The Marine Management Organisation (MMO) has recently published the outcome of research it commissioned us to do that considered ways to map the value of shipping.
For this project, AIS data was invaluable.
Automatic Identification System (AIS) is a maritime navigation safety communications system adopted by the International Maritime Organization (IMO) to provide vessel information, primarily for the purposes of maritime safety.
All vessels equipped with an AIS transmitter send AIS-data which can be received by land based or satellite receivers. It is a legal requirement for AIS to be fitted to all vessels of 300 gross tonnage or more and all passenger vessels irrespective of size. AIS is also used by other smaller craft including some fishing and recreational vessels. The reception range of AIS from a shore based receiving station is around 20 nautical miles and is dependent on the strength of the transmitting signal and the height of the aerial.
The data is encoded into message type. The three basic sections are: 1) dynamic information such as the vessels position, speed and course, 2) static information such as the vessels name and number, 3) voyage information such as the vessel draught and destination.
The recording and display of AIS data provides a source of information which can be used to spatially represent vessel movements.
UK Data Standard for AIS processing and analysis
Dynamic AIS data broadcasts every two to 10 seconds whilst a vessel is underway. Vessels travelling faster transmit their position more frequently than when travelling more slowly. Vessels at anchor or moored, transmit every three minutes.
The most straightforward presentation of AIS information is to plot the vessel’s position each time it makes a transmission. Whilst this method of presentation avoids the need to create vessel transit lines, it can result in high vessel densities being associated with moored vessels or vessels at anchor.
At ABPmer we have developed an enhanced method of AIS processing and analysis. This has been adopted as the MEDIN data standard for presentation of AIS derived spatial data for marine planning by the Marine Management Organisation since 2013.
To create transit lines, from which vessel patterns and use of a sea area can be determined, we join location positions. This requires sequential decoding of AIS dynamic information, static information and voyage data to create a set of positions for a known vessel. From this, a track or transit line can be created.
To create the UK datasets, ABPmer processed 84 days of AIS data provided by the Maritime and Coastguard Agency, using the national AIS receiver network.
The 84 days of data was sampled from the first seven days of each month to provide an annual dataset that can be displayed daily, weekly or monthly as well as by vessel type.
This amounts to more than 300 million records, representing 15.8 million transits per year, or more than 16.6 million nautical miles of vessel transits within UK waters.
These resulted in routeing datasets can then be used to define commercial shipping patterns, fishing areas, recreational routes and offshore development areas.
By adding further attributes to the data, the use of different sea areas can be quantified.
Using mapped vessel movement information, developers, operators and regulators alike can understand the implications of both activities and infrastructure. Once vessel transits have been determined and verified, a wide range of analysis can be undertaken to assist the decision-making process, whether for site/route selection, marine planning or navigational risk assessment. This might be initial site selection, constraints mapping, routeing analysis or detailed site optimisation.
Quality and careful use of AIS data is key to ensuring decisions are based on credible and up-to-date information. Correction or justification of conclusions later can be time consuming and expensive, if the assessments are subsequently shown to be flawed.
Navigational risk assessments used to support marine developments need to present an accurate traffic picture. This is used as a baseline for the development’s impact assessment. Sometimes, depending on the scheme, site specific AIS data collection is needed to better characterise certain types of vessel activity.
Here at ABPmer we believe the increasing availability of AIS data will continue to revolutionise site selection, risk assessment and decision-making.
We have decoded and processed AIS data to both increase the evidence base on which to make decisions and support decisions themselves.
Selected examples of how we have applied processed AIS datasets
To discuss how AIS data and analysis can support your decision-making, contact Chris Jackson, Head of Data and GIS Solutions on +44 (0)23 8071 1856.