The THREDDS Data Server (TDS) is a web server that provides metadata and data access for scientific datasets, using OPeNDAP, OGC WMS and WCS, HTTP, and other remote data access protocols. The TDS is developed and supported by Unidata, a division of the University Corporation for Atmospheric Research (UCAR), and is sponsored by the National Science Foundation.

Some of the features available in the TDS:

  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/CDM 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 optional server provides data access through the OpenGIS Consortium (OGC) Web Map Service (WMS) protocol, for any gridded dataset whose coordinate system information is complete. This software was developed by Jon Blower (University of Reading (UK) E-Science Center) as part of the ESSC Web Map Service for environmental data (aka Godiva2).

  8. An optional ncISO server provides automated metadata analysis and ISO metadata generation.

  9. The integrated NetCDF Subset Service and related CDM Remote Feature Service allows subsetting CDM datasets in coordinate space, using a REST API. Gridded data subsets can be returned in CF-compliant netCDF-3 or netCDF-4. Point data subsets can be returned in CSV, XML, or CF-DSG netCDF files.

  10. The integrated CDM Remote Service provides index subsetting on remote CDM datasets, with the same functionality that NetcdfFile provides for CDM local datasets and DODSNetcdfFile provides for remote OPeNDAP datasets. CdmRemote supports the full CDM data model.

The THREDDS Data Server is implemented in 100% Java (writing to netCDF-4 files is supported through the netCDF C library only) , and is contained in a single war file, which allows very easy installation into a servlet container such as 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 (MIT-style) netCDF library license.

Much of the realtime data available over the Unidata Internet Data Distribution (IDD) is available through a THREDDS Data Server hosted at Unidata on thredds.ucar.edu. You are welcome to browse and access these meteorological datasets. If you need regular access to large amounts of data, please contact support-idd@unidata.ucar.edu.

System Requirements

Java 8 is necessary for production use of the TDS in all cases. Security upgrades are no longer being made to Java 7 or previous versions.

Be sure to keep up with the latest versions of Java and Tomcat for security fixes. This is required for publically accessible servers!


TDS 5.0 is the development release. It requires Tomcat 8 and Java 8.

TDS 4.6 is the stable release. It requires Tomcat 7+ and Java 7+.


THREDDS This document was last updated Nov 2015