SECTION 0 Indicator section

SECTION 1 Product definition section

SECTION 2 (Grid description section)

SECTION 3 (Bit-map section)

SECTION 4 Binary data section

SECTION 5 7777


(1) GRIB is the name of the binary code for the exchange of processed data.

(2) The GRIB coded analysis or forecast consists of a continuous bit-stream made of a sequence of octets (1 octet = 8 bits).

(3) The octets of a GRIB message are grouped in sections:

Section number Name Contents
0 Indicator section "GRIB", length of message, GRIB edition number
1 Product definition section Length of section, identification of the coded analysis or forecast
2 Grid description section (optional) Length of section, grid geometry, as necessary
3 Bit-map section (optional) Length of section; the bit per grid point, placed in suitable sequence, indicates omission (bit 0) or inclusion (bit 1) of data at respective points
4 Binary data section Length of section and data values
5 End section 7777

(4) Although the Grid description section is indicated as optional, it is strongly urged that it be included in all GRIB messages.

(5) It will be noted that the GRIB code is not suitable for visual data recognition without computer interpretation.

(6) The representation of data by means of series of bits is independent of any particular machine representation.

(7) Message and section lengths are expressed in octets. Section 0 has a fixed length of 8 octets; Section 5 has a fixed length of 4 octets. Sections 1, 2, 3 and 4 have a variable length which is included in the first three octets of each section.

(8) In the GRIB message, the bit length of "International Alphabet No. 5" is regarded as 8-bit, adding one bit "0" to the 7-bit of IA5 as the most significant bit.