Description
This example shows: how to read attributes of keys in BUFR messages.
Source code
bufr_attributes.f90
! ! Copyright 2005- ECMWF. ! ! This software is licensed under the terms of the Apache Licence Version 2.0 ! which can be obtained at http://www.apache.org/licenses/LICENSE-2.0. ! ! In applying this licence, ECMWF does not waive the privileges and immunities granted to it by ! virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction. ! ! ! FORTRAN 90 Implementation: bufr_attributes ! ! Description: how to read attributes of keys in BUFR messages. ! ! program bufr_attributes use eccodes implicit none integer :: ifile integer :: iret integer :: ibufr integer :: count=0 integer(kind=4) :: iVal,conf real(kind=8) :: t2m character(len=32) :: units, confUnits call codes_open_file(ifile,'../../data/bufr/syno_multi.bufr','r') ! the first bufr message is loaded from file ! ibufr is the bufr id to be used in subsequent calls call codes_bufr_new_from_file(ifile,ibufr,iret) do while (iret/=CODES_END_OF_FILE) ! Get and print some keys form the BUFR header write(*,*) 'message: ',count ! We need to instruct ecCodes to expand all the descriptors ! i.e. unpack the data values call codes_set(ibufr,"unpack",1); ! ---------------------------------------------------------------- ! We will read the value and all the attributes available for ! the 2m temperature. ! ---------------------------------------------------------------- ! Get the element's value as as real call codes_get(ibufr,'airTemperatureAt2M',t2m); write(*,*) ' airTemperatureAt2M:',t2m ! Get the element's code (see BUFR code table B) call codes_get(ibufr,'airTemperatureAt2M->code',iVal); write(*,*) ' airTemperatureAt2M->code:',iVal ! Get the element's units (see BUFR code table B) call codes_get(ibufr,'airTemperatureAt2M->units',units) write(*,*) ' airTemperatureAt2M->units:',units ! Get the element's scale (see BUFR code table B) call codes_get(ibufr,'airTemperatureAt2M->scale',iVal); write(*,*) ' airTemperatureAt2M->code:',iVal ! Get the element's reference (see BUFR code table B) call codes_get(ibufr,'airTemperatureAt2M->reference',iVal); write(*,*) ' airTemperatureAt2M->reference:',iVal ! Get the element's width (see BUFR code table B) call codes_get(ibufr,'airTemperatureAt2M->width',iVal); write(*,*) ' airTemperatureAt2M->width:',iVal ! ------------------------------------------------------------------- ! The 2m temperature data element in this message has an associated ! field: percentConfidence. Its value and attributes can be accessed ! in a similar manner as was shown above for 2m temperature. ! ------------------------------------------------------------------- ! Get the element's value as as real call codes_get(ibufr,'airTemperatureAt2M->percentConfidence',conf); write(*,*) ' airTemperatureAt2M->percentConfidence:', conf ! Get the element's code (see BUFR code table B) call codes_get(ibufr,'airTemperatureAt2M->percentConfidence->code',iVal); write(*,*) ' airTemperatureAt2M->percentConfidence->code:',iVal ! Get the element's units (see BUFR code table B) call codes_get(ibufr,'airTemperatureAt2M->percentConfidence->units',confUnits) write(*,*) ' airTemperatureAt2M->percentConfidence->units:',confUnits ! Get the element's scale (see BUFR code table B) call codes_get(ibufr,'airTemperatureAt2M->percentConfidence->scale',iVal); write(*,*) ' airTemperatureAt2M->percentConfidence->code:',iVal ! Get the element's reference (see BUFR code table B) call codes_get(ibufr,'airTemperatureAt2M->percentConfidence->reference',iVal); write(*,*) ' airTemperatureAt2M->percentConfidence->reference:',iVal ! Get the element's width (see BUFR code table B) call codes_get(ibufr,'airTemperatureAt2M->percentConfidence->width',iVal); write(*,*) ' airTemperatureAt2M->percentConfidence->width:',iVal ! Release the bufr message call codes_release(ibufr) ! Load the next bufr message call codes_bufr_new_from_file(ifile,ibufr,iret) count=count+1 end do ! Close file call codes_close_file(ifile) end program bufr_attributes
bufr_attributes.py
# Copyright 2005- ECMWF. # # This software is licensed under the terms of the Apache Licence Version 2.0 # which can be obtained at http://www.apache.org/licenses/LICENSE-2.0. # # In applying this licence, ECMWF does not waive the privileges and immunities # granted to it by virtue of its status as an intergovernmental organisation # nor does it submit to any jurisdiction. # # Python implementation: bufr_attributes # # Description: how to read attributes of keys in BUFR messages. # # import sys import traceback from eccodes import * INPUT = '../../data/bufr/syno_multi.bufr' VERBOSE = 1 # verbose error reporting def example(): # open bufr file f = open(INPUT, 'rb') cnt = 0 # define the attributes to be printed (see BUFR code table B) attrs = [ 'code', 'units', 'scale', 'reference', 'width' ] # loop for the messages in the file while 1: # get handle for message bufr = codes_bufr_new_from_file(f) if bufr is None: break print("message: %s" % cnt) # we need to instruct ecCodes to expand all the descriptors # i.e. unpack the data values codes_set(bufr, 'unpack', 1) # -------------------------------------------------------------- # We will read the value and all the attributes available for # the 2m temperature. # -------------------------------------------------------------- # get the value key = 'airTemperatureAt2M' try: print(' %s: %s' % (key, codes_get(bufr, key))) except CodesInternalError as err: print('Error with key="%s" : %s' % (key, err.msg)) # print the values of the attributes of the key. Attributes themselves # are keys as well. Their name is constructed like: # keyname->attributename for attr in attrs: key = 'airTemperatureAt2M' + "->" + attr try: print(' %s: %s' % (key, codes_get(bufr, key))) except CodesInternalError as err: print('Error with key="%s" : %s' % (key, err.msg)) # ------------------------------------------------------------------ # The 2m temperature data element in this message has an associated # field: percentConfidence. Its value and attributes can be accessed # in a similar manner as was shown above for 2m temperature. # ------------------------------------------------------------------ # get the value key = 'airTemperatureAt2M->percentConfidence' try: print(' %s: %s' % (key, codes_get(bufr, key))) except CodesInternalError as err: print('Error with key="%s" : %s' % (key, err.msg)) # print the values of the attributes of the key. for attr in attrs: key = 'airTemperatureAt2M->percentConfidence' + "->" + attr try: print(' %s: %s' % (key, codes_get(bufr, key))) except CodesInternalError as err: print('Error with key="%s" : %s' % (key, err.msg)) cnt += 1 # delete handle codes_release(bufr) # close the file f.close() def main(): try: example() except CodesInternalError as err: if VERBOSE: traceback.print_exc(file=sys.stderr) else: sys.stderr.write(err.msg + '\n') return 1 if __name__ == "__main__": sys.exit(main())
bufr_attributes.c
/* * Copyright 2005- ECMWF. * * This software is licensed under the terms of the Apache Licence Version 2.0 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0. * * In applying this licence, ECMWF does not waive the privileges and immunities granted to it by * virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction. */ /* * C Implementation: bufr_attributes * * Description: how to read attributes of keys in BUFR messages. * */ #include "eccodes.h" int main(int argc,char* argv[]) { FILE* in = NULL; /* message handle. Required in all the eccodes calls acting on a message.*/ codes_handle* h=NULL; char* units= NULL; char* unitsPercent= NULL; long longVal; double doubleVal; size_t len=0; int err=0; int cnt=0; const char* infile = "../../data/bufr/syno_multi.bufr"; in=fopen(infile,"rb"); if (!in) { printf("ERROR: unable to open file %s\n", infile); return 1; } /* loop over the messages in the bufr file */ while ((h = codes_handle_new_from_file(NULL, in, PRODUCT_BUFR, &err)) != NULL || err != CODES_SUCCESS) { if (h == NULL) { printf("Error: unable to create handle for message %d\n",cnt); cnt++; continue; } printf("message: %d\n",cnt); /* we need to instruct ecCodes to expand the descriptors i.e. unpack the data values */ CODES_CHECK(codes_set_long(h, "unpack", 1),0); /* ---------------------------------------------------------------- We will read the value and all the attributes available for the 2m temperature. -------------------------------------------------------------------*/ /* get the value as double */ CODES_CHECK(codes_get_double(h, "airTemperatureAt2M", &doubleVal),0); printf(" airTemperatureAt2M: %.2f\n",doubleVal); /* get the element's code (see BUFR code table B) */ CODES_CHECK(codes_get_long(h, "airTemperatureAt2M->code", &longVal),0); printf(" airTemperatureAt2M->code: %ld\n",longVal); /* get the element's units (see BUFR code table B) */ /* get the size and allocate memory*/ CODES_CHECK(codes_get_length(h, "airTemperatureAt2M->units", &len), 0); units = (char*)malloc(len*sizeof(char)); /* get the values*/ codes_get_string(h, "airTemperatureAt2M->units", units, &len); printf(" airTemperatureAt2M->units: %s\n", units); /* get the element's scale (see BUFR code table B) */ CODES_CHECK(codes_get_long(h, "airTemperatureAt2M->scale", &longVal),0); printf(" airTemperatureAt2M->scale: %ld\n",longVal); /* get the element's reference (see BUFR code table B) */ CODES_CHECK(codes_get_long(h, "airTemperatureAt2M->reference", &longVal),0); printf(" airTemperatureAt2M->reference: %ld\n",longVal); /* get the element's width (see BUFR code table B) */ CODES_CHECK(codes_get_long(h, "airTemperatureAt2M->width", &longVal),0); printf(" airTemperatureAt2M->width: %ld\n",longVal); /* ----------------------------------------------------------------- The 2m temperature data element in this message has an associated field: percentConfidence. Its value and attributes can be accessed in a similar manner as was shown above for 2m temperature. ----------------------------------------------------------------- */ /* get the value as long */ CODES_CHECK(codes_get_long(h, "airTemperatureAt2M->percentConfidence", &longVal),0); printf(" airTemperatureAt2M->percentConfidence: %ld\n",longVal); /* get the element's code (see BUFR code table B) */ CODES_CHECK(codes_get_long(h, "airTemperatureAt2M->percentConfidence->code", &longVal),0); printf(" airTemperatureAt2M->percentConfidence->code: %ld\n",longVal); /* get the element's units (see BUFR code table B) */ /* get the size and allocate memory*/ CODES_CHECK(codes_get_length(h, "airTemperatureAt2M->percentConfidence->units", &len), 0); unitsPercent = (char*)malloc(len*sizeof(char)); /* get the values*/ codes_get_string(h, "airTemperatureAt2M->percentConfidence->units", unitsPercent, &len); printf(" airTemperatureAt2M->percentConfidence->units: %s\n", unitsPercent); /* get the element's scale (see BUFR code table B) */ CODES_CHECK(codes_get_long(h, "airTemperatureAt2M->percentConfidence->scale", &longVal),0); printf(" airTemperatureAt2M->percentConfidence->scale: %ld\n",longVal); /* get the element's reference (see BUFR code table B) */ CODES_CHECK(codes_get_long(h, "airTemperatureAt2M->percentConfidence->reference", &longVal),0); printf(" airTemperatureAt2M->percentConfidence->reference: %ld\n",longVal); /* get the element's width (see BUFR code table B) */ CODES_CHECK(codes_get_long(h, "airTemperatureAt2M->percentConfidence->width", &longVal),0); printf(" airTemperatureAt2M->percentConfidence->width: %ld\n",longVal); /* free allocated arrays */ free(units); free(unitsPercent); /* delete handle */ codes_handle_delete(h); cnt++; } fclose(in); return 0; }