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Electronic Charting (long)

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lcharlot
Master Marine Consultant

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Antigua and Barbuda
1301 Posts

Initially Posted - 09/17/2006 : 21:59:09

ELECTRONIC CHARTING, IT'S HERE, IT'S EASY TO USE, AND IT'S PRACTICALLY FREE

Thanks to Duane Wolff, our Association Chief Measurer, I have put together a really nice electronic charting/mapping application, and an updated collection of NOAA Navigation charts. NOAA has committed to supporting an all-electronic Marine Navigation System. You can still buy the old fashioned paper charts, but NOAA has now made available, <i>free of charge</i>, all electronic navigation charts for US waters, These electronic charts come in two forms: BSB/KAP and S-57 ENC.

BSB/KAP's are raster scans of the traditional paper navigation charts, each Geo-referenced to an appropriate Datum (like NAD 83 or WGS 84), so that when you load one onto a digital chart software application, the cursor or boat movement displays the actual Latitude and Longitude on the screen. BSB/KAP's look just like the paper chart, except that the colors may be a little different. S-57 ENC's are vector instead of raster, and each is actually a mini GIS database, containing not only shore outlines, navaids, and navigation hazards, but also depth soundings and textual data for many of the objects (like buoys) embedded in the chart file.

The charting software I have is called "SeaClear II"; it is a freeware application you can download from the 'Net. It uses raster charts in BSB/KAP or WCI format, but not S-57 ENC's. I have another software app called NavPak Pro that reads BSB/KAP and S-57 ENC, but it's a demo that's not fully functional (NavPak will not connect to a GPS until a registration key is entered; this software costs $149 I think). If your computer, running SeaClear, is linked to a GPS, a boat symbol is displayed on the map, along with real-time speed, heading, route and waypoint info, and other data. As the real boat moves, the boat symbol on the screen moves, and as it reaches the boundary of the currently loaded chart, the adjacent chart of the largest scale will be loaded automatically. The software can also be used to plan and plot routes and waypoints, then these can be uploaded to the GPS. Or Waypoints, Tracks, and Routes gathered live on the GPS can be later downloaded and plotted on SeaClear. There is also a "dead reckoning" mode, for use without an active GPS; in DR mode, a speed, position, and heading are entered, and the boat symbol is moved along the chart with manual steering and speed commands. This can be used like a simulator at home when you are not on the boat but want to "play around" with your charts.

Before we left for our Alaska cruise on the MS Statendam last month, I downloaded NOAA BSB/KAP's for most of the West Coast, including the San Francisco Bay and Delta, Lake Tahoe, the San Juan Islands, Hawaii, and all of Alaska. I loaded everything onto my laptop, and on the second night of our cruise, as we were approaching Ketchikan, I went up on deck and tried it out for the first time. I set up the laptop on a patio table, plugged in the GPS (I have a Garmin E-Trex; small, inexpensive, and it came with a PC interface cable), and powered up. After starting SeaClear and telling it to "listen" for the GPS on Com Port 2, there was a slight delay, maybe 15 seconds while the software synchronized itself to the GPS and searched the chart database, then behold! The proper chart, "#17428 Revillagigedo Channel, Nichols Passage, and Tongass Narrows",loaded up and there was the boat symbol right where it should be, slowly ticking along at 18 knots, with the current Lat-Long and Heading data! Over the remaining 11 nights we were on the cruise ship, I tried to go out on deck with the laptop and GPS every evening that the ship was underway, and track our movement for a half-hour or so. I have all the stored tracks, and could show you, at least for short distances, where we were. I also carried the GPS on most of our shore excursions, and except for places where we were indoors, I have stored tracks for the walking tours we did, and for the Whale Watch tour we went on in Juneau. This one is really cool, as I can tell from the track the exact places where the boat stopped for the one Orca and several Humpback whales we saw, plus the Sea Lion rookery on Little island.

On the return drive home from Vancouver BC to Sacramento, I left the GPS running on the car's dashboard, and later downloaded the track to SeaClear for more than 300 miles of that drive. One last item about this to take note of: the Sea Clear software is not in any way restricted to "official" marine navigation charts. It will work with ANY raster scanned map that can be georeferenced to Latitude, Longitude, and a recognized geodetic datum like NAD 83 or WGS 84. These maps include USGS Quad Sheets, many kinds of road maps, and even ortho rectified aerial photos. For example, you could download a series of strip images of an area from Google Earth, taken at a suitable altitude (1500'~4000' is typical, depending on the resolution of the photography), stitch the strips together with Photoshop into a unified BMP image file, then note the Latitude and Longitude of certain key features by referencing back to Google Earth (or checking them yourself in the field with a handheld GPS). Once you have the LatLong data for at least 4 points on the image, it can be Georeferenced in SeaClear and then used just as well as any commercial map. I am in process of doing just this for Folsom Lake, which has no good navigation charts available. There are USGS quad sheets of the area, but unfortunately, Folsom Lake is split right down the middle by a map boundary, and the two adjacent quad sheets don't match very precisely; both the registration of the line work and the coloration are somewhat different between the two sides.

The system requirements are fairly easy: Any PC or laptop manufactured in the last five or six years would be fine. Windows 2000 or XP is recommended, but older PC's running Windows 98 should still work. For "real time" use, your GPS must be capable of sending NMEA data over an RS 232 or USB cable, and your laptop must have a compatible RS 232 or USB port. If you have a newer laptop, and an older GPS, you will probably encounter the same situation I did: The GPS output is RS 232, but the laptop has only a USB connection. Not to worry, there are adapter cables for $15 for just this situation. I had to use one of these adapters and it works fine.

HARDWARE COST: (assuming you already have a computer). I paid $110 for a Garmin E-trex Legend, which included an RS 232 PC interface cable. The E-trex is a small handheld GPS about the size of a cell phone. It easily fits in a shirt pocket. I also had to buy a $15 USB/RS 232 adapter to connect the GPS to my laptop.
SOFTWARE COST: Zero. The SeaClear software is free, and all NOAA electronic charts are now free. Software and charts can be downloaded from the internet, but a broadband connection is recommended. You don't want to try to download 1500 megabytes of charts on dial-up. Caveat: So far, only the navigation charts of USA waters are free to download from NOAA. Unfortunately, the Canadian charts for British Columbia are not only not free, but are quite expensive, at least from the point of view of a recreational boater: $349 for each chart package. Package #1 covers the Inside Passage from the Strait of Juan de Fuca to the northern tip of Vancouver Island, which includes the San Juan and Gulf Islands and Desolation Sound. Package #2 covers Queen Charlotte Sound and Hecate Strait to Dixon Entrance (where SE Alaska begins), and Package #3 covers the west side of Vancouver Island and the Queen Charlotte Islands. I have not been able to locate a source for purchasing electronic charts of just the Gulf Islands, which is where most of our C-22 Fleet 4 members go. It looks like they only offer the three packages, and to get the Gulf Islands, you have to pay the full $349 for all of the hundreds of charts covering the entire eastern side of Vancouver Island.

WEB LINKS: Download the SeaClear software at: www.sping.com/seaclear/
Download NOAA BSB/KAP raster charts at: www.nauticalcharts.noaa.gov/mcd/raster/download.htm

Someday, if I make it retirement still intact and reasonably healthy, I hope to spend a whole summer cruising my boat up the Inside Passage from Bellingham, WA to Port Hardy, BC. Full covereage of this region at 1:40,000 or larger requires at least several hundred charts I think, way more than would be practical to carry in paper form on a Catalina 25, so having them in electronic form on the computer would be great.

Hope some of you will find this info useful. Fair winds!

Fair winds!

Larry Charlot
Catalina 25WK/TR Mk. IV #5857 "Quiet Time"
Folsom Lake, CA

"You might get there faster in a powerboat, but in a sailboat, you're already there"

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Notice: The advice given on this site is based upon individual or quoted experience, yours may differ.
The Officers, Staff and members of this site only provide information based upon the concept that anyone utilizing this information does so at their own risk and holds harmless all contributors to this site.