Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and international waters in real-time. This dataset represents the density of tug and towing vessel traffic in 2011 for the contiguous United States offshore waters from tug or towing vessels with AIS transponders in 100 meter grid cells. The dataset is best interpreted using a high to low density scale and does not represent actual vessel counts.

Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and international waters in real-time. This dataset represents the density of cargo vessel traffic in 2013 for the contiguous United States offshore waters from cargo vessels with AIS transponders in 100 meter grid cells. The dataset is best interpreted using a high to low density scale and does not represent actual vessel counts.

Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and international waters in real-time. This dataset represents the density of tanker vessel traffic in 2013 for the contiguous United States offshore waters from tanker vessels with AIS transponders in 100 meter grid cells. The dataset is best interpreted using a high to low density scale and does not represent actual vessel counts.

Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and international waters in real-time. This dataset represents the density of vessel traffic in 2013 for the contiguous United States offshore waters from vessels with AIS transponders in 100 meter grid cells. The dataset is best interpreted using a high to low density scale and does not represent actual vessel counts.

Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and international waters in real-time. This dataset represents the density of tanker vessel traffic in 2011 for the contiguous United States offshore waters from tanker vessels with AIS transponders in 100 meter grid cells. The dataset is best interpreted using a high to low density scale and does not represent actual vessel counts.

Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and international waters in real-time. This dataset represents the density of passenger vessel traffic in 2011 for the contiguous United States offshore waters from passenger vessels with AIS transponders in 100 meter grid cells. The dataset is best interpreted using a high to low density scale and does not represent actual vessel counts.

Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and international waters in real-time. This dataset represents the density of fishing vessel traffic in 2013 for the contiguous United States offshore waters from fishing vessels with AIS transponders in 100 meter grid cells. The dataset is best interpreted using a high to low density scale and does not represent actual vessel counts.

Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and international waters in real-time. This dataset represents the density of fishing vessel traffic in 2011 for the contiguous United States offshore waters from fishing vessels with AIS transponders in 100 meter grid cells. The dataset is best interpreted using a high to low density scale and does not represent actual vessel counts.

Automatic Identification Systems (AIS) are a navigation safety device that transmits and monitors the location and characteristics of many vessels in U.S. and international waters in real-time. This dataset represents the density of pleasure craft and sailing vessel traffic in 2011 for the contiguous United States offshore waters from pleasure craft or sailing vessels with AIS transponders in 100 meter grid cells. The dataset is best interpreted using a high to low density scale and does not represent actual vessel counts.

These data were generated to provide insight into marine traffic patterns on a macro scale so they could be analyzed across the coastal waters of the Continental United States, this data set is for the UTM Zone 10S. For this dataset a transit is counted for every unique vessel intersecting a 1 kilometer square grid cell each day. This data represents the total number of vessel transits from October 2009 - October 2010. Some grid cells were unable to be processed, but this does not interfere with the integrity of this dataset. Please note multiple connection errors occurred during the time frame of this study. In most cases data gaps were filled by making subsequent request to the coastguard or other groups receiving the same data feed. However, due to resource constraints uninterrupted coverage was not obtained. Overall data outages were minimal on the order less than a day per month and because random and affect all areas uniformly do not has a significant effect on the integrity of the data. Also as stated on the USCG NAIS website AIS data is not representative of all vessel traffic and USCG NAIS receivers do not fully cover the entire extent of this study area. Please take time to understand both of these limitations.