Thematic Real-time Environmental Distributed Data Services (THREDDS): Incorporating Interactive Analysis Tools into NSDL

The overarching goal of Unidata's Thematic Real-time Environmental Distributed Data Services (THREDDS) is to provide students, educators and researchers with coherent access to a large collection of real-time and archived datasets from a variety of environmental data sources at a number of distributed server sites. The datasets will be conveniently accessible from a collection of THREDDS-enabled data analysis and display tools. THREDDS will provide real-time data delivery via reliable, event-driven "push" technology as well as transparent access to datasets using "pull" systems that make it possible to access data on remote servers as if they were on the user's own computer. The system will be built on a set of software components and data servers that are already in operation or under development. The heart of THREDDS is metadata contained in publishable inventories and catalogs (PICats). The creation, publication and distribution of PICats will be facilitated by the discovery system and services provided by DLESE. For example, sites receiving real-time environmental data can create PICats describing data products automatically as they arrive using decoders and crawlers. On the other hand, since PICats do not have to reside on the server with the data, researchers will be able to create PICats for online publications that point to datasets residing on several data servers. Similarly, educators will incorporate PICats of illustrative datasets into modules that also include tools for data analysis and visualization, and students will be able to use PICats to point to datasets related to their research projects, just as they now use URLs to point to relevant documents. This paper presents an overview of THREDDS and an update on the current status.