Office of Coast Survey
National Oceanic and Atmospheric Administration
U.S. Department of Commerce

Find Nautical Charts

Office Coast Survey

We are the nation’s nautical chart-maker. We are responsible for upgrading charts, surveying the seafloor, responding to maritime emergencies, and searching for underwater obstructions that pose a danger to navigation.


What’s the difference between an ENC and an RNC?

What’s the difference between an ENC and an RNC?

Raster Navigational Chart (RNC)
Electronic Navigational Chart (ENC)

The NOAA Office of Coast Survey (OCS produces two kinds of digital charts; Raster Navigation Charts (RNC’s) and Electronic Navigational Charts (NOAA ENC).

A Raster Navigational Charts is an accurate digital image comprised of pixels, displayed on an electronic screen. Each pixel has a unique color or it has no color. The pattern of the colored and the empty pixels gives shape to the individual features of the chart. The better understand the nature of raster charts, we examine the process that creates them.



Revised: 11/15/2017