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THREDDS Data Server

Overview

The THREDDS Data Server (TDS) is a web server that provides metadata and data access for scientific datasets, building on existing technologies and protocols:

  1. THREDDS Dataset Inventory Catalogs are used to provide virtual directories of available data and their associated metadata. These catalogs can be generated dynamically or statically.
  2. The Netcdf-Java library reads NetCDF, OpenDAP, and HDF5 datasets, as well as other binary formats such as GRIB and NEXRAD into a Common Data Model (CDM), essentially an (extended) netCDF view of the data. Datasets that can be read through the Netcdf-Java library are called CDM datasets.
  3. TDS can use the NetCDF Markup Language (NcML) to modify and create virtual aggregations of CDM datasets.
  4. An integrated server provides OPeNDAP access to any CDM dataset. OPeNDAP is a widely used, subsetting data access method extending the HTTP protocol.
  5. An integrated server provides bulk file access through the HTTP protocol.
  6. An integrated server provides data access through the OpenGIS Consortium (OGC) Web Coverage Service (WCS) protocol for any "gridded" dataset whose coordinate system information is complete.
  7. An integrated NetCDF Subset Service allows subsetting of THREDDS datasets, using earth coordinates (such as lat/lon bounding boxes and date ranges) and returns netCDF binary files, XML or CSV ascii. This is a prototype, please do not rely on the APIs until announced as ready for use.

The THREDDS Data Server is implemented in 100% Java, and is contained in a single war file, which allows very easy installation into the open-source Tomcat web server. Configuration is made as simple and as automatic as possible, and we have made the server as secure as possible. The library is freely available and the source code is released under the GNU Lesser General Public License (LGPL).

Much of the realtime data available over the Unidata Internet Data Distribution (IDD) is available through a THREDDS Data Server hosted at Unidata on motherlode.ucar.edu. You are welcome to browse and access these meteorological datasets.

System Requirements

Download

Documentation

THREDDS Catalogs

THREDDS Catalogs are logical directories of on-line data resources, encoded as XML documents, which provide a place for annotations and other metadata about the data resources to reside. This is how THREDDS-enabled data consumers find out what data is available from data providers.

THREDDS Catalogs were originally designed for clients to use to access remote data. They have been extended to allow the TDS to use them for its own configuration. In this mode they are called TDS Configuration Catalogs, or server-side Catalogs. They contain information needed only on the server, which is removed when the TDS sends the catalog to the client, called the client-side or client-view catalog.

The TDS dynamically generates THREDDS catalogs based on the TDS configuration catalogs. For more information:

For client-side catalogs, the current specifications are:

Other TDS Services

Other ways to use TDS

 

This document is maintained by John Caron and was last updated on Feb 04, 2008
 
 
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