By Tom Lochhaas
Vector charts, also called ENC charts, are a graphic format in which charts are presented in a more schematic manner. Compare the app screen shot of the vector chart above (from the Navionics app) with the equivalent raster chart app screen shot on the preceding page (from the Memory-Map app). The screen presents less information about land and other features, and water depths are presented more by color layers than by soundings. As you zoom in, the information changes, however - it doesn't just get larger as on a raster chart zoom. You will see more depth soundings, for example, but the type used will always be the same. (If a number is hard to see on a small smartphone screen, it won't get any larger when you zoom in.)
The advantages of vector charts include:
The disadvantages of vector charts include:
Overall, the choice between raster and vector charts is mostly a matter of personal taste, since both are generally equally accurate and reliable for electronic navigation. Many software programs include both and give you the choice, whereas most apps use only one or the other, making it an important decision before choosing the app.
Speaking just for myself, I prefer raster charts because of all the information presented and the familiar appearance matching my paper charts - and I'm willing to work around the disadvantages. But I've sailed much with others using vector charts and understand their appeal as well. Most important, read reviews of different navigation products before making your own choice.