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Standards |
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AIXM is based on internationally agreed standards and specifications.
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The AIXM Conceptual Model is specified using the Unified Modelling Language (UML).
UML is a visual language for describing relationships, behaviour and high level ideas. It was originally intended for software engineering, but today UML is used for business process modelling, data modelling, requirements modelling and other activities.
UML offers a number of advantages as a modelling language. It is the de facto modelling standard with a well defined model structure and semantics. It has good industry support in the form of UML modelling tools and tools that can convert UML into useful products like XML schemas, databases and computer programs.
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The Geography Markup Language (GML) is an XML schema specification. It is an internationally adopted standard for exchanging geographical features.
The GML Schemas can express simple geometries, e.g.:
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Line |
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Point |
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Polygon |
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Surface |
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As such, GML provides the building blocks for representing features, properties and geometries. It is left to AIXM to define the features. AIXM does this by creating a GML Profile - it simplifies the GML by using only a limited set of GML features.
The power of GML is that it allows AIXM to leverage existing commercial tools and existing GML data sources to create a seamless GIS view. To illustrate this: EUROCONTROL’s SkyView tool can read and display GML from a variety of data sources. Simply by understanding GML, SkyView can display terrain, airspace boundaries, fixes and airports.
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The ISO Technical Committee 211 (TC211) is responsible for developing the ISO 19100 geographic series of standards. The purpose of these standards is to provide a common framework for developing domain specific standards based on geography. The ISO TC211 standards include temporal, metadata and spatial schemas. In addition, GML is scheduled to be integrated into the TC211 standards in 2007.
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Therefore, the ISO standards provide a well thought out foundation for building a geographical data exchange specification such as AIXM.
By using the ISO standards, AIXM gains the following benefits:
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Increased global interoperablity with other design standards
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Improved data modelling by leveraging analysis and design decisions developed by the ISO TC211 committee |
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Standardised data models for temporality and geometry |
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Cost and efficiency improvements by leveraging COTS tolls and products that are also based on the ISO standards |
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ISO 19115:2003 Geographic information - Metadata |
Metadata is information about data.
Metadata provides information about a particular dataset, such as the origin of the data, the citation for the resources, an abstract, the purposes, credits, the status and points of contact. As the goal of AIXM is to exchange all types of aeronautical information internationally in a standardised format, the data producer is able to send metadata along with each AIXM message.
ISO 19115 defines general-purpose metadata in the field of geographic information applicable to the cataloguing of datasets, clearinghouse activities, and the full description of datasets.
The essential purpose of a catalogue service is to enable a user to locate, access, and make use of resources in an open, distributed system by providing facilities for retrieving, storing, and managing many kinds of resource descriptions.
However, the purpose of AIXM is to exchange recurrent messages and move the state of information updates from less static to more dynamic. Hence, the structure of the AIXM metadata profile is based on ISO19115, with which it conforms to the largest possible extent.
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If you would like to read more about the standards, please follow the links on our Related Links page. It lists many sites that will be of interest.
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Last validation: 05/12/2006
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