Information superiority in the maritime environment


Additional Military Layers (AML) is a range of digital geospatial products designed to enhance situational awareness in the marine environment.

Endorsed by NATO and coordinated by the UKHO, AML provides tactical advantage in military and humanitarian operations by using geospatial intelligence. Offering a range of vector and gridded data sets, AML provides a unified, interoperable product that supports digital navigation, access and reach of maritime forces.

To provide feedback or to request further information on AML, please email aml@ukho.gov.uk.

Sample and Test Data


AML Sample Data

AML Sample Data (Representative Data) is available for download in zip files, prepared in accordance with Edition 1 of each of the six NATO-endorsed product specifications.

The Representative Data is real data, meaning that it is typical in size and volume and will only contain features and attributes relevant to the product type and availability of the source data in the area concerned. This data is not updated and is not intended for operational use.

For details of the content and coverage for each of the Base, New Edition and Update files, follow the link below.

Version 1.0 S-57 Base Exchange sets (Representative)

AML V3.0 Sample Data

AML version 3.0 AML trials data, produced by the German Bundeswehr, is now available for download using this link. This trials data comprises:

  • Bathymetric charts (CLB) in different scale bands - derived from the sea survey database of the German Hydrographic Office
  • Flight Aeronautical Information (FAI) - derived from NGA AVDAFIF
  • Military Flight Information (MFI) - derived from NGA AVDAFIF
  • Nautical chart background data (NCD) - derived from various German ENCs
  • Q-Route (QRT), Sediment data - derived from the German Mine Warfare data centre
  • One SBO cell containing fictitious data
  • One LBO cell containing fictitious data

AML Test Data

AML Standard Test Data, prepared in accordance with Edition 1 of each of the six NATO-endorsed product specifications, is available in self extracting zip files for download. This data is fictitious but contains at least one example of every feature class and  every possible attribute within the data model (although not all features carry the full possible attribution).

As well as S-57 Base Exchange sets (these also include New Editions); S-57 Update Exchange sets are provided in the same way. Please find details of the content and coverage for each of the Base, New Editions and Update files below.

Version 1.0 S-57 Base Exchange sets 

Version 1.0 S-57 Update Exchange sets 

Component 1, (Physical Climatology)

Test Data is available for IWC Component 1, Physical Climatology, compliant with Component 1 (Physical Climatology) of the IWC 2.0 specification. This data set is the latest GPPDB (Gridded Physical Properties Database) climatology containing temperature, salinity, sound speed and density at 0.25 degree spatial resolution, 32 depths levels and monthly temporal resolution. The spatial extent of this dataset covers the NW approaches. To request further information contact aml@ukho.gov.uk.

Test Data for IWC Component 1

Component 2 (Marine Mammals)

Test data for IWC Component 2, Marine Mammals, can be supplied as a single NetCDF file containing Marine Mammal Distribution data for 30 species present in the NW approaches (53-61N, 19-4W). All fields, variables and attributes defined in the IWC v2.0 specification and Annex are contained in the file (although some are unpopulated).

The data has a spatial resolution of 0.5 degrees and a temporal resolution of one month. Due to the design of the file, it has been necessary to repeat the RES and density data for each month. This does not result in repetition of data and larger file sizes, but does allow for refined RES and density estimates, incorporating temporal variations to be included at a later date with ease.

The delivered file is ~5.5Mb in size. This suggests that a global file containing 115 species at 0.5 deg resolution would be ~2.8Gb in size.

To request further information contact aml@ukho.gov.uk.

Test Data for IWC Component 2

Specifications and documents


AML Implementation and Guidance Document

This document has been produced to assist Directorates of Equipment Capability (DECs), Integrated Project Teams (IPTs) and contractors by providing guidance to the fundamental aspects of the AML concept, associated specifications/documentation and other known issues relating to the implementation of AML products.

Download the AML Implementation and Guidance Document here

Production Specification

NATO-endorsed Production Specifications (as distinct from the AML Product Specifications) describe details of how the content of any given AML data set should be encoded. This document covers the entirety of AML and is necessary to ensure that data sets are not only conformant to the AML Product Specifications, but also consistent in support of coalition interoperability.

Download the Production Specification here


Portrayal specification

A portrayal specification, providing display rules and symbols for AML vector product specifications (supporting all versions), was endorsed by the NATO GMWG and published in June 2018. This builds on the IHO S-52 Presentation Library 4.0.0 and is available as a .dai file. It is intended to be implemented in systems such as WECDIS to enhance the display and usability of AML products. To obtain this specification please email aml@ukho.gov.uk.


AML Product Specifications, Associated Documents


Product Specification

Carrier Annex

Product Specification

AML PS 3.0

Carrier Annex

AML PS Annex A 3.0

Product Specification

AML Feature and Attribute Catalogue v3.0.1


Draft (Unendorsed) Product Specifications

Draft (Unendorsed) Product Specifications

Gridded Sediment - Environment Seabed & Beach (ESB)
GS-ESB PS Annex C 1.0

AML Handbook

The NATO AML Handbook provides general information about AML, including a brief explanation of the products and benefits to users. It is produced by the UK Hydrographic Office (UKHO) on behalf of NATO and replaces the AML Handbook which was last revised in January 2012. The Handbook is held, maintained, configuration controlled, published and distributed in digital format.  Users are welcome to produce hardcopy versions for own use and for wider distribution, but should be aware that such hard copies will not be updated. Your contributions and comments are valued.  To make contributions or comments on the Handbook, or to request further information, please email aml@ukho.gov.uk.