All IOOS Data Providers must establish, register, and maintain standards-based Data Access Services that provide data in common, community-established formats. All IOOS data and products must be served through these DMAC recommended services, depending on the data type as outlined in Requirements. Optional service types listed below may be deployed at the discretion of the data provider for relevant data types. Alternative or legacy services not mentioned specifically (eg. Esri REST) that data providers wish to support are not disallowed or discouraged, but are not covered by this policy.


  • All data and products must be made available via data access services, and registered in the IOOS Catalog.
  • For in-situ observations (including point, profile, trajectory, timeseries, or other sampling types), or for other tabular data types, ERDDAP-TableDAP is required. THREDDS OPeNDAP with ncSOS enabled for SOS is optionally recommended.
  • For gridded data (e.g. model output or remotely-sensed products) OPeNDAP with WMS enabled is required.  ERDDAP-GridDAP for supported regular grid types is optionally recommended.

Standards, Formats and Protocols

Implementation Methods/Practices

Available Software:

  • ERDDAP: NOAA Southwest Fishery Science Center’s Data Server
  • THREDDS: Thematic Real-time Environmental Distributed Data Services
  • ncSOS: SOS service extension for THREDDS for netCDF CF Discrete Sampling Geometry datasets
  • ncISO: ISO metadata service for THREDDS
  • OPeNDAP Hyrax Data Server

IOOS Compliance Checker

The IOOS Compliance Checker is a command line Python tool to check local/remote datasets against a variety of compliance standards, including community standards such as netCDF-CF, ACDD, and the IOOS Metadata Profile. For non-python users, there is also a Compliance Checker website where files can be individually run through the checker.


In situ data shall be made available via ERDDAP-TableDAP, with ERDDAP datasets adhering to the IOOS Metadata Profile 1.2. For IOOS Catalog registration requirements, ERDDAP includes native support for ISO 19115-2 metadata output for all datasets it serves.  Alternatively, THREDDS combined with ncSOS allows publishing of netCDF-CF Discrete Sampling Geometry in situ datasets in both OPeNDAP and SOS service types. 

For biological datasets or other datasets that are commonly tabular in format, ERDDAP TableDAP should be deployed.

Gridded datasets, such as model output and remotely-sensed products, shall be made available via OPeNDAP and WMS.  THREDDS is the recommended software to support this requirement, however THREDDS, ERDDAP, and Hyrax all support OpenDAP.   Data providers deploying THREDDS should enable all THREDDS extensions to provide maximum interoperability and service types.  For example, for IOOS Catalog registration considerations THREDDS users should also enable the ncISO service to publish ISO 19115-2 metadata.