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source: flex_extract.git/Source/Python/Classes/GribUtil.py @ 44174de

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Last change on this file since 44174de was 44174de, checked in by Anne Philipp <anne.philipp@…>, 5 years ago
commented out the WRF parts since they are still under construction and added License SPDX tags
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1	#!/usr/bin/env python3
2	# -- coding: utf-8 --
3	#*******************************************************************************
4	# @Author: Anne Fouilloux (University of Oslo)
5	#
6	# @Date: July 2014
7	#
8	# @Change History:
9	# February 2018 - Anne Philipp (University of Vienna):
10	# - applied PEP8 style guide
11	# - added documentation
12	# - changed some naming
13	#
14	# @License:
15	# (C) Copyright 2014-2019.
16	# Anne Philipp, Leopold Haimberger
17	#
18	# SPDX-License-Identifier: CC-BY-4.0
19	#
20	# This work is licensed under the Creative Commons Attribution 4.0
21	# International License. To view a copy of this license, visit
22	# http://creativecommons.org/licenses/by/4.0/ or send a letter to
23	# Creative Commons, PO Box 1866, Mountain View, CA 94042, USA.
24	#*******************************************************************************
25
26	# ------------------------------------------------------------------------------
27	# MODULES
28	# ------------------------------------------------------------------------------
29	from __future__ import print_function
30
31	import os
32
33	# ------------------------------------------------------------------------------
34	# CLASS
35	# ------------------------------------------------------------------------------
36	class GribUtil(object):
37	'''
38	Class for GRIB utilities (new methods) based on GRIB API
39
40	The GRIB API provides all necessary tools to work directly with the
41	grib files. Nevertheless, the GRIB API tools are very basic and are in
42	direct connection with the grib files. This class provides some higher
43	functions which apply a set of GRIB API tools together in the respective
44	context. So, the class initially contains a list of grib files (their
45	names) and the using program then applies the methods directly on the
46	class objects without having to think about how the actual GRIB API
47	tools have to be arranged.
48	'''
49	# --------------------------------------------------------------------------
50	# CLASS FUNCTIONS
51	# --------------------------------------------------------------------------
52	def __init__(self, filenames):
53	'''Initialise an object of GribUtil and assign a list of filenames.
54
55	Parameters
56	----------
57	filenames : :obj:`list` of :obj:`strings`
58	A list of filenames.
59
60	Return
61	------
62
63	'''
64
65	self.filenames = filenames
66
67	return
68
69
70	def get_keys(self, keynames, wherekeynames=[], wherekeyvalues=[]):
71	'''Get keyvalues for a given list of keynames a where statement
72	can be given (list of key and list of values)
73
74	Parameters
75	----------
76	keynames : :obj:`list` of :obj:`string`
77	List of keynames.
78
79	wherekeynames : :obj:`list` of :obj:`string`, optional
80	Default value is an empty list.
81
82	wherekeyvalues : :obj:`list` of :obj:`string`, optional
83	Default value is an empty list.
84
85	Return
86	------
87	return_list : :obj:`list` of :obj:`string`
88	List of keyvalues for given keynames.
89	'''
90	from eccodes import (codes_new_from_file, codes_is_defined, codes_get,
91	codes_release)
92
93	fileid = open(self.filenames, 'r')
94
95	return_list = []
96
97	while 1:
98	gid = codes_new_from_file(fileid)
99
100	if gid is None:
101	break
102
103	if len(wherekeynames) != len(wherekeyvalues):
104	raise Exception("Number of key values and key names must be \
105	the same. Give a value for each keyname!")
106
107	select = True
108	i = 0
109	for wherekey in wherekeynames:
110	if not codes_is_defined(gid, wherekey):
111	raise Exception("where key was not defined")
112
113	select = (select and (str(wherekeyvalues[i]) ==
114	str(codes_get(gid, wherekey))))
115	i += 1
116
117	if select:
118	llist = []
119	for key in keynames:
120	llist.extend([str(codes_get(gid, key))])
121	return_list.append(llist)
122
123	codes_release(gid)
124
125	fileid.close()
126
127	return return_list
128
129
130	def set_keys(self, fromfile, keynames, keyvalues, wherekeynames=[],
131	wherekeyvalues=[], strict=False, filemode='w'):
132	'''Opens the file to read the grib messages and then write
133	the selected messages (with wherekeys) to a new output file.
134	Also, the keyvalues of the passed list of keynames are set.
135
136	Parameters
137	----------
138	fromfile : :obj:`string`
139	Filename of the input file to read the grib messages from.
140
141	keynames : :obj:`list` of :obj:`string`
142	List of keynames to set in the selected messages.
143	Default is an empty list.
144
145	keyvalues : :obj:`list` of :obj:`string`
146	List of keyvalues to set in the selected messages.
147	Default is an empty list.
148
149	wherekeynames : :obj:`list` of :obj:`string`, optional
150	List of keynames to select correct message.
151	Default value is an empty list.
152
153	wherekeyvalues : :obj:`list` of :obj:`string`, optional
154	List of keyvalues for keynames to select correct message.
155	Default value is an empty list.
156
157	strict : :obj:`boolean`, optional
158	Decides if everything from keynames and keyvalues
159	is written out the grib file (False) or only those
160	meeting the where statement (True). Default is False.
161
162	filemode : :obj:`string`, optional
163	Sets the mode for the output file. Default is "w".
164
165	Return
166	------
167
168	'''
169	from eccodes import (codes_grib_new_from_file, codes_is_defined,
170	codes_get, codes_set, codes_write,
171	codes_set_values, codes_release)
172
173	if len(wherekeynames) != len(wherekeyvalues):
174	raise Exception("Give a value for each keyname!")
175
176	fout = open(self.filenames, filemode)
177	fin = open(fromfile)
178
179	while 1:
180	gid = codes_grib_new_from_file(fin)
181
182	if gid is None:
183	break
184
185	select = True
186	i = 0
187	for wherekey in wherekeynames:
188	if not codes_is_defined(gid, wherekey):
189	raise Exception("wherekey was not defined")
190
191	select = (select and (str(wherekeyvalues[i]) ==
192	str(codes_get(gid, wherekey))))
193	i += 1
194
195	if select:
196	i = 0
197	for key in keynames:
198	if key == 'values':
199	codes_set_values(gid, keyvalues[i])
200	else:
201	codes_set(gid, key, keyvalues[i])
202	i += 1
203
204	codes_write(gid, fout)
205
206	codes_release(gid)
207
208	fin.close()
209	fout.close()
210
211	return
212
213	def copy_dummy_msg(self, filename_in, selectWhere=True,
214	keynames=[], keyvalues=[], filemode='w'):
215	'''Add the content of another input grib file to the objects file but
216	only messages corresponding to keys/values passed to the function.
217	The selectWhere switch decides if to copy the keys equal to (True) or
218	different to (False) the keynames/keyvalues list passed to the function.
219
220	Parameters
221	----------
222	filename_in : :obj:`string`
223	Filename of the input file to read the grib messages from.
224
225	selectWhere : :obj:`boolean`, optional
226	Decides if to copy the keynames and values equal to (True) or
227	different to (False) the keynames/keyvalues list passed to the
228	function. Default is True.
229
230	keynames : :obj:`list` of :obj:`string`, optional
231	List of keynames. Default is an empty list.
232
233	keyvalues : :obj:`list` of :obj:`string`, optional
234	List of keyvalues. Default is an empty list.
235
236	filemode : :obj:`string`, optional
237	Sets the mode for the output file. Default is "w".
238
239	Return
240	------
241
242	'''
243	from eccodes import (codes_grib_new_from_file, codes_is_defined,
244	codes_get, codes_release, codes_write)
245
246	if len(keynames) != len(keyvalues):
247	raise Exception("Give a value for each keyname!")
248
249	fin = open(filename_in, 'rb')
250	fout = open(self.filenames, filemode)
251
252	fields = 0
253
254	while fields < 1:
255	gid = codes_grib_new_from_file(fin)
256
257	if gid is None:
258	break
259
260	select = True
261	i = 0
262	for key in keynames:
263	if not codes_is_defined(gid, key):
264	raise Exception("Key was not defined")
265
266	if selectWhere:
267	select = (select and (str(keyvalues[i]) ==
268	str(codes_get(gid, key))))
269	else:
270	select = (select and (str(keyvalues[i]) !=
271	str(codes_get(gid, key))))
272	i += 1
273
274	if select:
275	fields = fields + 1
276	codes_write(gid, fout)
277
278	codes_release(gid)
279
280	fin.close()
281	fout.close()
282
283	return
284
285	def index(self, index_keys=["mars"], index_file="my.idx"):
286	'''Create index file from a list of files if it does not exist or
287	read an index file.
288
289	Parameters
290	----------
291	index_keys: :obj:`list` of :obj:`string`, optional
292	Contains the list of key parameter names from
293	which the index is to be created.
294	Default is a list with a single entry string "mars".
295
296	index_file: :obj:`string`, optional
297	Filename where the indices are stored.
298	Default is "my.idx".
299
300	Return
301	------
302	iid: :obj:`integer`
303	Grib index id.
304	'''
305	from eccodes import (codes_index_read, codes_index_new_from_file,
306	codes_index_add_file, codes_index_write)
307
308	print("... index will be done")
309	iid = None
310
311	if os.path.exists(index_file):
312	iid = codes_index_read(index_file)
313	print("Use existing index file: %s " % (index_file))
314	else:
315	for filename in self.filenames:
316	print("Inputfile: %s " % (filename))
317	if iid is None:
318	iid = codes_index_new_from_file(filename, index_keys)
319	else:
320	codes_index_add_file(iid, filename)
321
322	if iid is not None:
323	codes_index_write(iid, index_file)
324
325	print('... index done')
326
327	return iid

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