Summary

This document presents lessons related to Open Geospatial Consortium (OGC) protocols that were learned in the course of developing the OGC-Geoscience Gateway. The OGC-Geoscience Gateway is a NASA Advancing Collaborative Connections for Earth System Science (ACCESS) project that provides a gateway between the OGC protocols and technologies widely used within the geosciences community, in this case Thematic Real-time Environmental Distributed Data Services (THREDDS). The gateway allows a user to query a THREDDS catalog using the OGC Catalog Service for the Web (CS/W) protocol, making THREDDS-served data accessible to CS/W-aware geographic information service (GIS) clients. Since THREDDS provides OGC Web Coverage Service (WCS) access, our end goal was to search THREDDS catalogs for WCS coverages in a GIS Client that could then seamlessly acquire the WCS coverage for display. Although this goal was only partially realized, several valuable lessons were learned with respect to CS/W interoperability, particularly with its sibling WCS protocol. We hope these lessons will be useful to OGC client developers, as well as OGC interoperability architects.

Status

This document has been deprecated and is for informational purposes only.

The Interoperability between OGC CS/W and WCS Protocols was recommended for informational use as a lessons learned on March 2009.

NASA Earth Science Community Recommendations for Use

Strengths

Interoperability prototypes such as those described in this technical note are of fundamental importance in helping developers and system architects understand the issues involved in bridging related science domains both in terms of protocols as well as information schemata. Users cite the following uses for these technical notes:

“…they each provide great information to help investigation of these described services.” “These tech notes were informative to me and boosted my confidence in discoveries I had made regarding these services.” “This document describes a useful scenario to bridge Earth science community standards with OGC standards and combine CS/W and WCS together”

Weaknesses

Ideally, developers would have liked to have source code and schema mapping files to work with, however as the prototypes described in this technical note were not billed as open-source, the issue of code sharing was not applicable.

Applicability

As already mentioned, this technical note not only aids developers who may be either in the process of developing similar gateways or contemplating developing them, understand the issues involved, but also help information architects and specification implementers “measure the maturity and shortcomings of standards”. NASA centers that have data to share are looking at alternate ways to serve up their data holdings and one way to do this is via application gateways and protocol translators such as those described in this technical note, to make these data available seamlessly, with a wide variety of clients.

Limitations

The reviewing group realized that reviewers would request that some of the shortcomings in the underlying standards on which the prototypes were built, be fed back to the standards body, i.e., OGC. While the RFC authors did indeed itemize these issues and suggest alternate implementation approaches, recommending changes to an existing standard, published by a standards body is currently limited to information exchange only. Ensuring that the changes are incorporated into these standards is currently outside the scope of the former Standards Process Group.