getgi.f File Reference

Read a grib index file and return its contents. More...

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Functions/Subroutines
subroutine	getgi (lugi, mnum, mbuf, cbuf, nlen, nnum, iret)
	Read a grib index file and return its contents.

Detailed Description

Read a grib index file and return its contents.

Author

Mark Iredell

Date

1995-10-31

Definition in file getgi.f.

Function/Subroutine Documentation

getgi()

subroutine getgi	(		lugi,
			mnum,
			mbuf,
		character, dimension(mbuf)	cbuf,
			nlen,
			nnum,
			iret
	)

Read a grib index file and return its contents.

Version 1 of the index file has the following format: 81-byte s.lord header with 'gb1ix1' in columns 42-47 followed by 81-byte header with number of bytes to skip before index records, number of bytes in each index record, number of index records, and grib file basename written in format ('ix1form:',3i10,2x,a40). Each following index record corresponds to a grib message and has the internal format:

• byte 001-004: bytes to skip in data file before grib message.
• byte 005-008: bytes to skip in message before pds.
• byte 009-012: bytes to skip in message before gds (0 if no gds).
• byte 013-016: bytes to skip in message before bms (0 if no bms).
• byte 017-020: bytes to skip in message before bds.
• byte 021-024: bytes total in the message.
• byte 025-025: grib version number.
• byte 026-053: product definition section (pds).
• byte 054-095: grid definition section (gds) (or nulls).
• byte 096-101: first part of the bit map section (bms) (or nulls).
• byte 102-112: first part of the binary data section (bds).
• byte 113-172: (optional) bytes 41-100 of the pds.
• byte 173-184: (optional) bytes 29-40 of the pds.
• byte 185-320: (optional) bytes 43-178 of the gds.

Program history log:

• Mark Iredell 1995-10-31
• Mark Iredell 1996-10-31 Augmented optional definitions to byte 320.

Parameters

[in]	lugi	integer unit of the unblocked grib index file.
[in]	mnum	integer number of index records to skip (usually 0).
[in]	mbuf	integer length of cbuf in bytes.
[out]	cbuf	character*1 (mbuf) buffer to receive index data.
[out]	nlen	integer length of each index record in bytes.
[out]	nnum	integer number of index records.
[out]	iret	integer return code. 0: all ok. 1: cbuf too small to hold index buffer. 2: error reading index file buffer. 3: error reading index file header.

Note

Subprogram can be called from a multiprocessing environment. Do not engage the same logical unit from more than one processor.

Author

Mark Iredell

Date

1995-10-31

Definition at line 49 of file getgi.f.