There are two different types of technologies used in electronic charting. Most chart plotters (like those from Magellan, Garmin, some Northstar models, and others) use vector enc charts, which bear little resemblance to regular paper charts, but have some real advantages.

In essence, ENC charts are a rendering of a lithographic chart in a point-by-point format. They allow you to zoom in to large magnifications without distortion. As a rule, the hardware that uses this technology is all-in-one units (aqua. chartplotters) that include a screen, a GPS, and a programmable interface. All you add are the chart cartridges. enc chart plotters generally cost between $500 and $2,000+. Vector chart cartridges (of which Navionics and C-MAP NT cartridges are examples) cost more, some time substantially more, than similar coverage on raster chart CDs.

Electronic Raster charts (RNC charts) have recently been made available from NOAA as they have contracted with MapTech to provide raster charts in BSB format which most all pc navigation software is capable of reading. This is great news as it now means both vector and raster charts are available, and free, for most all marine navigation software.

Proprietary charts have been around the longest and are produced by companies such as Maptech, Navionics, C-MAP and Nobeltec. Due to the nature of the evolution of hardware based chart plotters and marine navigation software most charts either work on chartplotters or software, but not both. This does seem to be changing recently as C-MAP charts will work with some software.