ps:最近用vc作遥感影像的入库功能，借助GDAL来做，基本已经可以使用了。最后要写段代码对建立好的金字塔作合并输出，再次翻看了gdal_merge.py，其实这段代码很早就看过，尽管道理不复杂，但看到Frank把代码写的这么精致，不由肃然起敬，放到这里经常来看看勉励自己。
写代码有好几年了，现在才深刻体会到软件设计模式、架构、文档、规范的重要性，反而感觉做工作时有些瞻前顾后，总想把代码的逻辑整的很清晰以提高可维护行和复用性，真是那个 阶段有哪个阶段的烦恼，呵呵！
1 #!/usr/bin/env python
2 ###############################################################################
3 # $Id: gdal_merge.py,v 1.25 2006/04/20 13:27:57 fwarmerdam Exp $
4 #
5 # Project: InSAR Peppers
6 # Purpose: Module to extract data from many rasters into one output.
7 # Author: Frank Warmerdam, warmerdam@pobox.com
8 #
9 ###############################################################################
10 # Copyright (c) 2000, Atlantis Scientific Inc. (www.atlsci.com)
11 #
12 # This library is free software; you can redistribute it and/or
13 # modify it under the terms of the GNU Library General Public
14 # License as published by the Free Software Foundation; either
15 # version 2 of the License, or (at your option) any later version.
16 #
17 # This library is distributed in the hope that it will be useful,
18 # but WITHOUT ANY WARRANTY; without even the implied warranty of
19 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 # Library General Public License for more details.
21 #
22 # You should have received a copy of the GNU Library General Public
23 # License along with this library; if not, write to the
24 # Free Software Foundation, Inc., 59 Temple Place - Suite 330,
25 # Boston, MA 02111-1307, USA.
26 ###############################################################################
27 #
28 # $Log: gdal_merge.py,v $
29 # Revision 1.25 2006/04/20 13:27:57 fwarmerdam
30 # Added error checks on Driver's Create support and success of Create.
31 #
32 # Revision 1.24 2006/01/26 23:40:39 fwarmerdam
33 # treat nodata as a float.
34 #
35 # Revision 1.23 2005/11/25 02:13:36 fwarmerdam
36 # Added --help-general.
37 #
38 # Revision 1.22 2005/11/16 18:30:49 fwarmerdam
39 # Fixed round off issue with output file size.
40 #
41 # Revision 1.21 2005/08/18 15:45:15 fwarmerdam
42 # Added the -createonly switch.
43 #
44 # Revision 1.20 2005/07/19 03:33:39 fwarmerdam
45 # removed left over global_list
46 #
47 # Revision 1.19 2005/06/23 19:51:51 fwarmerdam
48 # Fixed support for non-square pixels c/o Matt Giger
49 # http://bugzilla.remotesensing.org/show_bug.cgi?id=874
50 #
51 # Revision 1.18 2005/03/29 22:40:00 fwarmerdam
52 # Added -ot option.
53 #
54 # Revision 1.17 2005/02/23 18:29:07 fwarmerdam
55 # Accept "either spelling" of separate.
56 #
57 # Revision 1.16 2005/02/23 18:23:00 fwarmerdam
58 # Added -seperate to the usage message.
59 #
60 # Revision 1.15 2004/09/02 22:06:24 warmerda
61 # Added a bit of commandline error reporting.
62 #
63 # Revision 1.14 2004/08/23 15:05:27 warmerda
64 # Added projection setting for new files.
65 #
66 # Revision 1.13 2004/04/02 22:31:26 warmerda
67 # Use -of for format.
68 #
69 # Revision 1.12 2004/04/02 17:40:44 warmerda
70 # added GDALGeneralCmdLineProcessor() support
71 #
72 # Revision 1.11 2004/03/26 17:11:42 warmerda
73 # added -init
74 #
75 # Revision 1.10 2003/04/22 14:42:45 warmerda
76 # Don't import Numeric unless we need it.
77 #
78 # Revision 1.9 2003/04/22 13:30:05 warmerda
79 # Added -co flag.
80 #
81 # Revision 1.8 2003/03/07 16:26:39 warmerda
82 # fixed up for ungeoreferenced files, supress extra error
83 #
84 # Revision 1.7 2003/01/28 15:00:13 warmerda
85 # applied patch for multi-band support from Ken Boss
86 #
87 # Revision 1.6 2003/01/20 22:19:08 warmerda
88 # added nodata support
89 #
90 # Revision 1.5 2002/12/12 14:54:42 warmerda
91 # added the -pct flag to copy over a pct
92 #
93 # Revision 1.4 2002/12/12 14:48:12 warmerda
94 # removed broken options arg to gdal.Create()
95 #
96 # Revision 1.3 2002/04/03 21:12:05 warmerda
97 # added -separate flag for Gerald Buckmaster
98 #
99 # Revision 1.2 2000/11/29 20:36:18 warmerda
100 # allow output file to be preexisting
101 #
102 # Revision 1.1 2000/11/29 20:23:13 warmerda
103 # New
104 #
105 #
106
107 import gdal
108 import sys
109
110 verbose = 0
111
112
113 # =============================================================================
114 def raster_copy( s_fh, s_xoff, s_yoff, s_xsize, s_ysize, s_band_n,
115 t_fh, t_xoff, t_yoff, t_xsize, t_ysize, t_band_n,
116 nodata=None ):
117
118 if nodata is not None:
119 return raster_copy_with_nodata(
120 s_fh, s_xoff, s_yoff, s_xsize, s_ysize, s_band_n,
121 t_fh, t_xoff, t_yoff, t_xsize, t_ysize, t_band_n,
122 nodata )
123
124 if verbose != 0:
125 print 'Copy %d,%d,%d,%d to %d,%d,%d,%d.' \
126 % (s_xoff, s_yoff, s_xsize, s_ysize,
127 t_xoff, t_yoff, t_xsize, t_ysize )
128
129 s_band = s_fh.GetRasterBand( s_band_n )
130 t_band = t_fh.GetRasterBand( t_band_n )
131
132 data = s_band.ReadRaster( s_xoff, s_yoff, s_xsize, s_ysize,
133 t_xsize, t_ysize, t_band.DataType )
134 t_band.WriteRaster( t_xoff, t_yoff, t_xsize, t_ysize,
135 data, t_xsize, t_ysize, t_band.DataType )
136
137
138 return 0
139
140 # =============================================================================
141 def raster_copy_with_nodata( s_fh, s_xoff, s_yoff, s_xsize, s_ysize, s_band_n,
142 t_fh, t_xoff, t_yoff, t_xsize, t_ysize, t_band_n,
143 nodata ):
144
145 import Numeric
146
147 if verbose != 0:
148 print 'Copy %d,%d,%d,%d to %d,%d,%d,%d.' \
149 % (s_xoff, s_yoff, s_xsize, s_ysize,
150 t_xoff, t_yoff, t_xsize, t_ysize )
151
152 s_band = s_fh.GetRasterBand( s_band_n )
153 t_band = t_fh.GetRasterBand( t_band_n )
154
155 data_src = s_band.ReadAsArray( s_xoff, s_yoff, s_xsize, s_ysize,
156 t_xsize, t_ysize )
157 data_dst = t_band.ReadAsArray( t_xoff, t_yoff, t_xsize, t_ysize )
158
159 nodata_test = Numeric.equal(data_src,nodata)
160 to_write = Numeric.choose( nodata_test, (data_src, data_dst) )
161
162 t_band.WriteArray( to_write, t_xoff, t_yoff )
163
164 return 0
165
166 # =============================================================================
167 def names_to_fileinfos( names ):
168 """
169 Translate a list of GDAL filenames, into file_info objects.
170
171 names -- list of valid GDAL dataset names.
172
173 Returns a list of file_info objects. There may be less file_info objects
174 than names if some of the names could not be opened as GDAL files.
175 """
176
177 file_infos = []
178 for name in names:
179 fi = file_info()
180 if fi.init_from_name( name ) == 1:
181 file_infos.append( fi )
182
183 return file_infos
184
185 # *****************************************************************************
186 class file_info:
187 """A class holding information about a GDAL file."""
188
189 def init_from_name(self, filename):
190 """
191 Initialize file_info from filename
192
193 filename -- Name of file to read.
194
195 Returns 1 on success or 0 if the file can't be opened.
196 """
197 fh = gdal.Open( filename )
198 if fh is None:
199 return 0
200
201 self.filename = filename
202 self.bands = fh.RasterCount
203 self.xsize = fh.RasterXSize
204 self.ysize = fh.RasterYSize
205 self.band_type = fh.GetRasterBand(1).DataType
206 self.projection = fh.GetProjection()
207 self.geotransform = fh.GetGeoTransform()
208 self.ulx = self.geotransform[0]
209 self.uly = self.geotransform[3]
210 self.lrx = self.ulx + self.geotransform[1] * self.xsize
211 self.lry = self.uly + self.geotransform[5] * self.ysize
212
213 ct = fh.GetRasterBand(1).GetRasterColorTable()
214 if ct is not None:
215 self.ct = ct.Clone()
216 else:
217 self.ct = None
218
219 return 1
220
221 def report( self ):
222 print 'Filename: '+ self.filename
223 print 'File Size: %dx%dx%d' \
224 % (self.xsize, self.ysize, self.bands)
225 print 'Pixel Size: %f x %f' \
226 % (self.geotransform[1],self.geotransform[5])
227 print 'UL:(%f,%f) LR:(%f,%f)' \
228 % (self.ulx,self.uly,self.lrx,self.lry)
229
230 def copy_into( self, t_fh, s_band = 1, t_band = 1, nodata_arg=None ):
231 """
232 Copy this files image into target file.
233
234 This method will compute the overlap area of the file_info objects
235 file, and the target gdal.Dataset object, and copy the image data
236 for the common window area. It is assumed that the files are in
237 a compatible projection
no checking or warping is done. However,
238 if the destination file is a different resolution, or different
239 image pixel type, the appropriate resampling and conversions will
240 be done (using normal GDAL promotion/demotion rules).
241
242 t_fh -- gdal.Dataset object for the file into which some or all
243 of this file may be copied.
244
245 Returns 1 on success (or if nothing needs to be copied), and zero one
246 failure.
247 """
248 t_geotransform = t_fh.GetGeoTransform()
249 t_ulx = t_geotransform[0]
250 t_uly = t_geotransform[3]
251 t_lrx = t_geotransform[0] + t_fh.RasterXSize * t_geotransform[1]
252 t_lry = t_geotransform[3] + t_fh.RasterYSize * t_geotransform[5]
253
254 # figure out intersection region
255 tgw_ulx = max(t_ulx,self.ulx)
256 tgw_lrx = min(t_lrx,self.lrx)
257 if t_geotransform[5] < 0:
258 tgw_uly = min(t_uly,self.uly)
259 tgw_lry = max(t_lry,self.lry)
260 else:
261 tgw_uly = max(t_uly,self.uly)
262 tgw_lry = min(t_lry,self.lry)
263
264 # do they even intersect?
265 if tgw_ulx >= tgw_lrx:
266 return 1
267 if t_geotransform[5] < 0 and tgw_uly <= tgw_lry:
268 return 1
269 if t_geotransform[5] > 0 and tgw_uly >= tgw_lry:
270 return 1
271
272 # compute target window in pixel coordinates.
273 tw_xoff = int((tgw_ulx - t_geotransform[0]) / t_geotransform[1] + 0.1)
274 tw_yoff = int((tgw_uly - t_geotransform[3]) / t_geotransform[5] + 0.1)
275 tw_xsize = int((tgw_lrx - t_geotransform[0])/t_geotransform[1] + 0.5) \
276 - tw_xoff
277 tw_ysize = int((tgw_lry - t_geotransform[3])/t_geotransform[5] + 0.5) \
278 - tw_yoff
279
280 if tw_xsize < 1 or tw_ysize < 1:
281 return 1
282
283 # Compute source window in pixel coordinates.
284 sw_xoff = int((tgw_ulx - self.geotransform[0]) / self.geotransform[1])
285 sw_yoff = int((tgw_uly - self.geotransform[3]) / self.geotransform[5])
286 sw_xsize = int((tgw_lrx - self.geotransform[0]) \
287 / self.geotransform[1] + 0.5) - sw_xoff
288 sw_ysize = int((tgw_lry - self.geotransform[3]) \
289 / self.geotransform[5] + 0.5) - sw_yoff
290
291 if sw_xsize < 1 or sw_ysize < 1:
292 return 1
293
294 # Open the source file, and copy the selected region.
295 s_fh = gdal.Open( self.filename )
296
297 return \
298 raster_copy( s_fh, sw_xoff, sw_yoff, sw_xsize, sw_ysize, s_band,
299 t_fh, tw_xoff, tw_yoff, tw_xsize, tw_ysize, t_band,
300 nodata_arg )
301
302
303 # =============================================================================
304 def Usage():
305 print 'Usage: gdal_merge.py [-o out_filename] [-of out_format] [-co NAME=VALUE]*'
306 print ' [-ps pixelsize_x pixelsize_y] [-separate] [-v] [-pct]'
307 print ' [-ul_lr ulx uly lrx lry] [-n nodata_value] [-init value]'
308 print ' [-ot datatype] [-createonly] input_files'
309 print ' [--help-general]'
310 print
311
312 # =============================================================================
313 #
314 # Program mainline.
315 #
316
317 if __name__ == '__main__':
318
319 names = []
320 format = 'GTiff'
321 out_file = 'out.tif'
322
323 ulx = None
324 psize_x = None
325 separate = 0
326 copy_pct = 0
327 nodata = None
328 create_options = []
329 pre_init = None
330 band_type = None
331 createonly = 0
332
333 gdal.AllRegister()
334 argv = gdal.GeneralCmdLineProcessor( sys.argv )
335 if argv is None:
336 sys.exit( 0 )
337
338 # Parse command line arguments.
339 i = 1
340 while i < len(argv):
341 arg = argv[i]
342
343 if arg == '-o':
344 i = i + 1
345 out_file = argv[i]
346
347 elif arg == '-v':
348 verbose = 1
349
350 elif arg == '-createonly':
351 createonly = 1
352
353 elif arg == '-separate':
354 separate = 1
355
356 elif arg == '-seperate':
357 separate = 1
358
359 elif arg == '-pct':
360 copy_pct = 1
361
362 elif arg == '-ot':
363 i = i + 1
364 band_type = gdal.GetDataTypeByName( argv[i] )
365 if band_type == gdal.GDT_Unknown:
366 print 'Unknown GDAL data type: ', argv[i]
367 sys.exit( 1 )
368
369 elif arg == '-init':
370 i = i + 1
371 pre_init = float(argv[i])
372
373 elif arg == '-n':
374 i = i + 1
375 nodata = float(argv[i])
376
377 elif arg == '-f':
378 # for backward compatibility.
379 i = i + 1
380 format = argv[i]
381
382 elif arg == '-of':
383 i = i + 1
384 format = argv[i]
385
386 elif arg == '-co':
387 i = i + 1
388 create_options.append( argv[i] )
389
390 elif arg == '-ps':
391 psize_x = float(argv[i+1])
392 psize_y = -1 * abs(float(argv[i+2]))
393 i = i + 2
394
395 elif arg == '-ul_lr':
396 ulx = float(argv[i+1])
397 uly = float(argv[i+2])
398 lrx = float(argv[i+3])
399 lry = float(argv[i+4])
400 i = i + 4
401
402 elif arg[:1] == '-':
403 print 'Unrecognised command option: ', arg
404 Usage()
405 sys.exit( 1 )
406
407 else:
408 names.append( arg )
409
410 i = i + 1
411
412 if len(names) == 0:
413 print 'No input files selected.'
414 Usage()
415 sys.exit( 1 )
416
417 Driver = gdal.GetDriverByName(format)
418 if Driver is None:
419 print 'Format driver %s not found, pick a supported driver.' % format
420 sys.exit( 1 )
421
422 DriverMD = Driver.GetMetadata()
423 if not DriverMD.has_key('DCAP_CREATE'):
424 print 'Format driver %s does not support creation and piecewise writing.\nPlease select a format that does, such as GTiff (the default) or HFA (Erdas Imagine).' % format
425 sys.exit( 1 )
426
427 # Collect information on all the source files.
428 file_infos = names_to_fileinfos( names )
429
430 if ulx is None:
431 ulx = file_infos[0].ulx
432 uly = file_infos[0].uly
433 lrx = file_infos[0].lrx
434 lry = file_infos[0].lry
435
436 for fi in file_infos:
437 ulx = min(ulx, fi.ulx)
438 uly = max(uly, fi.uly)
439 lrx = max(lrx, fi.lrx)
440 lry = min(lry, fi.lry)
441
442 if psize_x is None:
443 psize_x = file_infos[0].geotransform[1]
444 psize_y = file_infos[0].geotransform[5]
445
446 if band_type is None:
447 band_type = file_infos[0].band_type
448
449 # Try opening as an existing file.
450 gdal.PushErrorHandler( 'CPLQuietErrorHandler' )
451 t_fh = gdal.Open( out_file, gdal.GA_ReadOnly )
452 gdal.PopErrorHandler()
453
454 # Create output file if it does not already exist.
455 if t_fh is None:
456 geotransform = [ulx, psize_x, 0, uly, 0, psize_y]
457
458 xsize = int((lrx - ulx) / geotransform[1] + 0.5)
459 ysize = int((lry - uly) / geotransform[5] + 0.5)
460
461 if separate != 0:
462 bands = len(file_infos)
463 else:
464 bands = file_infos[0].bands
465
466 t_fh = Driver.Create( out_file, xsize, ysize, bands,
467 band_type, create_options )
468 if t_fh is None:
469 print 'Creation failed, terminating gdal_merge.'
470 sys.exit( 1 )
471
472 t_fh.SetGeoTransform( geotransform )
473 t_fh.SetProjection( file_infos[0].projection )
474
475 if copy_pct:
476 t_fh.GetRasterBand(1).SetRasterColorTable(file_infos[0].ct)
477 else:
478 if separate != 0:
479 bands = len(file_infos)
480 else:
481 bands = min(file_infos[0].bands,t_fh.RasterCount)
482
483 # Do we need to pre-initialize the whole mosaic file to some value?
484 if pre_init is not None:
485 for i in range(t_fh.RasterCount):
486 t_fh.GetRasterBand(i+1).Fill( pre_init )
487
488 # Copy data from source files into output file.
489 t_band = 1
490 for fi in file_infos:
491 if createonly != 0:
492 continue
493
494 if verbose != 0:
495 print
496 fi.report()
497
498 if separate == 0 :
499 for band in range(1, bands+1):
500 fi.copy_into( t_fh, band, band, nodata )
501 else:
502 fi.copy_into( t_fh, 1, t_band, nodata )
503 t_band = t_band+1
504
505 # Force file to be closed.
506 t_fh = None
507
写代码有好几年了，现在才深刻体会到软件设计模式、架构、文档、规范的重要性，反而感觉做工作时有些瞻前顾后，总想把代码的逻辑整的很清晰以提高可维护行和复用性，真是那个 阶段有哪个阶段的烦恼，呵呵！
1 #!/usr/bin/env python
2 ###############################################################################
3 # $Id: gdal_merge.py,v 1.25 2006/04/20 13:27:57 fwarmerdam Exp $
4 #
5 # Project: InSAR Peppers
6 # Purpose: Module to extract data from many rasters into one output.
7 # Author: Frank Warmerdam, warmerdam@pobox.com
8 #
9 ###############################################################################
10 # Copyright (c) 2000, Atlantis Scientific Inc. (www.atlsci.com)
11 #
12 # This library is free software; you can redistribute it and/or
13 # modify it under the terms of the GNU Library General Public
14 # License as published by the Free Software Foundation; either
15 # version 2 of the License, or (at your option) any later version.
16 #
17 # This library is distributed in the hope that it will be useful,
18 # but WITHOUT ANY WARRANTY; without even the implied warranty of
19 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
20 # Library General Public License for more details.
21 #
22 # You should have received a copy of the GNU Library General Public
23 # License along with this library; if not, write to the
24 # Free Software Foundation, Inc., 59 Temple Place - Suite 330,
25 # Boston, MA 02111-1307, USA.
26 ###############################################################################
27 #
28 # $Log: gdal_merge.py,v $
29 # Revision 1.25 2006/04/20 13:27:57 fwarmerdam
30 # Added error checks on Driver's Create support and success of Create.
31 #
32 # Revision 1.24 2006/01/26 23:40:39 fwarmerdam
33 # treat nodata as a float.
34 #
35 # Revision 1.23 2005/11/25 02:13:36 fwarmerdam
36 # Added --help-general.
37 #
38 # Revision 1.22 2005/11/16 18:30:49 fwarmerdam
39 # Fixed round off issue with output file size.
40 #
41 # Revision 1.21 2005/08/18 15:45:15 fwarmerdam
42 # Added the -createonly switch.
43 #
44 # Revision 1.20 2005/07/19 03:33:39 fwarmerdam
45 # removed left over global_list
46 #
47 # Revision 1.19 2005/06/23 19:51:51 fwarmerdam
48 # Fixed support for non-square pixels c/o Matt Giger
49 # http://bugzilla.remotesensing.org/show_bug.cgi?id=874
50 #
51 # Revision 1.18 2005/03/29 22:40:00 fwarmerdam
52 # Added -ot option.
53 #
54 # Revision 1.17 2005/02/23 18:29:07 fwarmerdam
55 # Accept "either spelling" of separate.
56 #
57 # Revision 1.16 2005/02/23 18:23:00 fwarmerdam
58 # Added -seperate to the usage message.
59 #
60 # Revision 1.15 2004/09/02 22:06:24 warmerda
61 # Added a bit of commandline error reporting.
62 #
63 # Revision 1.14 2004/08/23 15:05:27 warmerda
64 # Added projection setting for new files.
65 #
66 # Revision 1.13 2004/04/02 22:31:26 warmerda
67 # Use -of for format.
68 #
69 # Revision 1.12 2004/04/02 17:40:44 warmerda
70 # added GDALGeneralCmdLineProcessor() support
71 #
72 # Revision 1.11 2004/03/26 17:11:42 warmerda
73 # added -init
74 #
75 # Revision 1.10 2003/04/22 14:42:45 warmerda
76 # Don't import Numeric unless we need it.
77 #
78 # Revision 1.9 2003/04/22 13:30:05 warmerda
79 # Added -co flag.
80 #
81 # Revision 1.8 2003/03/07 16:26:39 warmerda
82 # fixed up for ungeoreferenced files, supress extra error
83 #
84 # Revision 1.7 2003/01/28 15:00:13 warmerda
85 # applied patch for multi-band support from Ken Boss
86 #
87 # Revision 1.6 2003/01/20 22:19:08 warmerda
88 # added nodata support
89 #
90 # Revision 1.5 2002/12/12 14:54:42 warmerda
91 # added the -pct flag to copy over a pct
92 #
93 # Revision 1.4 2002/12/12 14:48:12 warmerda
94 # removed broken options arg to gdal.Create()
95 #
96 # Revision 1.3 2002/04/03 21:12:05 warmerda
97 # added -separate flag for Gerald Buckmaster
98 #
99 # Revision 1.2 2000/11/29 20:36:18 warmerda
100 # allow output file to be preexisting
101 #
102 # Revision 1.1 2000/11/29 20:23:13 warmerda
103 # New
104 #
105 #
106
107 import gdal
108 import sys
109
110 verbose = 0
111
112
113 # =============================================================================
114 def raster_copy( s_fh, s_xoff, s_yoff, s_xsize, s_ysize, s_band_n,
115 t_fh, t_xoff, t_yoff, t_xsize, t_ysize, t_band_n,
116 nodata=None ):
117
118 if nodata is not None:
119 return raster_copy_with_nodata(
120 s_fh, s_xoff, s_yoff, s_xsize, s_ysize, s_band_n,
121 t_fh, t_xoff, t_yoff, t_xsize, t_ysize, t_band_n,
122 nodata )
123
124 if verbose != 0:
125 print 'Copy %d,%d,%d,%d to %d,%d,%d,%d.' \
126 % (s_xoff, s_yoff, s_xsize, s_ysize,
127 t_xoff, t_yoff, t_xsize, t_ysize )
128
129 s_band = s_fh.GetRasterBand( s_band_n )
130 t_band = t_fh.GetRasterBand( t_band_n )
131
132 data = s_band.ReadRaster( s_xoff, s_yoff, s_xsize, s_ysize,
133 t_xsize, t_ysize, t_band.DataType )
134 t_band.WriteRaster( t_xoff, t_yoff, t_xsize, t_ysize,
135 data, t_xsize, t_ysize, t_band.DataType )
136
137
138 return 0
139
140 # =============================================================================
141 def raster_copy_with_nodata( s_fh, s_xoff, s_yoff, s_xsize, s_ysize, s_band_n,
142 t_fh, t_xoff, t_yoff, t_xsize, t_ysize, t_band_n,
143 nodata ):
144
145 import Numeric
146
147 if verbose != 0:
148 print 'Copy %d,%d,%d,%d to %d,%d,%d,%d.' \
149 % (s_xoff, s_yoff, s_xsize, s_ysize,
150 t_xoff, t_yoff, t_xsize, t_ysize )
151
152 s_band = s_fh.GetRasterBand( s_band_n )
153 t_band = t_fh.GetRasterBand( t_band_n )
154
155 data_src = s_band.ReadAsArray( s_xoff, s_yoff, s_xsize, s_ysize,
156 t_xsize, t_ysize )
157 data_dst = t_band.ReadAsArray( t_xoff, t_yoff, t_xsize, t_ysize )
158
159 nodata_test = Numeric.equal(data_src,nodata)
160 to_write = Numeric.choose( nodata_test, (data_src, data_dst) )
161
162 t_band.WriteArray( to_write, t_xoff, t_yoff )
163
164 return 0
165
166 # =============================================================================
167 def names_to_fileinfos( names ):
168 """
169 Translate a list of GDAL filenames, into file_info objects.
170
171 names -- list of valid GDAL dataset names.
172
173 Returns a list of file_info objects. There may be less file_info objects
174 than names if some of the names could not be opened as GDAL files.
175 """
176
177 file_infos = []
178 for name in names:
179 fi = file_info()
180 if fi.init_from_name( name ) == 1:
181 file_infos.append( fi )
182
183 return file_infos
184
185 # *****************************************************************************
186 class file_info:
187 """A class holding information about a GDAL file."""
188
189 def init_from_name(self, filename):
190 """
191 Initialize file_info from filename
192
193 filename -- Name of file to read.
194
195 Returns 1 on success or 0 if the file can't be opened.
196 """
197 fh = gdal.Open( filename )
198 if fh is None:
199 return 0
200
201 self.filename = filename
202 self.bands = fh.RasterCount
203 self.xsize = fh.RasterXSize
204 self.ysize = fh.RasterYSize
205 self.band_type = fh.GetRasterBand(1).DataType
206 self.projection = fh.GetProjection()
207 self.geotransform = fh.GetGeoTransform()
208 self.ulx = self.geotransform[0]
209 self.uly = self.geotransform[3]
210 self.lrx = self.ulx + self.geotransform[1] * self.xsize
211 self.lry = self.uly + self.geotransform[5] * self.ysize
212
213 ct = fh.GetRasterBand(1).GetRasterColorTable()
214 if ct is not None:
215 self.ct = ct.Clone()
216 else:
217 self.ct = None
218
219 return 1
220
221 def report( self ):
222 print 'Filename: '+ self.filename
223 print 'File Size: %dx%dx%d' \
224 % (self.xsize, self.ysize, self.bands)
225 print 'Pixel Size: %f x %f' \
226 % (self.geotransform[1],self.geotransform[5])
227 print 'UL:(%f,%f) LR:(%f,%f)' \
228 % (self.ulx,self.uly,self.lrx,self.lry)
229
230 def copy_into( self, t_fh, s_band = 1, t_band = 1, nodata_arg=None ):
231 """
232 Copy this files image into target file.
233
234 This method will compute the overlap area of the file_info objects
235 file, and the target gdal.Dataset object, and copy the image data
236 for the common window area. It is assumed that the files are in
237 a compatible projection
no checking or warping is done. However,238 if the destination file is a different resolution, or different
239 image pixel type, the appropriate resampling and conversions will
240 be done (using normal GDAL promotion/demotion rules).
241
242 t_fh -- gdal.Dataset object for the file into which some or all
243 of this file may be copied.
244
245 Returns 1 on success (or if nothing needs to be copied), and zero one
246 failure.
247 """
248 t_geotransform = t_fh.GetGeoTransform()
249 t_ulx = t_geotransform[0]
250 t_uly = t_geotransform[3]
251 t_lrx = t_geotransform[0] + t_fh.RasterXSize * t_geotransform[1]
252 t_lry = t_geotransform[3] + t_fh.RasterYSize * t_geotransform[5]
253
254 # figure out intersection region
255 tgw_ulx = max(t_ulx,self.ulx)
256 tgw_lrx = min(t_lrx,self.lrx)
257 if t_geotransform[5] < 0:
258 tgw_uly = min(t_uly,self.uly)
259 tgw_lry = max(t_lry,self.lry)
260 else:
261 tgw_uly = max(t_uly,self.uly)
262 tgw_lry = min(t_lry,self.lry)
263
264 # do they even intersect?
265 if tgw_ulx >= tgw_lrx:
266 return 1
267 if t_geotransform[5] < 0 and tgw_uly <= tgw_lry:
268 return 1
269 if t_geotransform[5] > 0 and tgw_uly >= tgw_lry:
270 return 1
271
272 # compute target window in pixel coordinates.
273 tw_xoff = int((tgw_ulx - t_geotransform[0]) / t_geotransform[1] + 0.1)
274 tw_yoff = int((tgw_uly - t_geotransform[3]) / t_geotransform[5] + 0.1)
275 tw_xsize = int((tgw_lrx - t_geotransform[0])/t_geotransform[1] + 0.5) \
276 - tw_xoff
277 tw_ysize = int((tgw_lry - t_geotransform[3])/t_geotransform[5] + 0.5) \
278 - tw_yoff
279
280 if tw_xsize < 1 or tw_ysize < 1:
281 return 1
282
283 # Compute source window in pixel coordinates.
284 sw_xoff = int((tgw_ulx - self.geotransform[0]) / self.geotransform[1])
285 sw_yoff = int((tgw_uly - self.geotransform[3]) / self.geotransform[5])
286 sw_xsize = int((tgw_lrx - self.geotransform[0]) \
287 / self.geotransform[1] + 0.5) - sw_xoff
288 sw_ysize = int((tgw_lry - self.geotransform[3]) \
289 / self.geotransform[5] + 0.5) - sw_yoff
290
291 if sw_xsize < 1 or sw_ysize < 1:
292 return 1
293
294 # Open the source file, and copy the selected region.
295 s_fh = gdal.Open( self.filename )
296
297 return \
298 raster_copy( s_fh, sw_xoff, sw_yoff, sw_xsize, sw_ysize, s_band,
299 t_fh, tw_xoff, tw_yoff, tw_xsize, tw_ysize, t_band,
300 nodata_arg )
301
302
303 # =============================================================================
304 def Usage():
305 print 'Usage: gdal_merge.py [-o out_filename] [-of out_format] [-co NAME=VALUE]*'
306 print ' [-ps pixelsize_x pixelsize_y] [-separate] [-v] [-pct]'
307 print ' [-ul_lr ulx uly lrx lry] [-n nodata_value] [-init value]'
308 print ' [-ot datatype] [-createonly] input_files'
309 print ' [--help-general]'
310 print
311
312 # =============================================================================
313 #
314 # Program mainline.
315 #
316
317 if __name__ == '__main__':
318
319 names = []
320 format = 'GTiff'
321 out_file = 'out.tif'
322
323 ulx = None
324 psize_x = None
325 separate = 0
326 copy_pct = 0
327 nodata = None
328 create_options = []
329 pre_init = None
330 band_type = None
331 createonly = 0
332
333 gdal.AllRegister()
334 argv = gdal.GeneralCmdLineProcessor( sys.argv )
335 if argv is None:
336 sys.exit( 0 )
337
338 # Parse command line arguments.
339 i = 1
340 while i < len(argv):
341 arg = argv[i]
342
343 if arg == '-o':
344 i = i + 1
345 out_file = argv[i]
346
347 elif arg == '-v':
348 verbose = 1
349
350 elif arg == '-createonly':
351 createonly = 1
352
353 elif arg == '-separate':
354 separate = 1
355
356 elif arg == '-seperate':
357 separate = 1
358
359 elif arg == '-pct':
360 copy_pct = 1
361
362 elif arg == '-ot':
363 i = i + 1
364 band_type = gdal.GetDataTypeByName( argv[i] )
365 if band_type == gdal.GDT_Unknown:
366 print 'Unknown GDAL data type: ', argv[i]
367 sys.exit( 1 )
368
369 elif arg == '-init':
370 i = i + 1
371 pre_init = float(argv[i])
372
373 elif arg == '-n':
374 i = i + 1
375 nodata = float(argv[i])
376
377 elif arg == '-f':
378 # for backward compatibility.
379 i = i + 1
380 format = argv[i]
381
382 elif arg == '-of':
383 i = i + 1
384 format = argv[i]
385
386 elif arg == '-co':
387 i = i + 1
388 create_options.append( argv[i] )
389
390 elif arg == '-ps':
391 psize_x = float(argv[i+1])
392 psize_y = -1 * abs(float(argv[i+2]))
393 i = i + 2
394
395 elif arg == '-ul_lr':
396 ulx = float(argv[i+1])
397 uly = float(argv[i+2])
398 lrx = float(argv[i+3])
399 lry = float(argv[i+4])
400 i = i + 4
401
402 elif arg[:1] == '-':
403 print 'Unrecognised command option: ', arg
404 Usage()
405 sys.exit( 1 )
406
407 else:
408 names.append( arg )
409
410 i = i + 1
411
412 if len(names) == 0:
413 print 'No input files selected.'
414 Usage()
415 sys.exit( 1 )
416
417 Driver = gdal.GetDriverByName(format)
418 if Driver is None:
419 print 'Format driver %s not found, pick a supported driver.' % format
420 sys.exit( 1 )
421
422 DriverMD = Driver.GetMetadata()
423 if not DriverMD.has_key('DCAP_CREATE'):
424 print 'Format driver %s does not support creation and piecewise writing.\nPlease select a format that does, such as GTiff (the default) or HFA (Erdas Imagine).' % format
425 sys.exit( 1 )
426
427 # Collect information on all the source files.
428 file_infos = names_to_fileinfos( names )
429
430 if ulx is None:
431 ulx = file_infos[0].ulx
432 uly = file_infos[0].uly
433 lrx = file_infos[0].lrx
434 lry = file_infos[0].lry
435
436 for fi in file_infos:
437 ulx = min(ulx, fi.ulx)
438 uly = max(uly, fi.uly)
439 lrx = max(lrx, fi.lrx)
440 lry = min(lry, fi.lry)
441
442 if psize_x is None:
443 psize_x = file_infos[0].geotransform[1]
444 psize_y = file_infos[0].geotransform[5]
445
446 if band_type is None:
447 band_type = file_infos[0].band_type
448
449 # Try opening as an existing file.
450 gdal.PushErrorHandler( 'CPLQuietErrorHandler' )
451 t_fh = gdal.Open( out_file, gdal.GA_ReadOnly )
452 gdal.PopErrorHandler()
453
454 # Create output file if it does not already exist.
455 if t_fh is None:
456 geotransform = [ulx, psize_x, 0, uly, 0, psize_y]
457
458 xsize = int((lrx - ulx) / geotransform[1] + 0.5)
459 ysize = int((lry - uly) / geotransform[5] + 0.5)
460
461 if separate != 0:
462 bands = len(file_infos)
463 else:
464 bands = file_infos[0].bands
465
466 t_fh = Driver.Create( out_file, xsize, ysize, bands,
467 band_type, create_options )
468 if t_fh is None:
469 print 'Creation failed, terminating gdal_merge.'
470 sys.exit( 1 )
471
472 t_fh.SetGeoTransform( geotransform )
473 t_fh.SetProjection( file_infos[0].projection )
474
475 if copy_pct:
476 t_fh.GetRasterBand(1).SetRasterColorTable(file_infos[0].ct)
477 else:
478 if separate != 0:
479 bands = len(file_infos)
480 else:
481 bands = min(file_infos[0].bands,t_fh.RasterCount)
482
483 # Do we need to pre-initialize the whole mosaic file to some value?
484 if pre_init is not None:
485 for i in range(t_fh.RasterCount):
486 t_fh.GetRasterBand(i+1).Fill( pre_init )
487
488 # Copy data from source files into output file.
489 t_band = 1
490 for fi in file_infos:
491 if createonly != 0:
492 continue
493
494 if verbose != 0:
495 print
496 fi.report()
497
498 if separate == 0 :
499 for band in range(1, bands+1):
500 fi.copy_into( t_fh, band, band, nodata )
501 else:
502 fi.copy_into( t_fh, 1, t_band, nodata )
503 t_band = t_band+1
504
505 # Force file to be closed.
506 t_fh = None
507