What is the difference between raster (BSB) and vector (ENC) charts?
Many CHS charts are available in digital form in either raster (BSB) or vector (Electronic Navigational Chart) format. Both kinds of electronic charts enable a Global Positioning System (GPS) receiver to position your vessel on the screen in real-time, and both can make remarkable contributions to safer navigation. Raster charts are simply an electronic image of the paper charts, and provide no more information than a paper chart. Raster charts are digitized by scanning the paper chart. Each tiny segment of each line on a chart is converted to a raster picture element or pixel. These pixels are similar to a television picture or magnified newsprint in that they appear as dots on a grid. Beyond geo-referencing (allowing the cursor to sense the latitude and longitude of a vessels position), there is no intelligence inherent in the image. Many recreational boaters have adopted raster electronic charting systems because the charts are less expensive, and the navigation software required fo
