grib2.h(3)

📦

version 2.3.0 · 2 versions

2.3.0 · ubuntu resolute, ubuntu stonking (latest)
2.1.0 · debian trixie, ubuntu questing

okay so bestie, you just opened grib2.h(3) from the Library Functions Manual and honestly? iconic. this is the header file page for the NCEPLIBS-g2c library, and it's a big one, so we're doing this in parts. grab a snack 🍓

✨ NAME ✨

grib2.h — the header file for the NCEPLIBS-g2c library. that's the whole vibe. 💅

🌈 SYNOPSIS 🌈

before literally anything else, you pull in these bad boys right here:

#include <stdint.h>
#include <stdio.h>
#include <string.h>
#include <sys/types.h>

🦋 Data Structures 🦋

struct gribfield — the struct for a GRIB2 field. the whole field. everything about it. she contains multitudes. 💖

✨ Macros ✨

okay this is the long part, and no, we are not skipping any of them, because every single one matters. buckle up 🫶

G2_ADD_MSG_COMPLETE = -2 — GRIB message already complete. it's done, girl, stop adding to it 💀
G2_ADD_MSG_INIT = -1 — GRIB message was not initialized — you gotta call g2_create() first.
G2_ADDFIELD_BAD_BITMAP = -8 — in g2_addfield() there's no bitmap in the GRIB message.
G2_ADDFIELD_BAD_DRT = -7 — in g2_addfield() there's an unsupported Data Representationi Template. (yes that's the spelling, we don't fix it, we respect it 🎀)
G2_ADDFIELD_BAD_GDS = -6 — in g2_addfield() section 3 (GDS) was not previously defined in the message.
G2_ADDFIELD_BAD_GDT = -9 — in g2_addfield() you need a GDT of one of 5.50 through 5.53 when using DRT 5.51.
G2_ADDFIELD_BAD_PDT = -5 — in g2_addfield() it could not find the requested Product Definition Template.
G2_ADDFIELD_ERR = -10 — in g2_addfield() there was an error packing the data field. 😭
G2_ADDGRID_BAD_GDT = -5 — in g2_addgrid() it could not find the requested Grid Definition Template.
G2_AEC_ENABLED = 1 — decoding/encoding AEC/CCSDS is enabled. slay.
G2_BAD_SEC = -4 — the previous Section was unexpected. rude, honestly.
G2_BAD_SEC_COUNTS = -3 — the sum of Section byte counts doesn't add to the total byte count. math said no 🧚
G2_CREATE_GRIB_VERSION = -1 — wrong GRIB version for g2_create(), it must be 2.
G2_GETFLD_BAD_END = 7 — g2_getfld() didn't find 7777"atendofmessage.
G2_GETFLD_BAD_SEC1 = 15 — error in g2_getfld() unpacking section 1.
G2_GETFLD_BAD_SEC2 = 16 — error in g2_getfld() unpacking section 2.
G2_GETFLD_BAD_SEC3 = 10 — error in g2_getfld() unpacking section 3.
G2_GETFLD_BAD_SEC4 = 11 — error in g2_getfld() unpacking section 4.
G2_GETFLD_BAD_SEC5 = 12 — error in g2_getfld() unpacking section 5.
G2_GETFLD_BAD_SEC6 = 13 — error in g2_getfld() unpacking section 6.
G2_GETFLD_BAD_SEC7 = 14 — error in g2_getfld() unpacking section 7.
G2_GETFLD_GRIB_VERSION = 2 — wrong GRIB version for g2_getfld(), it must be 2.
G2_GETFLD_INVAL = 3 — g2_getfld() data field request number was not positive.
G2_GETFLD_INVAL_SEC = 8 — g2_getfld() encountered an unrecognized section.
G2_GETFLD_NO_BITMAP = 17 — in g2_getfld() a previous bitmap was specified, yet none exists.
G2_GETFLD_NO_DRT = 9 — in g2_getfld(), the Data Representation Template is not implemented.
G2_GETFLD_NO_GRIB = 1 — g2_getfld() can't find the beginning characters GRIB".
G2_GETFLD_WRONG_END = 4 — g2_info() found 7777"notwhereexpected.
G2_GETFLD_WRONG_NFLDS = 6 — in g2_getfld() the message did not contain the requested number of data fields.
G2_GRIBEND_MSG_INIT = -1 — in g2_gribend() the GRIB message was not initialized — you gotta call g2_create() first.
G2_INFO_BAD_END = 5 — g2_info() didn't find 7777"atendofmessage.
G2_INFO_GRIB_VERSION = 2 — wrong GRIB version for g2_info(), it must be 2.
G2_INFO_INVAL_SEC = 6 — g2_info() found an invalid section number.
G2_INFO_NO_GRIB = 1 — g2_info() can't find the beginning characters GRIB".
G2_INFO_NO_SEC1 = 3 — g2_info() can't find section 1.
G2_INFO_WRONG_END = 4 — g2_info() found 7777"notwhereexpected.
G2_JASPER_DECODE = -3 — in dec_jpeg2000() there was an error decoding the image with jasper.
G2_JASPER_DECODE_COLOR = -5 — in dec_jpeg2000() the decoded image had multiple color components.
G2_JASPER_ENCODE = -3 — in enc_jpeg2000() there was an error encoding the image with jasper.
G2_JASPER_INIT = -2 — in enc_jpeg2000()/dec_jpeg2000() there was an error initializing the jasper library.
G2_JPCUNPACK_MEM = 1 — in jpcunpack() or another unpack function: out of memory. 💀
G2_JPEG2000_ENABLED = 1 — decoding/encoding JPEG2000 is enabled. ate.
G2_NO_ERROR = 0 — the function succeeded. we love to see it 👑
G2_PNG_ENABLED = 1 — decoding/encoding PNG is enabled.
G2_SPECUNPACK_TYPE = -3 — in specunpack() it can't handle 64 or 128 bit floats.
G2_UNPACK3_BAD_GDT = 5 — in g2_unpack3(), undefined Grid Definition Template.
G2_UNPACK4_BAD_PDT = 5 — in g2_unpack4(), undefined Product Definition Template.
G2_UNPACK5_BAD_DRT = 7 — in g2_unpack5(), undefined Data Representation Template.
G2_UNPACK6_BAD_BITMAP = 4 — in g2_unpack6(), unrecognized pre-defined bit-map.
G2_UNPACK7_BAD_DRT = 4 — in g2_unpack7(), unrecognized Data Representation Template.
G2_UNPACK7_CORRUPT_SEC = 7 — in g2_unpack7(), corrupt section 7.
G2_UNPACK7_WRONG_GDT = 5 — in g2_unpack7(), you need one of GDT 3.50 through 3.53 to decode DRT 5.51.
G2_UNPACK_BAD_SEC = 2 — bad section number in the unpacking function.
G2_UNPACK_NO_MEM = 6 — error allocating memory in the unpack function.
G2C_AEC_DRS_TEMPLATE_LEN = 8 — length of the idrstmpl array for AEC packing.
G2C_BYTE = 1 — signed 1 byte integer.
G2C_CHAR = 2 — ISO/ASCII character.
G2C_CLOBBER = 0x0000 — destroy the existing file. bestie. that file is GONE 😭
G2C_DOUBLE = 6 — double precision floating point number.
G2C_EAEC = (-74) — error encoding/decoding AEC data.
G2C_EBADEND = (-65) — end of message in the wrong place.
G2C_EBADID = (-55) — bad ID.
G2C_EBADSECTION = (-66) — invalid section number.
G2C_EBADTEMPLATE = (-70) — template problem.
G2C_EBADTYPE = (-73) — type not found.
G2C_ECSV = (-75) — CSV error.
G2C_EFILE = (-54) — file I/O error.
G2C_EINVAL = (-53) — invalid input.
G2C_EJPEG = (-67) — error encoding/decoding JPEG data.
G2C_EMSG = (-58) — error decoding GRIB message.
G2C_EMSGCOMPLETE = (-51) — GRIB message already complete.
G2C_ENAMETOOLONG = (-52) — name too long.
G2C_ENOEND = (-64) — cannot find the end of the GRIB message.
G2C_ENOMEM = (-57) — out of memory.
G2C_ENOMSG = (-59) — no GRIB message found.
G2C_ENOPARAM = (-71) — parameter not found.
G2C_ENOPRODUCT = (-72) — product not found.
G2C_ENOSECTION = (-63) — cannot find section.
G2C_ENOTEMPLATE = (-69) — template not found.
G2C_ENOTFOUND = (-61) — table or entry not found.
G2C_ENOTGRIB = (-50) — GRIB header not found.
G2C_ENOTGRIB2 = (-62) — not GRIB 2.
G2C_EPNG = (-68) — error encoding/decoding PNG data.
G2C_ERROR = 1 — general error code, returned for some test errors.
G2C_ETOOMANYFILES = (-56) — trying to open too many files.
G2C_EXML = (-60) — XML error.
G2C_FLOAT = 5 — single precision floating point number.
G2C_INT = 4 — signed 4 byte integer.
G2C_INT64 = 10 — signed 8-byte int.
G2C_JASPER_MAX_MEM — maximum size for the Jasper memory buffer. (no value attached, she's just vibes ✨)
G2C_JPEG_DRS_TEMPLATE_LEN = 7 — length of the idrstmpl array for JPEG packing.
G2C_LARGE_FILE_INDEX = 0x0008 — create a large file index.
G2C_MAX_DRS_TEMPLATE = 11 — maximum number of DRS templates.
G2C_MAX_DRS_TEMPLATE_MAPLEN = 18 — maximum DRS template map length.
G2C_MAX_FILES = 3 — maximum number of open files.
G2C_MAX_GDS_TEMPLATE = 38 — maximum number of grid templates.
G2C_MAX_GDS_TEMPLATE_MAPLEN = 28 — maximum grid template map length.
G2C_MAX_GRIB_CODE_LEN = 20 — maximum length of code.
G2C_MAX_GRIB_DESC_LEN = 512 — maximum length of code description.
G2C_MAX_GRIB_LEVEL_DESC_LEN = 40 — maximum length of level description.
G2C_MAX_GRIB_STATUS_LEN = 40 — maximum length of code status.
G2C_MAX_GRIB_TITLE_LEN = 200 — maximum length of code table title.
G2C_MAX_NAME = 1024 — maximum length of a name.
G2C_MAX_NOAA_ABBREV_LEN = 11 — maximum length of a NOAA abbreviation of a parameter.
G2C_MAX_NOAA_PARAM_LINE_LEN = 120 — maximum length of a line in the NOAA abbreviation CSV file.
G2C_MAX_NOAA_PARAMS = 2000 — maximum number of known parameters with NOAA abbreviations.
G2C_MAX_NUM_SECTIONS = 1024 — maximum number of sections that can be handled in one message.
G2C_MAX_PDS_TEMPLATE = 102 — maximum number of PDS templates.
G2C_MAX_PDS_TEMPLATE_MAPLEN = 50 — maximum template map length.
G2C_NOCLOBBER = 0x0004 — don't destroy the existing file. (the respectful option 🫶)
G2C_NOERROR = 0 — no error.
G2C_NOWRITE = 0x0000 — set read-only access for g2c_open().
G2C_PNG_DRS_TEMPLATE_LEN = 5 — length of the idrstmpl array for PNG packing.
G2C_PNG_HEIGHT_MAX = 100000 — maximum height of a PNG grid.
G2C_PNG_WIDTH_MAX = 100000000 — maximum width of a PNG grid.
G2C_SECTION0_ARRAY_LEN = 3 — length of the section 0 array.
G2C_SECTION0_BYTES = 16 — number of bytes in section 0.
G2C_SECTION0_LEN = 3 — length of the section 0 array.
G2C_SECTION1_ARRAY_LEN = 13 — length of the section 1 array.
G2C_SECTION1_BYTES = 21 — number of bytes in section 1 (not including reserved, optional data at the end of the section).
G2C_SECTION1_LEN = 13 — length of the section 1 array.
G2C_SHORT = 3 — signed 2 byte integer.
G2C_UBYTE = 7 — unsigned 1 byte int.
G2C_UINT = 9 — unsigned 4-byte int.
G2C_UINT64 = 11 — unsigned 8-byte int.
G2C_USHORT = 8 — unsigned 2-byte int.
G2C_VERSION = '2.3.0' — current version of the NCEPLIBS-g2c library. 💜
G2C_WRITE = 0x0001 — set read-write access for g2c_open().

🎀 Typedefs 🎀

typedef float g2float — float type.
typedef int64_t g2int — long integer type.
typedef uint64_t g2intu — unsigned long integer type.
typedef struct gribfield gribfield — the struct for a GRIB field. her again, still iconic 💖

part 1 done, bestie — there's more coming, don't go anywhere 🦋

🦋 Functions 🦋

okay bestie, this is the entire function roster — every signature, every one-liner, zero skips, no crumbs left behind 🍓 grab a snack, we're doing all of them.

g2int g2_addfield (unsigned char *cgrib, g2int ipdsnum, g2int *ipdstmpl, float *coordlist, g2int numcoord, g2int idrsnum, g2int *idrstmpl, float *fld, g2int ngrdpts, g2int ibmap, g2int *bmap) — packs sections 4 through 7 and adds them onto a GRIB2 message. section stacking, but make it cute 🎀
g2int g2_addgrid (unsigned char *cgrib, g2int *igds, g2int *igdstmpl, g2int *ideflist, g2int idefnum) — packs a Grid Definition Section (Section 3) and adds it onto a GRIB2 message. grid goes in, grid goes on 📐
g2int g2_addlocal (unsigned char *cgrib, unsigned char *csec2, g2int lcsec2) — adds a Local Use Section (Section 2) onto a GRIB2 message. your lil local secret, tucked in 🙈
g2int g2_create (unsigned char *cgrib, g2int *listsec0, g2int *listsec1) — initializes a brand new GRIB2 message and packs GRIB2 Section 0 (Indicator Section) and Section 1 (Identification Section). birth of a message, main character energy ✨
void g2_free (gribfield *gfld) — frees the memory that was allocated for struct gribfield. cleanup era 🧹
g2int g2_getfld (unsigned char *cgrib, g2int ifldnum, g2int unpack, g2int expand, gribfield **gfld) — hands you back all the metadata, the template values, the bit-map (if there is one), and the unpacked data for a data field. the full reveal 💖
g2int g2_gribend (unsigned char *cgrib) — finalizes a GRIB2 message once all the grids and fields have been added. closing the chapter, periodt 🔥
g2int g2_info (unsigned char *cgrib, g2int *listsec0, g2int *listsec1, g2int *numfields, g2int *numlocal) — searches through a GRIB2 message and returns how many gridded fields it found in there, plus the number (and the maximum size) of Local Use Sections. receipts, but for message structure 🧾
g2int g2_unpack1 (unsigned char *cgrib, g2int *iofst, g2int **ids, g2int *idslen) — unpacks Section 1 — the Identification Section — of a GRIB2 message. 🪪
g2int g2_unpack2 (unsigned char *cgrib, g2int *iofst, g2int *lencsec2, unsigned char **csec2) — unpacks Section 2 (the Local Use Section) of a GRIB2 message. 🎁
g2int g2_unpack3 (unsigned char *cgrib, g2int *iofst, g2int **igds, g2int **igdstmpl, g2int *mapgridlen, g2int **ideflist, g2int *idefnum) — unpacks Section 3 (the Grid Definition Section) of a GRIB2 message. 🗺️
g2int g2_unpack4 (unsigned char *cgrib, g2int *iofst, g2int *ipdsnum, g2int **ipdstmpl, g2int *mappdslen, float **coordlist, g2int *numcoord) — unpacks Section 4 (the Product Definition Section) of a GRIB2 message. 📦
g2int g2_unpack5 (unsigned char *cgrib, g2int *iofst, g2int *ndpts, g2int *idrsnum, g2int **idrstmpl, g2int *mapdrslen) — unpacks Section 5 (the Data Representation Section) of a GRIB2 message. 🧬
g2int g2_unpack6 (unsigned char *cgrib, g2int *iofst, g2int ngpts, g2int *ibmap, g2int **bmap) — unpacks Section 6 (the Bit-Map Section) of a GRIB2 message. little dots, big meaning ⚫
g2int g2_unpack7 (unsigned char *cgrib, g2int *iofst, g2int igdsnum, g2int *igdstmpl, g2int idrsnum, g2int *idrstmpl, g2int ndpts, float **fld) — this subroutine unpacks Section 7 (the Data Section) of a GRIB2 message. the actual numbers, bestie 🌈
int g2c_aecpackd (double *fld, size_t width, size_t height, int *idrstmpl, unsigned char *cpack, size_t *lcpack) — packs up a double array into an AEC code stream. squish it down, doubles 🗜️
int g2c_aecpackf (float *fld, size_t width, size_t height, int *idrstmpl, unsigned char *cpack, size_t *lcpack) — packs up a float array into an AEC code stream. 🗜️
int g2c_aecunpackd (unsigned char *cpack, size_t len, int *idrstmpl, size_t ndpts, double *fld) — unpacks AEC compressed data into an array of doubles, using the info from GRIB2 Data Representation Template 5.42. 🪄
int g2c_aecunpackf (unsigned char *cpack, size_t len, int *idrstmpl, size_t ndpts, float *fld) — unpacks AEC compressed data into an array of floats, using the info from GRIB2 Data Representation Template 5.42. 🪄
int g2c_close (int g2cid) — closes a GRIB2 file and frees the resources. bye babe, take your memory with you 👋
int g2c_compare (int g2cid1, int g2cid2) — compares the metadata of two open GRIB2 files. vibe check, but for metadata ⚖️
int g2c_csv_init () — initializes tables from CodeFlag.txt". 📊
int g2c_dec_aec (unsigned char *cpack, int len, int nbits, int flags, int block_size, int rsi, unsigned char *cfld, int cfldlen) — decodes an AEC code stream specified in the CCSDS 121.0-B-3 Blue Book. 📘
int g2c_dec_jpeg2000 (char *injpc, size_t bufsize, int *outfld) — decodes a JPEG2000 code stream specified in the JPEG2000 Part-1 standard (i.e., ISO/IEC 15444-1) using JasPer Software. 🖼️
int g2c_dec_png (unsigned char *pngbuf, int *width, int *height, unsigned char *cout) — decodes PNG. 🌷
int g2c_degrib2 (int g2cid, const char *fileout) — writes a summary file like the degrib2 utility does. 📝
int g2c_enc_aec (unsigned char *data, int ctemplen, int nbits, int flags, int block_size, int rsi, unsigned char *aecbuf, int *aecbuflen) — encodes data into an AEC code stream specified in the CCSDS 121.0-B-3 Blue Book. 📘
int g2c_enc_jpeg2000 (unsigned char *cin, int width, int height, int nbits, int ltype, int ratio, int retry, char *outjpc, size_t jpclen) — encodes a grayscale image into a JPEG2000 code stream specified in the JPEG2000 Part-1 standard (i.e., ISO/IEC 15444-1) using JasPer Software. 🖼️
int g2c_enc_png (unsigned char *data, int width, int height, int nbits, unsigned char *pngbuf) — encodes PNG. 🌷
int g2c_find_desc (char *title, int code, char *desc) — given a table title and an integer code, finds you a description. 🔍
int g2c_find_desc_str (char *title, char *code, char *desc) — given a table title and a code, finds you a description. 🔍
int g2c_find_msg2 (int g2cid, size_t skip_bytes, size_t max_bytes, size_t *bytes_to_msg, size_t *bytes_in_msg) — searches a file for the next GRIB1 or GRIB2 message. 🕵️
void g2c_free_tables () — frees the table memory. tables cleared, no crumbs 🧹
void g2c_gbit_int (unsigned char *in, int *iout, int iskip, int nbits) — extracts arbitrary size values out of a packed bit string, right justifying each value in the unpacked iout array. 🧷
int g2c_gbits_int (unsigned char *in, int *iout, int iskip, int nbits, int nskip, int n) — extracts arbitrary size values out of a packed bit string, right justifying each value in the unpacked iout array. same energy, more args 🧷
int g2c_get_drs_template (int drs_template_num, int *maplen, int *map, int *needext) — gets DRS template information. 📋
int g2c_get_gdt_len (int grid_template_num, int *maplen) — gets the initial length (number of entries) in the static part of a Grid Definition Template. 📏
int g2c_get_grid_template (int grid_template_num, int *maplen, int *map, int *needext) — gets grid template information. 📋
int g2c_get_grid_template_extension (int grid_template_num, int *g2c_template, int *extlen, int *ext) — gets grid template extension information. 📋
int g2c_get_msg (int g2cid, size_t skip_bytes, size_t max_bytes, size_t *bytes_to_msg, size_t *bytes_in_msg, unsigned char **cbuf) — searches a file for the next GRIB1 or GRIB2 message, and reads it, allocating space in memory to hold that message. find it AND hold it, multi-tasking queen 💅
int g2c_get_pds_template (int pds_template_num, int *maplen, int *map, int *needext) — gets PDS template information. 📋
int g2c_get_pds_template_extension (int pds_template_num, int *g2c_template, int *extlen, int *ext) — gets pds template extension information. 📋
int g2c_get_pdt_len (int pds_template_num, int *maplen) — gets the initial length (number of entries) in the static part of a PDS template. 📏
int g2c_get_prod (int g2cid, int msg_num, int prod_num, int *num_data_points, float *data) — reads the data for a product. 📖
int g2c_inq (int g2cid, int *num_msg) — learns about a GRIB2 file. getting to know u fr fr 🫶
int g2c_inq_dim (int g2cid, int msg_num, int prod_num, int dim_num, size_t *len, char *name, float *val) — learns about one of the dimensions of a GRIB2 product. 📐
int g2c_inq_dim_info (int g2cid, int msg_num, int prod_num, int dim_num, size_t *len, char *name) — learns about one of the dimensions of a GRIB2 product. 📐
int g2c_inq_msg (int g2cid, int msg_num, unsigned char *discipline, int *num_fields, int *num_local, short *center, short *subcenter, unsigned char *master_version, unsigned char *local_version) — learns about a GRIB2 message. 💌
int g2c_inq_msg_time (int g2cid, int msg_num, unsigned char *sig_ref_time, short *year, unsigned char *month, unsigned char *day, unsigned char *hour, unsigned char *minute, unsigned char *second) — learns about the date/time information in a GRIB2 message. ⏰
int g2c_inq_prod (int g2cid, int msg_num, int prod_num, int *pds_template_len, long long int *pds_template, int *gds_template_len, long long int *gds_template, int *drs_template_len, long long int *drs_template) — inquires about a product. all the deets, all three templates 🧐
int g2c_jpcpackd (double *fld, size_t width, size_t height, int *idrstmpl, unsigned char *cpack, size_t *lcpack) — packs up a double array into a JPEG2000 code stream. 🗜️
int g2c_jpcpackf (float *fld, size_t width, size_t height, int *idrstmpl, unsigned char *cpack, size_t *lcpack) — packs up a float array into a JPEG2000 code stream. 🗜️
int g2c_jpcunpackd (unsigned char *cpack, size_t len, int *idrstmpl, size_t ndpts, double *fld) — unpacks JPEG2000 compressed data into an array of doubles, using the info from GRIB2 Data Representation Template 5.40 or 5.40000. 🪄
int g2c_jpcunpackf (unsigned char *cpack, size_t len, int *idrstmpl, size_t ndpts, float *fld) — unpacks JPEG2000 compressed data into an array of floats, using the info from GRIB2 Data Representation Template 5.40 or 5.40000. 🪄
int g2c_log_file (int g2cid) — prints a summary of the contents of an open GRIB2 file. 🪵
int g2c_open (const char *path, int mode, int *g2cid) — opens an existing GRIB2 file. come on in bestie 🚪
int g2c_open_index (const char *data_file, const char *index_file, int mode, int *g2cid) — opens a GRIB2 file with the help of an index file. 🗂️
int g2c_open_index1 (const char *index_file) — opens a GRIB1 index file and reads the contents. 🗂️
int g2c_param_abbrev (int g2disc, int g2cat, int g2num, char *abbrev) — gets the NOAA abbreviation for a GRIB2 parameter. 🏷️
int g2c_param_all (int param_idx, int *g1ver, int *g1val, int *g2disc, int *g2cat, int *g2num, char *abbdrev) — returns all the information about a parameter. the whole lore drop 📚
int g2c_param_g1tog2 (int g1val, int g1ver, int *g2disc, int *g2cat, int *g2num) — translates a GRIB1 parameter to a GRIB2 parameter. 🔄
int g2c_param_g2tog1 (int g2disc, int g2cat, int g2num, int *g1val, int *g1ver) — translates a GRIB2 parameter to a GRIB1 parameter. 🔄
int g2c_pngpackd (double *fld, size_t width, size_t height, int *idrstmpl, unsigned char *cpack, int *lcpack) — this subroutine packs up a double data field into PNG image format. 🎨
int g2c_pngpackf (float *fld, size_t width, size_t height, int *idrstmpl, unsigned char *cpack, int *lcpack) — …

Okay bestie, we're still in the function lineup, so let's keep it moving 💅

This subroutine packs up a float data field into PNG image format.

int g2c_pngunpackd (unsigned char *cpack, size_t len, int *idrstmpl,
    size_t ndpts, double *fld)

This one unpacks a data field that got packed into PNG image format, using the info from the GRIB2 Data Representation Template 5.41 or 5.40010.

int g2c_pngunpackf (unsigned char *cpack, size_t len, int *idrstmpl,
    size_t ndpts, float *fld)

Same energy, also unpacks a data field packed into PNG image format using info from GRIB2 Data Representation Template 5.41 or 5.40010.

int g2c_seekmsg (int g2cid, size_t skip, size_t *offset, size_t *msglen)

Search a file for the next GRIB2 Message. it's giving "where's the message, bestie" 🔍

int g2c_set_log_level (int new_level)

Use this to set the global log level. yes she has a volume knob, and yes you can turn her up 🔊

const char * g2c_strerror (int g2cerr)

Hand it an error code, she hands you back an error message. emotional support for your errno 💖

int g2c_unpack7 (unsigned char *cgrib, int igdsnum, int gds_tmpl_len,
    long long int *gdstmpl, int idrsnum, int drs_tmpl_len, long long int
    *drstmpl, int ndpts, float *fld)

This subroutine unpacks Section 7 (Data Section) of a GRIB2 message. the main character section fr fr ✨

int g2c_write_index (int g2cid, int mode, const char *index_file)

Create an index file from a GRIB2 file, just like the ones the grb2index utility makes. matching sets, iconic 👑

void seekgb (FILE *lugb, g2int iseek, g2int mseek, g2int *lskip, g2int
    *lgrib)

Search a file for the next GRIB Message.

💫 Detailed Description 💫

Header file for NCEPLIBS-g2c library. that's the whole vibe, she's the blueprint 🎀

📜 Program History Log 📜

2002-10-25 — Gilbert — Initial
2009-01-14 — Vuong — Changed struct template to gtemplate
2021-11-9 — Ed Hartnett — Moved many prototypes to new internal header grib2_int.h.
2022-04-15 — Ed Hartnett — Added error codes related to JPEG.
2022-08-15 — Ed Hartnett — Added compression functions for double.
2023-09-10 — Eric Engle — Added AEC compression.

✍️ Author

Stephen Gilbert

📅 Date

2002-10-25

✍️ Author

Ed Hartnett

📂 Definition in file

grib2.h.

🧬 Data Type Documentation 🧬

🌸 struct gribfield 🌸

Struct for GRIB2 field. the moment, the icon, the legend 💖

Definition at line 45 of file grib2.h.

Data Fields:

g2int * bmap — Integer array holding the decoded bitmap, if ibmap=0 or ibap=254. Otherwise NULL.
float * coord_list — Array holding floating point values meant to document the vertical discretisation associated to model data on hybrid coordinate vertical levels (part of Section 4).
g2int discipline — Message Discipline (see Table 0.0).
g2int expanded — Logical value saying whether the data field was expanded to the grid in the case where a bit-map is present. If true, the data points in fld match the grid points and zeros were inserted at grid points where data was bit-mapped out. If false, the data values in ld were not expanded to the grid and are just a consecutive array of data points corresponding to each value of "1" in bmap.
float * fld — Array of ndpts unpacked data points.
g2int griddef — Source of grid definition (see Table 3.0).
- 0 Specified in Table 3.1.
- 1 Predetermined grid Defined by originating centre.
g2int ibmap — Bitmap indicator (see Table 6.0).
- 0 bitmap applies and is included in Section 6.
- 1-253 = Predefined bitmap applies
- 254 = Previously defined bitmap applies to this field
- 255 = Bit map does not apply to this product.
g2int idrtlen — Number of elements in idrtmpl.
g2int * idrtmpl — Contains the data values for the Data Representation Template specified by idrtnum.
g2int idrtnum — Data Representation Template Number (see Table 5.0).
g2int * idsect — Contains the entries in the Identification Section (Section 1).
- idsect[0] Identification of originating Centre (see Table 0). 7 is the identification for the US National Weather Service.
- idsect[1] Identification of originating Sub-centre. (See Table C).
- idsect[2] GRIB Master Tables Version Number (see Table 1.0).
  - 0 Experimental
  - 1 Initial operational version number
- idsect[3] GRIB Local Tables Version Number (see Table 1.1).
  - 0 Local tables not used
  - 1-254 Number of local tables version used
- idsect[4] Significance of Reference Time (See Table 1.2).
  - 0 Analysis
  - 1 Start of forecast
  - 2 Verifying time of forecast
  - 3 Observation time
- idsect[5] Year (4 digits)
- idsect[6] Month
- idsect[7) Day
- idsect[8] Hour
- idsect[9] Minute
- idsect[10] Second
- idsect[11] Production status of processed data (see Table 1.3).
  - 0 Operational products
  - 1 Operational test products
  - 2 Research products
  - 3 Re-analysis products
- idsect[12] Type of processed data (see Table 1.4).
  - 0 Analysis products
  - 1 Forecast products
  - 2 Analysis and forecast products
  - 3 Control forecast products
  - 4 Perturbed forecast products
  - 5 Control and perturbed forecast products
  - 6 Processed satellite observations
  - 7 Processed radar observations
g2int idsectlen — Number of elements in idsect.
g2int ifldnum — Field number within GRIB message.
g2int igdtlen — Number of elements in igdtmpl - i.e. number of entries in Grid Defintion Template.
g2int * igdtmpl — Contains the data values for the Grid Definition Template specified by igdtnum.
g2int igdtnum — Grid Definition Template Number (See Table 3.1).
g2int interp_opt — Interpretation of list for optional points definition. (See Table 3.11).
g2int ipdtlen — Number of elements in ipdtmpl - i.e. number of entries in Product Defintion Template.
g2int * ipdtmpl — Contains the data values for the Product Definition Template specified by ipdtnum.
g2int ipdtnum — Product Definition Template Number (see Table 4.0).
g2int * list_opt — (Used if numoct_opt .ne. 0) This array contains the number of grid points contained in each row (or column) (part of Section 3). NULL if numoct_opt = 0.
unsigned char * local — Pointer to character array containing contents of Local Section 2, if included.
g2int locallen — Length of array local.
g2int ndpts — Number of data points unpacked and returned.
g2int ngrdpts — Number of grid points in the defined grid.
g2int num_coord — Number of values in array coord_list.
g2int num_opt — (Used if numoct_opt .ne. 0) The number of entries in array ideflist - i.e. number of rows (or columns) for which optional grid points are defined. This value is set to zero, if numoct_opt=0.
g2int numoct_opt — Number of octets needed for each additional grid points definition. Used to define number of points in each row (or column) for non-regular grids. = 0, if using regular grid.
g2int unpacked — Logical value saying whether the bitmap and data values were unpacked. If false, bmap and fld pointers are NULL.
g2int version — GRIB edition number (2).

🎀 Macro Definition Documentation 🎀

🔥 `G2_ADD_MSG_COMPLETE` 🔥

#define G2_ADD_MSG_COMPLETE   -2

GRIB message already complete. Cannot add new section. sorry babe, the message said goodbye 💀

Definition at line 473 of file grib2.h.

Referenced by g2_addfield(), g2_addgrid(), g2_addlocal(), and g2_gribend().

🔥 `G2_ADD_MSG_INIT` 🔥

#define G2_ADD_MSG_INIT   -1

GRIB message was not initialized - call g2_create() first. you forgot to start it bestie, go start it 😭

Definition at line 472 of file grib2.h.

Referenced by g2_addfield(), g2_addgrid(), g2_addlocal(), and g2_gribend().