1. NetCDF Standards Working Group
NetCDF (network Common Data Form) is a data model for array-oriented scientific data, a freely distributed collection of access libraries implementing support for that data model, and a machine-independent format. Together, the interfaces, libraries, and format support the creation, access, and sharing of scientific data.
NetCDF has been formally recognized by US Government standards bodies: the NASA Earth Standards Data Systems Working Groups (ESDSWG) Standards Process Group (SWG) and the Data Management and Communications Committee of the NOAA Integrated Ocean Observing System. The goal of this standards effort is to have the NetCDF with CF (Climate and Forecast) Conventions recognized as an international standard for encoding georeferenced data in binary form.
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The OGC has developed a broad Standards Baseline. UCAR and the OGC believe that having netCDF included in that family will encourage broader use and greater interoperability among clients and servers interchanging data in binary form. Having already established netCDF as a standard for binary encoding is making it possible to incorporate standard delivery of data in binary form via several OGC protocols, e.g., WCS, WFS, and SOS. Establishing additional extensions specifications to the core netCDF encoding standard will accelerate that process and allow for more encoding flexibility. Work is already underway on extension to GML and OWS for delivery of data encoded in netCDF.
Additional netCDF data model extensions will be considered to improve the effectiveness and usability of netCDF datasets for OGC Community. One example is a recently released discussion paper on uncertainty conventions.
2. Purpose of this Standards Working Group
The purpose of this Standards Working Group is to progress the netCDF with CF-conventions to the state of an adopted standard. This will be achieved in two or more stages. The first stage will establish the core standard. The core standard will be based on the 09-122 discussion paper, "CF-netCDF Encoding Specification," submitting it as a candidate standard, processing the comments received during the public comment period, and ensuring that the standard is consistent with the OGC baseline and business plan and is backwards compatible with existing netCDF and CF documents and implementations already in widespread use within the mass market. Another document covering the CF conventions will be submitted as a candidate extension standard and will follow the same process. The core netCDF standard, together with the CF extension standard, are necessary elements of the CF-netCDF Encoding Specification.
Subsequently, additional extension standards covering additional extension standard such as ncML-GML metadata encoding, and CF-netCDF Application Programming Interface (API) may be considered at the discretion of the active SWG members.
3. Scope of Work
This SWG is focused on processing the CF-netCDF candidate standard submissions for the core standard and one extension for the CF conventions, coordinating the public comment periods for the core and the CF extension, and processing any comments received during the public comment periods. The final deliverable of the SWG will be a version of the candidate core standard and the CF extension for consideration by the membership.
3.1 What is out of scope?
This SWG will focus only on processing comments received during the 30 day public comment period for the core and CF convention extension. Subsequent Change Requests are therefore out of scope.
3.2 Specific Contribution of Existing Work as a Starting Point
The starting point for the work will be the draft CF-netCDF submission, which is based on the approved standard specification of the NASA Standards Process Group (SPG). This will be sent out for public comment following any edits required to meet candidate standard requirements.
3.3 How it is to be Determined when the Work of the SWG has been Completed?
The work of the SWG will be complete when:
- All comments submitted during the 30 day public comment periods for the core standard and CF extension have been dealt with to the satisfaction of the SWG.
- The SWG approves the CF-netCDF Candidate Core Standard and the CF extension standard , for submission to the TC for approval as an adopted standard.
- The candidate standard has been approved by the OGC Technical and Planning Committees as an Adopted OGC standard.
4. Description of deliverables
The following deliverables will result from the work of this SWG:
- An annotated list of all comments submitted during the 30 day public comment periods for the core standard and for the CF extension -- including the comment, submitter, rationale, comment type/priority, and the response of the SWG.
- A final version of the CF-netCDF Core Standard and the CF extension standard for submission to the TC.
Core Standard Milestones: The timeline for the core standard. In recognition of the rapid product development cycles inherent in the mass market community, the SWG should conclude its activities on the core standard no later than Q1 2010. As such the following schedule of activities is planned for the core standard:
- SWG startup. 2009 October.
- OAB RFC review; SWG prepares candidate standard for vote for public release. 2009 October
- SWG votes to release CF-netCDF for public comment. 2009 November
- OGC staff develops PR and announces availability for public comment. 2009 November
- 30-day public comment period.2009 November - 2009 December
- SWG collects and collates comments into a single document. 2009 December
- SWG discusses and votes on comments and makes resulting edits towards final CF-netCDF candidate standard. January
- SWG votes to approve release of CF-netCDF candidate standard for approval as an OGC adopted standard. 2009 February
- 60 day IPR review period and associated TC e-vote to approve CF-netCDF candidate standard as .an OGC adopted standard. 2010 February - 2010 March
CF Extension Standard Milestones: A similar timeline is planned for the CF extension standard but it will be offset by 3 months.
Optional Additional Extensions: Additional extensions will be considered at the discretion of the SWG members. Timelines will be submitted at that time.
5. IPR Policy for this SWG
X RAND-Royalty Free.
6. Anticipated Participants
The target audience/participants of CF-netCDF includes search engine developers, GIS vendors, the geosciences research and education community, international government agencies that distribute and use global Earth observations and forecast, mass market software vendors interested in geographic based applications, and the consumer.
7. Other informative information about the work of this SWG
a. Similar or applicable standards work (OGC and elsewhere). The following standards and projects may be relevant to the SWG's planned work, although none currently provide the functionality anticipated by this committee's deliverables:
NASA Earth Systems Data Systems (ESDS) Standards Process Group (SPG) RFC-011: NetCDF Classic and 64-bit Offset File Formats
OGC Geography Markup Language v3.2 (also ISO 19136)
The SWG intends to seek and if possible maintain liaison with each of the organizations maintaining the above works.
b. Details of the first meeting The first meeting of the committee will be held by telephone conference call at 8AM 2009 October 14. Call-in information will be provided to the SWG's e-mail list and on the portal calendar in advance of the meeting. c. Projected on-going meeting schedule
The work of the committee will be carried out primarily by email and conference calls, every other week, with face-to-face meetings at each of the OGC TC meetings. Other face to face meetings may be called if this can expedite the work of the SWG.. d. Supporters of the Proposal The following people support this proposal and are committed to the Charter and projected meeting schedule. These members are known as SWG Founding or Charter members. Once the SWG is officially activated, this group is immediately "opted-into" the SWG and have voting rights from the first day the SWG is officially formed. Extend the table as necessary.
University of Reading
UK Met Office,
Marie Francoise Voidrot
e. Convener(s) Ben Domenico, Unidata (NCAR)