Global Ship Traffic
Global Ship Traffic
Posted January 28, 2013
Voyager now includes an overlay of global ship traffic. You can find this by selecting “ship routes” under the “navigation” category of the left-hand overlay selection menu. PacIOOS derived this map from Automatic Identification System (AIS) position reports that many ships transmit during their travels for the security and safety of maritime transportation. Global ship traffic is aggregated over August 2011 through mid-August 2012 at 10 km resolution.
We have also updated the existing Hawaiʻi ship traffic overlay with finer map detail and flexible tools for customizing the map appearance. As before, this is an aggregate of AIS position reports over 2008-2009. Using the same “ship routes” overlay, you can switch between either the “Global” or “Hawaiʻi” overlays. Each provides reasonable defaults but allow the user to change colors, bands, stretch, and opacity as desired. Clicking on the map also lists the number of AIS reports aggregated at that pixel location and provides links for viewing the overlay in Google Earth or using a Web Map Service (WMS) GetMap URL.
These data represent total AIS position reports, not total number of ships. While useful for mapping areas of relatively high versus low shipping activity, these data should not be interpreted as the total number of ships that have visited each pixel location: a ship may transmit its position repeatedly at the same location, such as when it is anchored.
Because of license restraints with ORBCOMM (global) and the U.S. Coast Guard (Hawaiʻi), these layers are provided only as images (via WMS) while the underlying source data are restricted. For more information on these and other AIS data that PacIOOS provides, please visit: http://oos.soest.hawaii.edu/thredds/idd/ais.html.
