GRIB: Summary from the Encyclopedia of Graphics File Formats

GRIB File Format Summary

Also Known As: Gridded Binary


Type Various
Colors NA
Compression Uncompressed
Maximum Image Size NA
Multiple Images Per File NA
Numerical Format Binary bit-oriented
Originator World Meteorological Organization
Platform All
Supporting Applications Unknown
See Also BUFR

Usage
Transfer and transmission of weather and other data.

Comments
The GRIB format is outside the scope of this book, but we include a brief description because it is likely to be more useful in the future as interest in geographical information systems increases.

Vendor specifications are available for this format.


GRIB was created by the World Meteorological Organization (WMO) and is officially designated as FM 92-VIII Ext. GRIB (GRIdded Binary). It is designed to support fast computer-to-computer transmission of large volumes of data. Speed and efficiency are the key words here.

Contents:
File Organization
File Details
For Further Information

The format documentation is subtitled: "The WMO Format for the Storage of Weather Product Information and the Exchange of Weather Product Messages in Gridded Binary Form." Data in GRIB files, as the name suggests, is expected to be in gridded form, that is, arrayed in a rectilinear fashion. That this suggests our idea of a bitmap is no coincidence, although the WMO and its affiliates normally use the format for the transmission of observational data such as air pressure and temperature.

GRIB data streams and files adhere to the specification called "WMO Standard Formats for Weather Data Exchange Among Automated Weather Information Systems."

File Organization

GRIB files consist of a number of records, each of which may contain the following information:

  • Indicator section

  • Product definition section (PDS)

  • Optional grid description section (GDS)

  • Otional bitmap section (BMS)

  • Binary data section (BDS)

  • ASCII characters 7777

File Details

Detailing the internals of GRIB is beyond the scope of this article. GRIB is extremely complex and is, at this point, used in a narrow area of technology. This, coupled with the fact that the document is written in a dialect of government-ese, makes it tough sledding even for initiates. Nevertheless, if you need to understand the GRIB format, the document included on the CD-ROM should get you started. Good luck. Please note that the people who are responsible the GRIB documentation were as nice as could be.

For Further Information

For detailed information about GRIB, see the paper included on the CD-ROM:

Stackpole, John D., "The WMO Format For the Storage of Weather Product Information and the Exchange of Messages in Gridded Binary Form."

You can also get information from the University of Wisconsin NMS homepage:

http://java.meteor.wisc.edu/

Additional information on WMO data specifications can also be found in the following document:

Standard Formats for Weather Data Exchange Among Automated Weather Information Systems, Document Number FCM-S2-1990.

This document is available from:

U.S. Department of Commerce/National Oceanic and Atmospheric
Administration (NOAA)
Attn: Ms. Lena Loman
Office of the Federal Coordinator for Meteorological
Services and Supporting Research (OFCM)
6010 Executive Blvd, Suite 900
Rockville, MD 20852
Voice: 301-443-8704

For more information about the GRIB format, contact:

U.S. Department of Commerce/National Oceanic and Atmospheric
Administration (NOAA)
National Meteorological Center
Attn: Dr. John D. Stackpole
Chief, Production Management Branch, Automation Division
WINMC42, Room 307, WWB
5200 Auth Road
Camp Springs, MD 20746
Voice: 301-763-8115
FAX: 301-763-8381
Email: [email protected]


This page is taken from the Encyclopedia of Graphics File Formats and is licensed by O'Reilly under the Creative Common/Attribution license.

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