mirror of https://github.com/ecmwf/eccodes.git
74 lines
1.6 KiB
Python
74 lines
1.6 KiB
Python
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import traceback
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import sys
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from gribapi import *
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INPUT='../../data/tp_ecmwf.grib'
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OUTPUT='out.grib'
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VERBOSE=1 # verbose error reporting
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def example():
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sample_id = grib_new_from_samples("regular_ll_sfc_grib1")
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fin = open(INPUT)
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fout = open(OUTPUT,'w')
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keys = {
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'dataDate':20080104,
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'startStep':0,
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'endStep':12,
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'stepType':'accum',
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'table2Version':2,
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'indicatorOfParameter':61,
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'decimalPrecision':2,
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}
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prev_vals = None
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while 1:
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gid = grib_new_from_file(fin)
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if gid is None: break
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curr_vals = grib_get_values(gid)
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if prev_vals is None:
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result = prev_vals = curr_vals
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else:
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try:
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# works with NumPy
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result = curr_vals - prev_vals
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except TypeError: # but not with array
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result = curr_vals
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for i in range(len(result)):
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result[i] -= prev_vals[i]
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prev_vals = curr_vals
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keys['startStep'] += 12
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keys['endStep'] += 12
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clone_id = grib_clone(sample_id)
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for key in keys:
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grib_set(clone_id,key,keys[key])
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grib_set_values(clone_id,result * 1000)
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grib_write(clone_id,fout)
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grib_release(gid)
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fin.close()
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fout.close()
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def main():
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try:
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example()
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except GribInternalError,err:
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if VERBOSE:
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traceback.print_exc(file=sys.stderr)
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else:
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print >>sys.stderr,err.msg
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return 1
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if __name__ == "__main__":
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sys.exit(main())
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