Updates

Automatic Identification System (AIS) Announcements

The following are updates and announcements for AIS users:

  • User names and passwords will now expire one year after being issued.
  • Please read the AIS standards and specifications provided by the Coast Guard to learn what are valid domains and other content issues for each field.
  • The metadata for 2009, 2010 and 2011 reports that the speed over ground (SOG) and the course over ground (COG) values are at a resolution of 1/10ths of units; the unit resolution should read “whole units”. These are knot and degree values respectively.
  • Some users report errors when using the Track Builder tool under certain circumstances. Our testing indicates this is caused when low-level geoprocessing tasks get completed before the hard disk device is available. Configurations with higher speed (10,000 RPM) disks do not exhibit this error.
  • The Filter and Format tools that are used to process the raw NMEA provided by the Coast Guard use the AIS Parser written by Brian C. Lane.
Please remember, as noted in the metadata:
  • The June 2009 data set is incomplete
  • These data have been filtered to a one minute sample rate
  • The MMSI values for 2010 and 2011 have been encrypted at the request of the Coast Guard
For more information about AIS, visit the AIS Web page.