What does the file name of the NOAA ENC® mean?
Answer – The NOAA ENC® file name format is specified in the IHO S-57 standard. The first two characters, US, indicate that the U.S. Office of Coast Survey, NOAA, produced the NOAA ENC®. The third character indicates the “navigational purpose” of the NOAA ENC® as defined in S-57, a rough indicator of the scale of the NOAA ENC®: 1-overview; 2-general; 3-coastal; 4-approach; 5-harbor; 6-berthing. The remaining characters left of the dot are defined by Coast Survey. The fourth and fifth characters are the two letter postal code for the state where the NOAA ENC® is located (e.g., TX for Texas, NY for New York, etc.) The next two characters are the NOAA ENC®s number and the final character is “M” indicated that the NOAA ENC® is in metric units. The file extension, “.000,” for a base NOAA ENC® cell is used for updating. The first update for a cell will be “.001” the next “.002” and so forth.
