A Geospatial Data Services Infrastructure for Science and the Environment

The Constellation project provides a complete solution for the management, discovery, exploitation, and distribution of geographic data within a distributed services framework based on standards compliant, free software modules.

The project follows well defined standards based on, for geographic data, the specifications of the Open Geospatial Consortium (OGC) and the International Organisation for Standardisation (ISO) and, for software development, the specifications of the Java computer language as developed within the Java Community Process.

Constellation uses a fully modular architecture which enables a completely flexible re-assembly of components to target a wide range of applications in diverse fields.

The very concept of a Spatial Data Infrastructure depends inherently on the use of Web Services for geographic data which follow the accepted norms and specifications since that is required to guarantee interoperability. To enable the standards compliant development of Geospatial Web Services within an SDI, Constellation is based on several core components, all of them free software:

Metro: the project regroups most of the core Java specifications related to WebService handling such as JAX-WS to handle SOAP based services and JAX-RS (Jersey) for RESTful services.
JackRabbit: the reference implementation of the Java Content Repository specifications (JSR-170 and JSR-283) which define a standardized interface as an abstraction layer for the management and use of heterogeneous data.
GeoAPI: a collection of Java language interfaces for the OGC and ISO geospatial specifications, which is itself a formal OGC specification and is currently aiming to gain its own "Standard Working Group" within the OGC.
Geotools: a library of components for the complete handling of geospatial data which provides, among other components, the reference implementation of the GeoAPI interfaces.
JScience: the reference implementation of the Java specification for units of measure (JSR-275), providing the rigorous handling of units and their conversion.

This modular architecture, the strict respect for accepted norms, and the distribution of all software components under the standard free software license for the Java language jointly guarantee to implementers who base their services on Constellation the fullest flexibility for service development and the long term persistence of their services within their spatial data infrastructure.

Scientific focus
The Constellation project originates from the scientific community so the project pays particular attention towards preserving data integrity and clearly defining any manipulation performed on those data.

Quality code
The scientific focus also pushes the Constellation project to maintain a high level of quality in all the code used throughout the project. All code is written with attention to details of the Java language. Source code is also extensively documented to explain its inner workings. The source code is free software, published in the open so any user can discover exactly how Constellation treats their data.