The WXCM-WXXM-WXXS are based on internationally agreed standards and specifications:
The WXCM and WXXM are 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.
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.:
As such, GML provides the building blocks for representing features, properties and geometries.
The power of GML is that it allows WXXM 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.
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.
Therefore, the ISO standards provide a well thought out foundation for building a geographical data exchange specification such as WXCM-WXXM.
By using the ISO standards, WXXM gains the following benefits:
- Increased global interoperability with other design standards
- Improved data modelling by leveraging analysis and design decisions developed by the ISO TC211 committee
- Standardised data models for temporality and geometry
- Cost and efficiency improvements by leveraging COTS tolls and products that are also based on the ISO standards
This standard specifies an XML implementation for the OGC and ISO Observations and Measurements (O&M) conceptual model (OGC Observations and Measurements v2.0 also published as ISO/DIS 19156), including a schema for Sampling Features.
This standard defines XML schemas for observations, and for features involved in sampling when making observations. These provide document models for the exchange of information describing observation acts and their results, both within and between different communities