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Do-It-Yourself - August 2010
By Joel McNamara |
If you kayak on U.S. coastal waters, you already know that NOAA nautical charts aren’t cheap. The cost of official paper charts has crept up over the years to more than $20 apiece. That can put a good-sized dent in your wallet if you’re planning an extended trip—especially when you’re forced to buy charts that may cover only a small part of your intended route. And sticker shock isn’t the only gotcha. You also have to deal with extra large, super-size-me charts that were never intended for use on a kayak deck.
So what’s a frugal paddler who’s frustrated by playing chart origami to do? The good news is, thanks to our friends at the National Oceanic and Atmospheric Agency (NOAA), you can make your own inexpensive and kayak-friendly charts.
BookletCharts Briefing
The easiest way to make kayak-compliant charts is to download a NOAA BookletChart. These digital charts come as Adobe Acrobat PDF files. They contain all of the information a full-sized chart has, but have been reduced in scale and divided into a series of handy 8.5 × 11" pages just right for printing.
According to Ed Martin, Chief of the Office of Coast Survey’s Customer Affairs Branch, NOAA recognized that not every boater had a vessel with an enclosed cabin and a chart table. So in 2006, the agency started working on prototype, digital small charts suited for small craft. At first only parts of Chesapeake Bay were available, but following a wave of positive feedback the program expanded and now BookletChart versions of just about every NOAA chart are available to download.
Getting a BookletChart is a snap. Point your Web browser to: ocsdata.ncd.noaa.gov/BookletChart/ and download the chart you’re interested in. The PDF files range from 5 to 10 megabytes in size, depending on the chart. Once the file is on your hard drive, open it up with Adobe Acrobat Reader—just about every PC and Mac has this software, but if yours doesn’t you can get it for free from: www.adobe.com.
The first few pages of a BookletChart have information extracted from the Coast Pilot about the chart area, followed by some basic information about the chart itself. Next are the actual charts, conveniently formatted as 8.5 × 11" pages. You can print—in your choice of black and white or color—the entire booklet or just the pages you want. The tiling of the pages varies from chart to chart. There are some pages that may overlap all but an inch or so of one chart, others that just butt up against each other. You may find you don’t need to print all of the pages to get all of the coverage you need. The first page is a chart index that shows which area each page covers. The pages have a large number in the lower corner so if you only want to print selected pages it’s easy to specify them.
Once you’ve printed the charts, you can mark them up with a pencil or pen, plotting course lines, adding destination spots and including any trip-specific notes. I’ll often use a scanner hooked up to my PC to make a digital copy of a BookletChart I’ve edited by hand. You can skip the scanning if you have a graphics program that allows you to edit PDF files on your computer. These file copies are nice since you can keep them for future reference, email them to a friend as part of your float plan or send them to fellow paddlers who’ll be going with you on a group trip.
To ensure your homemade charts don’t turn into a pulpy, smeary mess while you’re on the water you have a number of options. Resealable plastic bags, laminating machines, clear contact paper, liquid sealers such as MapSeal, chart cases, or using special waterproof printer paper all do the trick. (See “Waterproof Paper for Kayaking” in the April 2008 issue of SK.)
NOAA has been test-piloting BookletCharts for a while, but thanks to getting some of the kinks worked out of the software used to create them and a large amount of positive public comment, the “experimental” status will be going away soon— probably by the time you read this. That means the charts will be updated with the latest information on a weekly basis, the same as with their full-size digital and print-on-demand charts. (Here’s a tip: The bottom of page 7 of a BookletChart lists when the chart you downloaded was last revised.)
Navigating NOAA RNCs
BookletCharts are based on the same data used to produce NOAA Raster Nautical Charts (RNCs). These are digital charts the government makes by scanning full-sized paper charts. RNCs are designed primarily for use by navigation software packages. A navigation program displays the charts, and thanks to an invisible layer of data embedded in the RNC can also determine the latitude and longitude of any point on the chart. Hook up a GPS receiver to a laptop, run the program and a chart appears on the screen with your current position. Move the cursor and the latitude and longitude under the cursor is shown.
Up until December 2005, you had to purchase these digital charts. They were cheaper than buying the corresponding paper versions but were far from inexpensive. Then, thanks to an
expiring licensing agreement, NOAA decided to begin offering RNCs on the Internet for free. You can go to www.nauticalcharts.noaa.gov and follow the instructions to download any of the latest updated U.S. charts. (NOAA also produces Electronic Navigation Charts (ENCs). These charts are vector data sets and are of limited use to the do-it-yourself chart maker.)
Since most kayakers don’t strap laptops to their decks, RNCs might not seem very useful. That’s not entirely true since you can use the digital charts with navigation software on land to plan trips on your PC as well as print out paper copies of the charts. While commercial navigation software can be costly, there are free (such as SeaClear II: www.sping.com/seaclear/) and other low-cost alternatives available. (See “Digital Navigation for Kayakers” in the February 2005 issue of SK for more on navigation software.)
Using RNCs with SeaClear II and other navigation programs is mostly a no-brainer, you just open the chart file with the program, it appears on the screen and then you can scroll around to view it. But I want to clue you in on a little-known way of turning RNCs into your own custom charts.
Checking Out Chart Reprojector
RNCs are based on a file format called BSB (the initials of three companies that partnered to make digital charts for NOAA back in 1994). Unfortunately, this file type can’t be opened by Paint, Photoshop and other popular graphics programs.
But NOAA, in addition to offering free digital charts and Coast Pilots, has free scientific climate and mapping software available. One of these Windows-based programs is called Chart Reprojector. Its purpose is to change an RNC’s projection and datum and convert it into a file that can be used with Geographic Information System software.
Unless you’re a map geek you’re probably scratching your head at what all that means. Don’t worry. If you’re an average kayaker interested in creating your own custom charts, all you need to know is Chart Reprojector has an easy-to-use feature that can turn an RNC into a TIFF graphics file, a common format that can be opened by your favorite graphics editor. (I personally like a free Windows program called Paint.NET that you can download from: www.getpaint.net.)
Once you’ve saved the chart as a TIFF file, you can do nifty things on your computer like add annotations, plot course lines, crop parts of the chart you don’t plan on using, or rescale the chart to a smaller size. The chart is just like any other graphics file and you can edit it to your heart’s content, limited only by your artistic abilities.
Using Chart Reprojector, as shown in Figure 1, is a snap—if you’re a Windows user, that is, unfortunately there’s not a version for Macs. First, download a copy from: www.csc.noaa.gov/crs/chartreproj.html. It comes as a compressed .ZIP file so you’ll need to extract all of the files to a new folder. Once you have, run the SETUP.EXE program to install.
To save an RNC as a TIFF file, start the program and:
1. Use the Browse button under Input File to select the chart you want to convert. When you download an RNC, it’s conveniently named with the same number that identifies the paper chart version. Select a file with a .KAP extension, which contains the chart image data. When the file loads, information about the chart is display in Input Info.
2. Specify a name for the TIFF file in the Output File text box. You can use the Browse button to choose a folder where you want the file to be saved.
3. In the Output Info section, select TIFF as the File Format. Don’t change the other settings.
4. Click the Run button. The program will chug away, showing you how much of the conversion is left to go. The entire process should take less than a minute.
That’s all there is to it. You can now open the TIFF file with a graphics program. Keep in mind that a full-size chart can be pretty big, and if your computer doesn’t have enough memory a graphics editor may complain when you try to load the file. If that happens, get a copy of a free Windows program called IrfanView (www.irfanview.com). It’s a versatile graphics utility that can read large TIFF files. With it you can copy a portion of the chart and paste it into your graphics editor. You can also crop or rescale the chart to reduce its file size.
If you’re paddling outside U.S. waters, Canadian nautical charts, as well as digital charts from many other countries, currently use copy protection on their versions of RNCs. Unfortunately, Chart Reprojector won’t work with these protected files.
Rescaling and Grayscaling Recommendations
One of the downsides to using Booklet-Charts and other 8.5 x 11" charts is that they don’t give you a big picture view at a single glance—drawing a compass course line that extends over several pages can be kind of a pain.
A way to deal with this is to use a larger, yet still reduced scale version of the chart. Some chart vendors offer more manageable 2/3 sized (24 x 36"), black-and-white copies of charts at around half the cost of the full-size, color originals. Once you’ve converted an RNC to a TIFF file with Chart Reprojector you can make the same thing yourself, and usually for less money.
First, save a copy of the converted chart in a grayscale shade that still allows you to easily differentiate chart features —IrfanView is a great tool for this. Then put the TIFF file on a CD-ROM or USB thumb drive and head to a local print or copy shop that has a large-format copier —commonly used for printing blueprints. Tell the clerk you want to make a reduced size copy of the TIFF file. I’ve found you can shrink a chart down to 18 x 24," a common paper size, and still have it usable. Large format color printing is a more expensive option and you’ll probably be looking at prices exceeding an official NOAA paper chart.
There you have it. Between Booklet-Charts and RNCs you can become a do-it-yourself cartographer and start making your own kayak-friendly, cheap charts. And be sure to check back in on the NOAA chart website every now and then. The agency is planning some cool enhancements for their electronic chart products and services in the very near future.
Joel McNamara has been sea kayaking since the mid-1980s and is the author of GPS for Dummies. |
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