Don't overlook the seemingly obvious fact that you must have navigation software to view electronic charts. Just as you can't open a PDF file without Adobe's Acrobat Reader and you can't open a DOC file without Microsoft Word, the same logic applies to an electronic chart: you can't open a BSB file without one of the navigation applications designed to display BSB files.
Navigation software comes in many flavors and this series will test and review each of the major products on the market in coming weeks. For now, we'll simply say that there are a wide variety of packages in many price ranges, including software from Nobeltec, Maptech, Raymarine, Rose Point and other companies, and that some of these manufacturers offer a trial version on their website. Trial versions, or demoware, are either time limited or have certain functions disabled, but they are a great way to test out products before you spend money. Another option is free software, such as CARIS Easy View and SeaClear II.
THE STORY ON FREE CHARTS
The last component is the charts themselves, and here we will drill down a bit. Changes in the availability and price of nautical charts have fueled the drive toward computer-based navigation, and understanding what is available and how it is evolving is essential if you plan to setup a system.
For starters, the data that we see on charts for U.S. waters is almost universally provided by the federal government, specifically the National Oceanic and Atmospheric Administration, known as NOAA (pronounced no-uh). You may be looking at a chart product purchased from a company, but the majority of the data on that chart was probably provided by NOAA. The reason is simple: the federal government is the only organization that has the resources to collect that much information and keep it reasonably current.
NOAA has made paper charts available for decades, but it wasn't until 1995 that it began offering charts in digital form. It did so through a partnership with Maptech Inc., which sold the charts in a trademarked format known as "BSB." Other companies had competing products, but Maptech was the only official supplier of NOAA charts.
One criticism of the arrangement is that the charts were relatively expensive, causing boaters to keep the same charts for years in order to avoid spending money for an update. When NOAA's agreement with Maptech expired in 2005, the agency made its catalog of roughly 1,000 charts covering all U.S. waters available for free via download from its website, and took other steps to get accurate digital charts into the hands of boaters. (For a story on how free charts came about, see link below).
Raster charts are scanned images of paper charts. They are popular because of their familiar appearance, but zooming in tight is problematic because the chart is a static image. Zoomed objects are subject to overscale and pixelization, as shown.
With free charts online, why isn't every boater carrying the latest up-to-date charts in electronic format? That is NOAA's goal, but a few hurdles remain before computer-based navigation becomes universal.
RASTER VERSUS VECTOR
The format of electronic charts, namely raster or vector,is an important distinction to understand, because it will affect what you see on your laptop screen and, more importantly, how you use the charts on the water.
Raster Navigational Charts, often called RNCs, are scanned digital images of NOAA paper charts. Each chart is basically a color copy comprised of millions of "picture elements" or pixels, saved as a large file.
Vector charts, known as Electronic Navigational Charts or ENCs, are a database that contains objects,points, lines, polygons, symbols and other data, that correspond to the features on a chart. Each data point is located by its latitude and longitude, and is linked to a list of attributes. For example, a navigational aid may be associated with attributes such as location, number, height and light color.
