Since the 1st January 2010, the presence of paper charts on board is no longer obligatory, provided they are replaced by electronic versions. This measure was dictated by the fact that more and more pleasure sailors are travelling with electronic charts. Still, no one is safe from electrical problems on board. All responsible sailors should take paper charts too, in case of emergencies.

Raster or vector mapping?

To make electronic charts there is a choice between two methods: scanning paper charts (making a copy: Raster charts,) or the vector. For the vector version, only the significant points of the chart are memorized. It is the software connected with the chart which then connects them with lines (vectors.) So even when zooming the coastline remains the same size (this is not the case with scanning, in which the coastline is magnified by zooming.) The software can also choose to bring up details on the precise level of zoom. For large views it reduces the map. This practice does not affect the map quality and permits additional
information to be added, on ports, photos… Scanned or vector, the charts are all issued by official sources (SHOM, British Admiralty…) If the Raster provides assurance in producing the
original document (with the quality due to the different hydrographic services,) the vector, of a chart, may produce errors. Whilst true of some early versions, the later versions are much more accurate. Note thatc Raster charts are only available on a computer. Card readers read only vector maps.

Vector maps

There are three made which share the market: Navionics, C-Map and Garmin. Each offers highly detailed global coverage. Garmin is the only GPS maker that possesses its own cartography service. It issues charts under the name Blue Chart. The latest version is quite innovative since it permits guidance, taking into account depth probes. If your route passes over a shoal, the guidance avoids it; an attractive feature but one that must be monitored with regard to navigation. Navionics is the first to propose seamless charts. With this function you move from one chart to another, if necessary changing the scale, without overlap or discontinuity. The Navionics Gold are charts in two simple dimensions. The platinum Navionics range offers, in addition, 3D views (aerial and underwater.) C-Map offre l'avantage d'être compatible d'une version à l'autre. Les lecteurs lisant les cartes C-Map NT+ lisent aussi le format C-Map Max C-Map offers the advantage of compatibility between one version and another. Readers read the C-Map NT and also the C-Map Max.



Read the electronic chart on a computer

With PC software associated with the cartography, we find the same functions as with a dedicated card reader with the added possibility to choose between two types of mapping: the vector and Raster. The possibilities offered with PC cartography are linked to the software. At the least everything concerning navigation (routes, waypoints, log etc.) are available, as well as all GPS related information and reporting the boat’s position on a map. The advanced software permits tidal calculations, currents, route based on the boat’s parameters, routing, weather, radar image overlay or aerial image with the chart. In fact, the possibilities are evolving with technology.


Professional advice

“When selecting cartography, it is necessary to ensure that the division of areas is compatible with the navigation zone, to avoid being forced to purchase two charts.”