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Historical data requests can require substantial expenditure of time and/or level of effort (LOE) to produce data, depending on the nature of the request. The Navigation Center (NAVCEN) is capable of providing requested data in several formats. In addition to the standard graphic formats (.PNG, .JPG, .TIF, .PDF), below is a detailed list of other available formats, which could be produced based on the requestor’s particular needs. Providing shape-files could reduce the LOE to process each request for a specific area. Please note that NAVCEN does not provide any applications to parse, query, and display the data. It is up to the requestor to obtain the necessary application(s) through their chain of command or IT Support staff.

You may click on the image to the right of each description to view the enlarged example in a separate window.

Raw AIS NMEA Data File: These files contain actual data as received from the AIS network in 6-bit ASCII format. Raw AIS data request requires the lowest LOE. The requestor will need to obtain an AIS converter application in order to properly view the data (various applications can be found on the Internet). Once converted, the requestor can incorporate this data into other applications to parse, query, and display the data.

Click to enlarge image.

.CSV File: Comma Separated Values (CSV) format is the most user-friendly, as these files can be viewed in any spreadsheet, database or text viewer application. Data is provided with column headers identifying the various fields. Messages and message fields desired can be tailored to individual requests. Please note data delivery via .CSV format requires additional processing time (LOE) as compared to the Raw NMEA Data Format.
Click to enlarge image.

Heat Maps (Density Plots): Data requested can be displayed in a graphic image called a heat map. For example, the image to the right is a density heat map of the coast of Delaware, where the various intensities of colors represents the density (i.e. the number per cell) of vessel tracks for the entire month of February. Providing the cell size/dimension of box, the resolution output, as well as any shape files for the geographical area you are requesting helps us to ensure your request is processed as accurately as possible. Please note, density plots do not include vessel specific data.

(This data product is created for government agencies and will not be created solely to fill FOIA requests.)
Click to enlarge image.

Standard Graphics Format (.PNG, .JPG, .TIF, .PDF): Historic data can be presented in various static graphic images that can be viewed and incorporated in many applications, such as word processors, spreadsheets, and slide shows. The image to the right depicts multiple vessels tracks over the course of a day in the San Francisco area.

(This data product is created for government agencies and will not be created solely to fill FOIA requests.)
Click to enlarge image.

KML Animation: This format allows customers to view a limited number of vessel tracks as recorded by the AIS during a specified time range in a given geographic area. This format allows for data of a vessel(s) in the specified time range. Typically, these files are viewed in Geographic Information System (GIS) applications (e.g., ArcGIS Explorer or GoogleEarth), which may be available for download at various internet sites.

(This data product is created for government agencies and will not be created solely to fill FOIA requests.)

Click to enlarge image.

Historical Data Request LOE/Processing Time Example: Below is an example of a basic data request with estimated processing times per data format. Please keep in mind that the processing times may vary depending on the actual request type, the approval process, the amount of data involved, and availability of staff.

Request Details
  •  MMSI: 30 specific vessels
  • AIS Message Types:1-3, 5, and 18
  •  Geographical area of interest:40.746, -74.278; 40.117,-74.278;40.118,-73.448; 40.746,-73.448
  •  Period of Interest: 02/1/11– 2/28/11
Type of Request (Format) Estimated LOE/Processing Time (Business Days) After Approval
AIS NMEA Format 7 days
CSV Data Format 7 to 10 days
Heat Maps 5 to 7 days
Standard Graphics Format (PNG, GIF, JPEG, PDF) 5 to 7 days
KML Animation 7 to 10 days