil and chart are likely to be around for a long while. Likewise, the old salts that assume plotting a route on a screen is just the same as plotting it on paper should note how easy it is to connect two waypoints that send the vessel right over a rock or even a piece of land. A handy tip is to keep a pad next to the computer and regularly write down (or print out) your latitude and longitude along with the time. This will provide you some history for dead reckoning in the event of a technology failure. Different skills are required for electronic charting and for paper plotting - don't dismiss either set of skills.

Choosing the Right Software

So, we've decided to get an ECS. Now we're on to the second of the three big questions. Which charting software to buy? There has been some consolidation in the market in the last few years along with a few mergers and acquisitions. Of the survivors, the two most popular charting programs are The Capn by Nautical Technologies, and Visual Navigation Suite by Nobeltec. These two packages comprise the vast majority of all charting software used today. Other options available are: Offshore Navigator by Maptech, MaxSea by Informatique & Mer (distributed by NetSea in the US), ChartView from Weems & Plath (formerly from Nautical Software), and RayTech Navigator from Raymarine. Each of these has its unique strengths in certain areas. Notably RayTech Navigator & MaxSea offer excellent weather routing functions, while Nobeltec offers a radar overlay option.

The list of features available with each package grows longer each year and with each new release. Generally each release leapfrogs the competition. If one company includes a new feature (say the inclusion of photo charts), another company will include the same feature and another one (the inclusion of photo and 3D charts). Watching the industry is a little like watching a game of poker: "I'll see your new feature and raise you with two new ones."

Rather than buy the software with the longest checklist of available features, think hard about which features will be important to you. Ask others what features they've found most useful. Also pay very close attention to how easy or difficult it is to learn and use the software. Most companies will allow you to download and use their software for 30 days on a trial basis. Take advantage of this and try different programs. There is a definitive and distinct difference between the interfaces available, and there's not a single answer for choosing one that is the most usable for everybody. Depending on your background, you'll likely find one easier than another. While Nobeltec's software is most similar to other Windows applications that you might already be familiar with, The Capn is often praised by traditional navigators who are new to computers. The other packages also have their niches. Keep in mind that it takes a significant investment of time in order to become completely comfortable with a system. Your local salesman or dealer will likely only have invested the time in learning one package, and that will be the one he's most comfortable with and will try to push. If you're lucky enough to find someone who has equal expertise in several packages you might hear some very useful advice, but more often than not you'll have to try out a couple of different packages and decide on your own which you prefer.

Digital Charts

The types of digital charts available to the recreational boater has increased dramatically. Five years ago, the only option was to use raster charts. Today, there are raster charts, vector charts, photo charts, three dimensional charts, flat bathymetric charts, and even topographic maps of the coastline and street atlases built into some marine charting software. While Maptech has traditionally dominated the market of providing digital charts on CD, others have recently been challenging them. Nobeltec's Passport series of vector charts debuted in 1999 and have become very popular. Softchart International created a series of raster charts to compete with Maptech's NOAA-sanctioned charts. Some of these digital charting companies have familiar names as they're also in the charting software business. This tends to lead to much confusion. For example, it's possible to use Nobeltec's charting software with Maptech's charts, but not Maptech's software with Nobeltec's charts.

Raster charts are exact copies of paper charts. Think of someone taking a photograph of a nautical chart, and making that photograph available on screen. Every item that shows up on the paper chart is replicated on the computer. This is convenient for using local knowledge as expressed in some cruising guides as "anchor just south of the letter 'Q' in the printed words 'Quahog Cove' on chart 12737." The 'Q' on the computer screen will be in exactly the same place as the 'Q' on the paper chart.

Vector charts, on the other hand, are made by creating a list of data that is then "drawn" by the computer each time a chart is displayed. The list might contain items such as a depth sounding of 27 feet at precisely 43° 39.802' N, 70° 02.442' W and a red bell buoy marked "2Q" at precisely 43° 40.627' N, 69° 59.886' W and so on with many, many more items. Each time a chart of the area is displayed, the computer runs through its long list of items and displays each one on the screen in the appropriate position.

The ability of the computer to re-draw the chart each time allows for the use of layers of information. You might choose to show the depth soundings, and the ports & facilities but not the contour lines. It's also easy to change the attributes of certain items - showing all depths shallower than 10 feet in bright red and all depths greater than 100 feet in a light (unobstrusive) shade of grey, or showing how far and wide the light from a lighthouse will reach.

Oddly enough, it's far easier for computers to work with vector charts rather than raster charts. Vector charts tend to take up less room, offer more customizable features, and can be displayed more quickly than their raster equivalents. One single CD might contain enough raster charts to navigate from the Canadian border on the East Coast down to Rhode Island. With vector data, one single CD contains enough vector charts to circumnavigate the planet!

There's no question that vector charts are more flexible, but despite the tremendous amount of research and effort being done, they're still a relative newcomer to the world of CD based digital charts. Most charting software has (or soon will have) the ability to work with both types of charts: raster and vector.

Other chart types of note are photographic charts and 3D charts. On a photographic chart, your vessel is shown in place directly on an aerial photograph of the harbor or coast you're sailing. I sometimes get asked if photo charts are available for offshore waters. As always, I politely explain that it's really not necessary to have a photographic chart if there are no land features in the photograph. Another common misunderstanding comes from the fact that when the aerial photos were taken, there may have been boats on the water at the time the photo was taken. These boats were then captured on film and later wound up being shown as part of the photographic chart. Some boaters will look at the photo chart being displayed on the screen and wonder why they can't see the tanker which shows up so clearly on the photo but doesn't seem to be anywhere in sight in real life.

3D charts show a contoured relief of the seafloor. Canyons, seamounts, and channels are clearly visible. While some dismiss these charts as an eye-catching novelty for vendors to show off at boat shows, others maintain that this type of view of the seafloor is invaluable when selecting a spot to anchor or for finding fishing holes.

No matter which chart type or combination of types you choose, you'll soon be faced with the prospect of updating these charts. All of the software programs will allow you to manually annotate a chart and add your own symbols and text. This could include marking a favorite gunkhole for anchoring or marking a buoy that has changed. Nobeltec releases new charts about 4 times each year, while Maptech has a weekly chart update subscription service. While you'll need Maptech's Offshore Navigator software if you want to be able to roll back the updates and see how the chart looked in a prior week, the up-to-date charts will work with any charting software. Unfortunately, keeping regularly updated charts on hand is a burden in both the world of paper charts as well as that of digital charts. Buying chart updates for your digital charts takes far less time than updating the paper versions by hand, but it's also more expensive.

The Latest and Greatest - Free Charts and Other Goodies

The original raster charts available from Maptech via a research agreement with NOAA were known simply as Raster Nautical Charts (or RNCs). These charts are still available today under Maptech's trade name "Digital ChartKit" and are widely used. NOAA has been working diligently on a new suite of vector charts that comply with the International Hydrographic Office (IHO) standard called S-57. This standard applies to commercial vessels wishing to use electronic charts for navigation and includes very detailed information on what information must be included on the chart. These S-57 compliant charts are known as Electronic Nautical Charts (ENCs). NOAA is well on the way to producing their entire catalog in this new ENC format, and their charts are available for free on the Internet at http://chartmaker.ncd.noaa.gov/mcd/enc/download.htm. These charts are typically used with high-end charting software known as Electronic Chart and Information Display Systems (ECDIS). These systems are approved for commercial use by a variety of organizations including the Radio Technical Commission for Maritime Services (RTCM), the IHO, the International Maritime Organization (IMO), and the International Electrotechnical Commission (IEC).

As this progress on these ENC and S-57 charts continues at NOAA in Silver Spring, Maryland, down the road in Bethesda, Maryland, the National Imagery and Mapping Agency (NIMA) is hard at work developing a somewhat different and incompatible type of vector chart known as a digital nautical chart (DNC). These charts are intended primarily for Navy and Coast Guard use and aren't generally available to the public.

Chart Type Acronym Usage

NOAA & Maptech's raster charts RNC (Raster Nautical Charts) Widely used - recreational & commercial
NOAA's S-57 vector charts ENC (Electronic Nautical Charts) Commercial ECDIS systems
NIMA's vector charts DNC (Digital Nautical Charts) Military & government use only

Other then these new chart types, there are several features emerging that fall generally under the category of integrating available information. For instance, Simrad now offers a high-end system that will transfer data from a fishfinder to a chartplotter and show schools of fish directly on a nautical chart. Nobeltec offers RadarPC which displays radar information from a Si-Tex or Simrad antenna directly on a PC screen, and optionally overlays this radar image onto a chart. Just about all of the systems mentioned above, with the exception of ChartView, offer integrated weather information to varying degrees. At the high end, RayTech Navigator's Sail Racer and MaxSea's Yachting package both offer suggestions for navigating through weather patterns while maximizing distance traveled. Nobeltec offers the ability to overlay daily downloaded or emailed weather information on a chart, and both the Capn and Offshore Navigator offer built-in tools to access live weather information from the web.

As the world of electronic engine monitoring matures, expect to see some crossover here as well. The Ship's Information Monitoring (SiMON) system from nView Corporation already adds GPS and instrument monitoring to its array of engine monitoring controls. It's not inconceivable to expect engine monitoring, weather routing and navigation software to be combined to offer a suggested route minimizing exposure to severe weather, while maximizing fuel efficiency. In fact these systems are already available to commercial shipping interests.

A Good Idea Getting Better All the Time

Electronic charting has come a long way in the last ten years. Since its modest beginning helping celestial navigators with their calculations, the list of available capabilities has grown tremendously with some very useful features (seamless charting) and some questionable ones (being able to change a buoy symbol into a beer can). As more onboard information is available digitally, expect to see more integration of all of this information onto a single computer screen. If radar, weather, and position information are all currently available on today's systems, imagine what will be possible with tomorrow's software.

 

See Also:

Electronic Charting Software Comparison Chart

Connecting Your GPS to Your Computer

 Return To Top of Page   Return To List of Articles