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read_grads.pro @ 69

Last change on this file since 69 was 69, checked in by smasson, 18 years ago
debug + new xxx
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1	;------------------------------------------------------------
2	;------------------------------------------------------------
3	;------------------------------------------------------------
4	;+
5	; NAME:read_grads
6	;
7	; PURPOSE:reading grads file (except "data type station" or "grib")
8	; from the grads control file even if there is multiple data files.
9	;
10	; CATEGORY:reading function
11	;
12	; CALLING SEQUENCE:
13	; res=read_grads(var, date1 [, date2], FILENAME = filename)
14	;
15	; INPUTS:
16	; var: the variable name
17	; date1: date of the beginning (yyyymmdd if TIMESTEP is not activate)
18	; date2: last date. Optionnal, if not scpecified date2=date1
19	;
20	; KEYWORD PARAMETERS:
21	;
22	; FILENAME: the grads control file name: 'xxxx.ctl'
23	;
24	; GLAMBOUNDARY (via computegrid.pro):a 2 elements vector,
25	; {lon1,lon2], giving the longitute boundaries that should be
26	; used to visualize the data.
27	; lon2 > lon1
28	; lon2 - lon1 eq 360
29	; key_shift will be automatically defined according to
30	; GLAMBOUNDARY.
31	;
32	; /TIMESTEP: to specify that the dates are time steps instead of
33	; true calendar.
34	;
35	; IODIRECTORY;a string giving the name of iodirectory (see
36	; isafile.pro for all possibilities). default value is common
37	; variable iodir
38	;
39	;---------------
40	; NOT yet available
41	;---------------
42	;
43	; BOX: a 4 or 6 elements 1d array, [lon1,lon2,lat1,lat2, depth1,
44	; depth2], that specifies the area where data must be read
45	;
46	; EVERYTHING
47	;
48	; NOSTRUCTURE
49	;
50	; OUTPUTS: an array
51	;
52	; COMMON BLOCKS:common.pro
53	;
54	; SIDE EFFECTS:define all the grid parameters (defined in common.pro)
55	; associated to the data.
56	;
57	; RESTRICTIONS: this function call the procedure scanfile that use the
58	; unix commands grep and sed
59	;
60	; EXAMPLE:
61	; IDL> a=read_grads('sst',19900101,19900131,filename='outputs.ctl')
62	; IDL> plt, a
63	;
64	; MODIFICATION HISTORY:Sebastien Masson (smasson@lodyc.jussieu.fr)
65	;
66	;-
67	;------------------------------------------------------------
68	;------------------------------------------------------------
69	;------------------------------------------------------------
70
71	FUNCTION read_grads, var, date1, date2, FILENAME = filename, BOX=box, TIMESTEP = timestep, EVERYTHING = everything, NOSTRUCT = nostruct, _EXTRA = ex
72	;---------------------------------------------------------
73	@cm_4mesh
74	@cm_4data
75	@cm_4cal
76	IF NOT keyword_set(key_forgetold) THEN BEGIN
77	@updatenew
78	ENDIF
79	;------------------------------------------------------------
80	; we find the filename.
81	;------------------------------------------------------------
82	filename = isafile(FILENAME = filename, IODIRECTORY = iodir, _EXTRA = ex)
83	if size(filename, /type) NE 7 then $
84	return, report('read_ncdf cancelled')
85	;------------------------------------------------------------
86	; we scan the control file called filename
87	;------------------------------------------------------------
88	scanctl, filename, filesname, jpt1file, varsname, varslev, swapbytes, bigendian, littleendian, f77sequential, fileheader, theader, xyheader, VARFMT = varfmt, _EXTRA = ex
89	if n_elements(varfmt) EQ 0 then varfmt = 'float'
90	;------------------------
91	;------------------------
92	; check date1 and date2 and found the starting index "t1" and the
93	; ending index "t2" that corresponds to the time series specified by
94	; date1 and date2 for the time axis defined in the .ctl file.
95	;------------------------
96	;------------------------
97	if n_elements(date1) EQ 0 then begin
98	t0 = 0
99	t1 = 0
100	ENDIF
101	if n_elements(date2) EQ 0 then date2 = date1
102	if keyword_set(timestep) then BEGIN
103	if date1 GT date2 then begin
104	print, 'date2 must be larger than date1'
105	return, -1
106	endif
107	t1 = 0 > long(date1) < (jpt-1)
108	t2 = t1 > long(date2) < (jpt-1)
109	ENDIF ELSE BEGIN
110	jdate1 = date2jul(date1, /grads) < time[jpt-1]
111	jdate2 = time[0] > date2jul(date2, /grads)
112	if jdate1 GT jdate2 then begin
113	print, 'date2 must be larger than date1'
114	return, -1
115	endif
116	t1 = (where(time GE jdate1))[0]
117	tmp = where(time LE jdate2, t2)
118	t2 = t2-1
119	ENDELSE
120	if t2 LT t1 then begin
121	print, 'There is no date between date1 and date2'
122	return, -1
123	endif
124	jpt2read = t2-t1+1
125	;------------------------
126	;------------------------
127	; index of the variable
128	;------------------------
129	;------------------------
130	varid = where(strlowcase(varsname) EQ strlowcase(var))
131	varid = varid[0]
132	if varid EQ -1 then begin
133	print, var+' not found in the variable liste of '+filename
134	return, -1
135	ENDIF
136	varname = var
137	if varslev[varid] EQ 1 then res = fltarr(jpi, jpj, jpt2read, /nozero) $
138	ELSE res = fltarr(jpi, jpj, varslev[varid], jpt2read, /nozero)
139	;------------------------
140	;------------------------
141	; find the first file to be read according to the lile list,, the
142	; number of time step in each file and t1 and t2
143	;------------------------
144	;------------------------
145	indf2read = t1/jpt1file
146	startread = t1-indf2read*jpt1file
147	alreadyread = 0
148	readagain:
149	jpt2read1file = min([jpt1file-startread, jpt2read])
150	f2read = filesname[indf2read]
151	;------------------------
152	;------------------------
153	; opening
154	;------------------------
155	;------------------------;
156	; check the existance of the file
157	f2read = isafile(filename = f2read, iodirectory = iodir, _EXTRA = ex)
158	; if the file is stored on tape
159	if !version.os_family EQ 'unix' then spawn, 'file '+f2read+' > /dev/null'
160	; open the file
161	openr, unit, f2read, /get_lun, error=err $
162	, swap_if_little_endian = bigendian $
163	, swap_if_big_endian = littleendian $
164	, swap_endian = swapbytes
165	if err ne 0 then begin
166	print,!err_string
167	return, -1
168	endif
169	;------------------------
170	case varfmt of
171	'byte':fmtsz = 1l
172	'uint':fmtsz = 2l
173	'int':fmtsz = 2l
174	'long':fmtsz = 4l
175	'float':fmtsz = 4l
176	endcase
177	;------------------------
178	; check its size
179	addf77sec = long(42f77sequential)
180	xyblocsize = xyheader + addf77sec(xyheader NE 0) + jpijpj*fmtsz +addf77sec
181	nxybloc = long(total(varslev))
182	filesize = (fileheader + addf77sec*(fileheader NE 0)) $
183	+(theader+addf77sec(theader NE 0) + nxyblocxyblocsize)*jpt1file
184	infof2read=fstat(unit)
185	if infof2read.size NE filesize then begin
186	print, 'According to '+filename+' the file size must be '+strtrim(filesize, 1)+' instead of '+strtrim(infof2read.size, 1)
187	print, 'jpi: '+strtrim(jpi, 2)
188	print, 'jpj: '+strtrim(jpj, 2)
189	print, 'jpt: '+strtrim(jpt, 2)
190	print, 'format size in byte: '+strtrim(fmtsz, 2)
191	print, 'number of xy arrays: '+strtrim(nxybloc, 2)
192	return, -1
193	endif
194	;------------------------
195	;------------------------
196	; reading
197	;------------------------
198	;------------------------;
199	;------------------------;
200	; loop on the time steps to be read in one file
201	for i = 0, jpt2read1file-1 do begin
202	; computing the offset
203	offset = (fileheader + addf77sec*(fileheader NE 0)) $
204	+(theader+addf77sec(theader NE 0) + nxyblocxyblocsize)*(startread+i) $
205	+theader+addf77sec*(theader NE 0)
206	if varid NE 0 THEN $
207	offset = offset + long(total(varslev[0:varid-1]))*xyblocsize
208	; if there is only one level
209	IF varslev[varid] EQ 1 then begin
210	case varfmt of
211	'byte':a=assoc(unit, bytarr(jpi,jpj,/nozero), offset+4*f77sequential)
212	'uint':a=assoc(unit,uintarr(jpi,jpj,/nozero), offset+4*f77sequential)
213	'int':a=assoc(unit, intarr(jpi,jpj,/nozero), offset+4*f77sequential)
214	'long':a=assoc(unit, lonarr(jpi,jpj,/nozero), offset+4*f77sequential)
215	'float':a=assoc(unit,fltarr(jpi,jpj,/nozero), offset+4*f77sequential)
216	endcase
217	res[, , i+alreadyread]=a[0]
218	ENDIF ELSE BEGIN ; more than 1 level to be read
219	if f77sequential then BEGIN ; sequential access
220	case varfmt of
221	'byte':a=assoc(unit, bytarr(jpi*jpj+8, varslev[varid],/nozero), offset)
222	'uint':a=assoc(unit,uintarr(jpi*jpj+4, varslev[varid],/nozero), offset)
223	'int':a=assoc(unit, intarr(jpi*jpj+4, varslev[varid],/nozero), offset)
224	'long':a=assoc(unit, lonarr(jpi*jpj+2, varslev[varid],/nozero), offset)
225	'float':a=assoc(unit,fltarr(jpi*jpj+2, varslev[varid],/nozero), offset)
226	endcase
227	tmp = a[0]
228	case varfmt OF ; we cut the headers and tailers of f77 write
229	'byte': tmp = tmp[4:jpijpj+3, ]
230	'uint': tmp = tmp[2:jpijpj+1, ]
231	'int': tmp = tmp[2:jpijpj+1, ]
232	'long': tmp = tmp[1:jpijpj+0, ]
233	'float':tmp = tmp[1:jpijpj+0, ]
234	endcase
235	if keyword_set(key_zreverse) then res[, , , i+alreadyread]=reverse(reform(tmp, jpi, jpj, varslev[varid], /over), 3) ELSE res[, , , i+alreadyread]=reform(tmp, jpi, jpj, varslev[varid], /over)
236	ENDIF ELSE BEGIN ; direct acces
237	case varfmt of
238	'byte':a=assoc(unit, bytarr(jpi,jpj,varslev[varid],/nozero),offset)
239	'uint':a=assoc(unit,uintarr(jpi,jpj,varslev[varid],/nozero),offset)
240	'int':a=assoc(unit, intarr(jpi,jpj,varslev[varid],/nozero),offset)
241	'long':a=assoc(unit, lonarr(jpi,jpj,varslev[varid],/nozero),offset)
242	'float':a=assoc(unit,fltarr(jpi,jpj,varslev[varid],/nozero),offset)
243	endcase
244	if keyword_set(key_zreverse) then res[, , , i+alreadyread]=reverse(a[0], 3) ELSE res[, , , i+alreadyread]=a[0]
245	ENDELSE
246	ENDELSE
247	endfor
248	;------------------------
249	; close the file
250	free_lun,unit
251	close,unit
252	;------------------------
253	;------------------------
254	; do we need to read a new file to complete the time series ?
255	;------------------------
256	;------------------------
257	if jpt2read1file NE jpt2read then BEGIN
258	indf2read = indf2read+1
259	startread = 0
260	alreadyread = alreadyread+jpt2read1file
261	jpt2read = jpt2read-jpt2read1file
262	GOTO, readagain
263	ENDIF
264	;------------------------
265	;------------------------
266	; post processing
267	;------------------------
268	;------------------------
269	if keyword_set(key_yreverse) then res = reverse(res, 2)
270	if keyword_set(key_shift) then begin
271	case (size(res))[0] of
272	2:res = shift(res, key_shift, 0)
273	3:res = shift(res, key_shift, 0, 0)
274	4:res = shift(res, key_shift, 0, 0, 0)
275	endcase
276	endif
277	;------------------------
278	; mask
279	; IF varslev[varid] EQ 1 then begin
280	; if abs(valmask) LE 1e5 then notgood = where(res[, , 0] EQ valmask) $
281	; ELSE notgood = where(abs(res[, , 0]) GE abs(valmask)/10)
282	; if notgood[0] NE -1 then tmask[notgood] = 0b
283	; ENDIF ELSE BEGIN
284	; if abs(valmask) LE 1e5 then notgood = where(res[, , *, 0] EQ valmask) $
285	; ELSE notgood = where(abs(res[, , *, 0]) GE abs(valmask)/10)
286	; if notgood[0] NE -1 then tmask[notgood] = 0b
287	; ENDELSE
288	if abs(valmask) LE 1e5 then notgood = where(res EQ valmask) $
289	ELSE notgood = where(abs(res) GE abs(valmask)/10)
290	if notgood[0] NE -1 THEN res[notgood] = !values.f_nan
291	; valmask = 1e20
292	; if abs(valmask) LE 1e5 then notgood = where(res EQ valmask) $
293	; ELSE notgood = where(abs(res) GE abs(valmask)/10)
294	; if notgood[0] NE -1 THEN res[notgood] = 1e20
295	; valmask = 1e20
296	triangles_list = triangule()
297	;------------------------
298	; subdomain extration
299
300	;------------------------
301	; time aguments
302	;------------------------
303	time = time[t1:t2]
304	jpt = t2-t1+1
305	if keyword_set(timestep) then vardate = strtrim(time[0], 2) $
306	ELSE vardate = date2string(vairdate(time[0]))
307	;------------------------
308	@updateold
309	;------------------------
310
311	return, res
312	end

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