Progress in Improving Access to Earth Observation Data

Over the past three years the Committee on Earth Observation Satellites (CEOS) Working Group on Information Systems and Services (WGISS) has undertaken a project to improve the discovery and access of the environmental satellite data products that are held by its member agencies. This effort was initiated in response to the objective of the intergovernmental Group on Earth Observations (GEO) to harmonize access to all environmental data by adopting and using the set of data system standards and conventions of its Global Earth Observation System of Systems (GEOSS). Because the CEOS agencies had already implemented data systems to support access to their respective collections, changes to those individual systems presented a major barrier to attainment of the GEO goals. Further, even if discovery and access pathways were developed to each individual system, the end users would still be confronted with the task of filtering and integrating result sets from across disparate systems. WGISS developed the concept of a community brokering capability, the CEOS WGISS Integrated Catalog (CWIC), which would be able to interface with GEOSS according to its prescribed standards while leveraging the underlying agency data systems with minimal impact. It would also enable the CEOS members to harmonize their approach in providing their information and data products to the general user community as they extend and advance their data system services. CWIC consists of a mediator that uses the OGC Catalog Service for the Web (CSW) Version 2.0.2 in the dialog with the GEO Portal and other CWIC clients. The mediator transmits high-level discovery requests to the CEOS International Directory Network (IDN) to retrieve data collection level metadata. To identify data that satisfies specific space/time/keyword search criteria, the mediator passes the request to the appropriate data system wrapper(s) that can translate the request and response between CSW and the local system standard. The search results are based on ISO 19115 metadata. In the cases where the data system is using the CSW the request and response are transmitted directly between the mediator and the target data system. CWIC currently exists and has been demonstrated as a prototype capability with five member agency data partners and several client partners. A number of additional data and client partners are in various stages of development and others are considering participation. As the project completes its prototype development phase it is beginning to address the challenge of providing a sustained operational capability. It is also looking at the potential for harmonized approaches and conventions for search and results metadata and for user registration and authorization. Working together the WGISS members are developing this needed capability for the CEOS community that in turn serves as an invaluable component of the GEO system of systems.