Hot-keys on this page

r m x p   toggle line displays

j k   next/prev highlighted chunk

0   (zero) top of page

1   (one) first highlighted chunk

1

2

3

4

5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

22

23

24

25

26

27

28

29

30

31

32

33

34

35

36

37

38

39

40

41

42

43

44

45

46

47

48

49

50

51

52

53

54

55

56

57

58

59

60

61

62

63

64

65

66

67

68

69

70

71

72

73

74

75

76

77

78

79

80

81

82

83

84

85

86

87

88

89

90

91

92

93

94

95

96

97

98

99

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

292

293

294

295

296

297

298

299

300

301

302

303

304

305

306

307

308

309

310

311

312

313

314

315

316

317

318

319

320

321

322

323

324

325

326

327

328

329

330

331

332

333

334

335

336

337

338

339

340

341

342

343

344

345

346

347

348

349

350

351

352

353

354

355

356

357

358

359

360

361

362

363

364

365

366

367

368

369

370

371

372

373

374

375

376

377

378

379

380

381

382

383

384

385

386

387

388

389

390

391

392

393

394

395

396

397

398

399

400

401

402

403

404

405

406

407

408

409

410

411

412

413

414

415

416

417

418

419

420

421

422

423

424

425

426

427

428

429

430

431

432

433

434

435

436

437

438

439

440

441

442

443

444

445

446

447

448

449

450

451

452

453

454

455

456

457

458

459

460

461

462

463

464

465

466

467

468

469

470

471

472

473

474

475

476

477

478

479

480

481

482

483

484

485

486

487

488

489

490

491

492

493

494

495

496

497

498

499

500

501

502

503

504

505

506

507

508

509

510

511

512

513

514

515

516

517

518

519

520

521

522

523

524

525

526

527

528

529

530

531

532

533

534

535

536

537

538

539

540

541

542

543

544

545

546

547

548

549

550

551

552

553

554

555

556

557

558

559

560

561

562

563

564

565

566

567

568

569

570

571

572

573

574

575

576

577

578

579

580

581

582

583

584

585

# -*- coding: utf-8 -*- 

""" 

The obspy.segy test suite. 

""" 

 

from StringIO import StringIO 

from obspy.core.util import NamedTemporaryFile 

from obspy.segy.header import DATA_SAMPLE_FORMAT_PACK_FUNCTIONS, \ 

    DATA_SAMPLE_FORMAT_UNPACK_FUNCTIONS 

from obspy.segy.segy import SEGYBinaryFileHeader, SEGYTraceHeader, SEGYFile, \ 

    readSEGY 

from obspy.segy.tests.header import FILES, DTYPES 

import numpy as np 

import os 

import unittest 

 

 

class SEGYTestCase(unittest.TestCase): 

    """ 

    Test cases for SEG Y reading and writing.. 

    """ 

    def setUp(self): 

        # directory where the test files are located 

        self.dir = os.path.dirname(__file__) 

        self.path = os.path.join(self.dir, 'data') 

        # All the files and information about them. These files will be used in 

        # most tests. data_sample_enc is the encoding of the data value and 

        # sample_size the size in bytes of these samples. 

        self.files = FILES 

        self.dtypes = DTYPES 

 

    def test_unpackSEGYData(self): 

        """ 

        Tests the unpacking of various SEG Y files. 

        """ 

        for file, attribs in self.files.iteritems(): 

            data_format = attribs['data_sample_enc'] 

            endian = attribs['endian'] 

            count = attribs['sample_count'] 

            file = os.path.join(self.path, file) 

            # Use the with statement to make sure the file closes. 

            with open(file, 'rb') as f: 

                # Jump to the beginning of the data. 

                f.seek(3840) 

                # Unpack the data. 

                data = DATA_SAMPLE_FORMAT_UNPACK_FUNCTIONS[data_format](f, 

                                count, endian) 

            # Check the dtype of the data. 

            self.assertEqual(data.dtype, self.dtypes[data_format]) 

            # Proven data values, read with Madagascar. 

            correct_data = np.load(file + '.npy').ravel() 

            # Compare both. 

            np.testing.assert_array_equal(correct_data, data) 

 

    def test_packSEGYData(self): 

        """ 

        Tests the packing of various SEG Y files. 

        """ 

        # Loop over all files. 

        for file, attribs in self.files.iteritems(): 

            # Get some attributes. 

            data_format = attribs['data_sample_enc'] 

            endian = attribs['endian'] 

            count = attribs['sample_count'] 

            size = attribs['sample_size'] 

            non_normalized_samples = attribs['non_normalized_samples'] 

            dtype = self.dtypes[data_format] 

            file = os.path.join(self.path, file) 

            # Load the data. This data has previously been unpacked by 

            # Madagascar. 

            data = np.load(file + '.npy').ravel() 

            data = np.require(data, dtype) 

            # Load the packed data. 

            with open(file, 'rb') as f: 

                # Jump to the beginning of the data. 

                f.seek(3200 + 400 + 240) 

                packed_data = f.read(count * size) 

            # The pack functions all write to file objects. 

            f = StringIO() 

            # Pack the data. 

            DATA_SAMPLE_FORMAT_PACK_FUNCTIONS[data_format](f, data, endian) 

            # Read again.0. 

            f.seek(0, 0) 

            new_packed_data = f.read() 

            # Check the length. 

            self.assertEqual(len(packed_data), len(new_packed_data)) 

            if len(non_normalized_samples) == 0: 

                # The packed data should be totally identical. 

                self.assertEqual(packed_data, new_packed_data) 

            else: 

                # Some test files contain non normalized IBM floating point 

                # data. These cannot be reproduced exactly. 

                # Just a sanity check to be sure it is only IBM floating point 

                # data that does not work completely. 

                self.assertEqual(data_format, 1) 

 

                # Read the data as uint8 to be able to directly access the 

                # different bytes. 

                # Original data. 

                packed_data = np.fromstring(packed_data, 'uint8') 

                # Newly written. 

                new_packed_data = np.fromstring(new_packed_data, 'uint8') 

 

                # Figure out the non normalized fractions in the original data 

                # because these cannot be compared directly. 

                # Get the position of the first byte of the fraction depending 

                # on the endianness. 

                if endian == '>': 

                    start = 1 

                else: 

                    start = 2 

                # The first byte of the fraction. 

                first_fraction_byte_old = packed_data[start::4] 

                # First get all zeros in the original data because zeros have 

                # to be treated differently. 

                zeros = np.where(data == 0)[0] 

                # Create a copy and set the zeros to a high number to be able 

                # to find all non normalized numbers. 

                fraction_copy = first_fraction_byte_old.copy() 

                fraction_copy[zeros] = 255 

                # Normalized numbers will have no zeros in the first 4 bit of 

                # the fraction. This means that the most significant byte of 

                # the fraction has to be at least 16 for it to be normalized. 

                non_normalized = np.where(fraction_copy < 16)[0] 

 

                # Sanity check if the file data and the calculated data are the 

                # same. 

                np.testing.assert_array_equal(non_normalized, 

                                              np.array(non_normalized_samples)) 

 

                # Test all other parts of the packed data. Set dtype to int32 

                # to get 4 byte numbers. 

                packed_data_copy = packed_data.copy() 

                new_packed_data_copy = new_packed_data.copy() 

                packed_data_copy.dtype = 'int32' 

                new_packed_data_copy.dtype = 'int32' 

                # Equalize the non normalized parts. 

                packed_data_copy[non_normalized] = \ 

                        new_packed_data_copy[non_normalized] 

                np.testing.assert_array_equal(packed_data_copy, 

                                              new_packed_data_copy) 

 

                # Now check the non normalized parts if they are almost the 

                # same. 

                data = data[non_normalized] 

                # Unpack the data again. 

                new_packed_data.dtype = 'int32' 

                new_packed_data = new_packed_data[non_normalized] 

                length = len(new_packed_data) 

                f = StringIO() 

                f.write(new_packed_data.tostring()) 

                f.seek(0, 0) 

                new_data = DATA_SAMPLE_FORMAT_UNPACK_FUNCTIONS[1](f, 

                                        length, endian) 

                f.close() 

                packed_data.dtype = 'int32' 

                packed_data = packed_data[non_normalized] 

                length = len(packed_data) 

                f = StringIO() 

                f.write(packed_data.tostring()) 

                f.seek(0, 0) 

                old_data = DATA_SAMPLE_FORMAT_UNPACK_FUNCTIONS[1](f, 

                                        length, endian) 

                f.close() 

                # This works because the normalized and the non normalized IBM 

                # floating point numbers will be close enough for the internal 

                # IEEE representation to be identical. 

                np.testing.assert_array_equal(data, new_data) 

                np.testing.assert_array_equal(data, old_data) 

 

    def test_packAndUnpackIBMFloat(self): 

        """ 

        Packing and unpacking IBM floating points might yield some inaccuracies 

        due to floating point rounding errors. 

        This test tests a large number of random floating point numbers. 

        """ 

        # Some random seeds. 

        seeds = [1234, 592, 459482, 6901, 0, 7083, 68349] 

        endians = ['<', '>'] 

        # Loop over all combinations. 

        for seed in seeds: 

            # Generate 50000 random floats from -10000 to +10000. 

            np.random.seed(seed) 

            data = 200000.0 * np.random.ranf(50000) - 100000.0 

            # Convert to float64 in case native floats are different to be 

            # able to utilize double precision. 

            data = np.require(data, 'float64') 

            # Loop over little and big endian. 

            for endian in endians: 

                # Pack. 

                f = StringIO() 

                DATA_SAMPLE_FORMAT_PACK_FUNCTIONS[1](f, data, endian) 

                # Jump to beginning and read again. 

                f.seek(0, 0) 

                new_data = DATA_SAMPLE_FORMAT_UNPACK_FUNCTIONS[1](f, 

                                        len(data), endian) 

                f.close() 

                # A relative tolerance of 1E-6 is considered good enough. 

                rms1 = rms(data, new_data) 

                self.assertEqual(True, rms1 < 1E-6) 

 

    def test_packAndUnpackVerySmallIBMFloats(self): 

        """ 

        The same test as test_packAndUnpackIBMFloat just for small numbers 

        because they might suffer more from the inaccuracies. 

        """ 

        # Some random seeds. 

        seeds = [123, 1592, 4482, 601, 1, 783, 6849] 

        endians = ['<', '>'] 

        # Loop over all combinations. 

        for seed in seeds: 

            # Generate 50000 random floats from -10000 to +10000. 

            np.random.seed(seed) 

            data = 1E-5 * np.random.ranf(50000) 

            # Convert to float64 in case native floats are different to be 

            # able to utilize double precision. 

            data = np.require(data, 'float64') 

            # Loop over little and big endian. 

            for endian in endians: 

                # Pack. 

                f = StringIO() 

                DATA_SAMPLE_FORMAT_PACK_FUNCTIONS[1](f, data, endian) 

                # Jump to beginning and read again. 

                f.seek(0, 0) 

                new_data = DATA_SAMPLE_FORMAT_UNPACK_FUNCTIONS[1](f, 

                                        len(data), endian) 

                f.close() 

                # A relative tolerance of 1E-6 is considered good enough. 

                rms1 = rms(data, new_data) 

                self.assertEqual(True, rms1 < 1E-6) 

 

    def test_packAndUnpackIBMSpecialCases(self): 

        """ 

        Tests the packing and unpacking of several powers of 16 which are 

        problematic because they need separate handling in the algorithm. 

        """ 

        endians = ['>', '<'] 

        # Create the first 10 powers of 16. 

        data = [] 

        for i in xrange(10): 

            data.append(16 ** i) 

            data.append(-16 ** i) 

        data = np.array(data) 

        # Convert to float64 in case native floats are different to be 

        # able to utilize double precision. 

        data = np.require(data, 'float64') 

        # Loop over little and big endian. 

        for endian in endians: 

            # Pack. 

            f = StringIO() 

            DATA_SAMPLE_FORMAT_PACK_FUNCTIONS[1](f, data, endian) 

            # Jump to beginning and read again. 

            f.seek(0, 0) 

            new_data = DATA_SAMPLE_FORMAT_UNPACK_FUNCTIONS[1](f, 

                                    len(data), endian) 

            f.close() 

            # Test both. 

            np.testing.assert_array_equal(new_data, data) 

 

    def test_readAndWriteBinaryFileHeader(self): 

        """ 

        Reading and writing should not change the binary file header. 

        """ 

        for file, attribs in self.files.iteritems(): 

            endian = attribs['endian'] 

            file = os.path.join(self.path, file) 

            # Read the file. 

            with open(file, 'rb') as f: 

                f.seek(3200) 

                org_header = f.read(400) 

            header = SEGYBinaryFileHeader(header=org_header, endian=endian) 

            # The header writes to a file like object. 

            new_header = StringIO() 

            header.write(new_header) 

            new_header.seek(0, 0) 

            new_header = new_header.read() 

            # Assert the correct length. 

            self.assertEqual(len(new_header), 400) 

            # Assert the actual header. 

            self.assertEqual(org_header, new_header) 

 

    def test_readAndWriteTextualFileHeader(self): 

        """ 

        Reading and writing should not change the textual file header. 

        """ 

        for file, attribs in self.files.iteritems(): 

            endian = attribs['endian'] 

            header_enc = attribs['textual_header_enc'] 

            file = os.path.join(self.path, file) 

            # Read the file. 

            f = open(file, 'rb') 

            org_header = f.read(3200) 

            f.seek(0, 0) 

            # Initialize an empty SEGY object and set certain attributes. 

            segy = SEGYFile() 

            segy.endian = endian 

            segy.file = f 

            segy.textual_header_encoding = None 

            # Read the textual header. 

            segy._readTextualHeader() 

            # Assert the encoding and compare with known values. 

            self.assertEqual(segy.textual_header_encoding, header_enc) 

            # Close the file. 

            f.close() 

            # The header writes to a file like object. 

            new_header = StringIO() 

            segy._writeTextualHeader(new_header) 

            new_header.seek(0, 0) 

            new_header = new_header.read() 

            # Assert the correct length. 

            self.assertEqual(len(new_header), 3200) 

            # Assert the actual header. 

            self.assertEqual(org_header, new_header) 

 

    def test_readAndWriteTraceHeader(self): 

        """ 

        Reading and writing should not change the trace header. 

        """ 

        for file, attribs in self.files.iteritems(): 

            endian = attribs['endian'] 

            file = os.path.join(self.path, file) 

            # Read the file. 

            with open(file, 'rb') as f: 

                f.seek(3600) 

                org_header = f.read(240) 

            header = SEGYTraceHeader(header=org_header, endian=endian) 

            # The header writes to a file like object. 

            new_header = StringIO() 

            header.write(new_header) 

            new_header.seek(0, 0) 

            new_header = new_header.read() 

            # Assert the correct length. 

            self.assertEqual(len(new_header), 240) 

            # Assert the actual header. 

            self.assertEqual(org_header, new_header) 

 

    def test_readAndWriteSEGY(self, headonly=False): 

        """ 

        Reading and writing again should not change a file. 

        """ 

        for file, attribs in self.files.iteritems(): 

            file = os.path.join(self.path, file) 

            non_normalized_samples = attribs['non_normalized_samples'] 

            # Read the file. 

            with open(file, 'rb') as f: 

                org_data = f.read() 

            segy_file = readSEGY(file, headonly=headonly) 

            out_file = NamedTemporaryFile().name 

            segy_file.write(out_file) 

            # Read the new file again. 

            with open(out_file, 'rb') as f: 

                new_data = f.read() 

            os.remove(out_file) 

            # The two files should have the same length. 

            self.assertEqual(len(org_data), len(new_data)) 

            # Replace the not normalized samples. The not normalized 

            # samples are already tested in test_packSEGYData and therefore not 

            # tested again here. 

            if len(non_normalized_samples) != 0: 

                # Convert to 4 byte integers. Any 4 byte numbers work. 

                org_data = np.fromstring(org_data, 'int32') 

                new_data = np.fromstring(new_data, 'int32') 

                # Skip the header (4*960 bytes) and replace the non normalized 

                # data samples. 

                org_data[960:][non_normalized_samples] = \ 

                        new_data[960:][non_normalized_samples] 

                # Create strings again. 

                org_data = org_data.tostring() 

                new_data = new_data.tostring() 

            # Always write the SEGY File revision number! 

            #org_data[3500:3502] = new_data[3500:3502] 

            # Test the identity without the SEGY revision number 

            self.assertEqual(org_data[:3500], new_data[:3500]) 

            self.assertEqual(org_data[3502:], new_data[3502:]) 

 

    def test_readAndWriteSEGY_headonly(self): 

        """ 

        Reading with headonly=True and writing again should not change a file. 

        """ 

        self.test_readAndWriteSEGY(headonly=True) 

 

    def test_unpackBinaryFileHeader(self): 

        """ 

        Compares some values of the binary header with values read with 

        SeisView 2 by the DMNG. 

        """ 

        file = os.path.join(self.path, '1.sgy_first_trace') 

        segy = readSEGY(file) 

        header = segy.binary_file_header 

        # Compare the values. 

        self.assertEqual(header.job_identification_number, 0) 

        self.assertEqual(header.line_number, 0) 

        self.assertEqual(header.reel_number, 0) 

        self.assertEqual(header.number_of_data_traces_per_ensemble, 24) 

        self.assertEqual(header.number_of_auxiliary_traces_per_ensemble, 0) 

        self.assertEqual(header.sample_interval_in_microseconds, 250) 

        self.assertEqual( \ 

            header.sample_interval_in_microseconds_of_original_field_recording, 

                         250) 

        self.assertEqual(header.number_of_samples_per_data_trace, 8000) 

        self.assertEqual( \ 

          header.number_of_samples_per_data_trace_for_original_field_recording, 

                         8000) 

        self.assertEqual(header.data_sample_format_code, 2) 

        self.assertEqual(header.ensemble_fold, 0) 

        self.assertEqual(header.trace_sorting_code, 1) 

        self.assertEqual(header.vertical_sum_code, 0) 

        self.assertEqual(header.sweep_frequency_at_start, 0) 

        self.assertEqual(header.sweep_frequency_at_end, 0) 

        self.assertEqual(header.sweep_length, 0) 

        self.assertEqual(header.sweep_type_code, 0) 

        self.assertEqual(header.trace_number_of_sweep_channel, 0) 

        self.assertEqual(header.sweep_trace_taper_length_in_ms_at_start, 0) 

        self.assertEqual(header.sweep_trace_taper_length_in_ms_at_end, 0) 

        self.assertEqual(header.taper_type, 0) 

        self.assertEqual(header.correlated_data_traces, 0) 

        self.assertEqual(header.binary_gain_recovered, 0) 

        self.assertEqual(header.amplitude_recovery_method, 0) 

        self.assertEqual(header.measurement_system, 0) 

        self.assertEqual(header.impulse_signal_polarity, 0) 

        self.assertEqual(header.vibratory_polarity_code, 0) 

        self.assertEqual( \ 

             header.number_of_3200_byte_ext_file_header_records_following, 

                         0) 

 

    def test_unpackTraceHeader(self): 

        """ 

        Compares some values of the first trace header with values read with 

        SeisView 2 by the DMNG. 

        """ 

        file = os.path.join(self.path, '1.sgy_first_trace') 

        segy = readSEGY(file) 

        header = segy.traces[0].header 

        # Compare the values. 

        self.assertEqual(header.trace_sequence_number_within_line, 0) 

        self.assertEqual(header.trace_sequence_number_within_segy_file, 0) 

        self.assertEqual(header.original_field_record_number, 1) 

        self.assertEqual(header.trace_number_within_the_original_field_record, 

                        1) 

        self.assertEqual(header.energy_source_point_number, 0) 

        self.assertEqual(header.ensemble_number, 0) 

        self.assertEqual(header.trace_number_within_the_ensemble, 0) 

        self.assertEqual(header.trace_identification_code, 1) 

        self.assertEqual( \ 

            header.number_of_vertically_summed_traces_yielding_this_trace, 

                         5) 

        self.assertEqual( \ 

            header.number_of_horizontally_stacked_traces_yielding_this_trace, 

                         0) 

        self.assertEqual(header.data_use, 0) 

        self.assertEqual(getattr(header, 'distance_from_center_of_the_' + \ 

            'source_point_to_the_center_of_the_receiver_group'), 0) 

        self.assertEqual(header.receiver_group_elevation, 0) 

        self.assertEqual(header.surface_elevation_at_source, 0) 

        self.assertEqual(header.source_depth_below_surface, 0) 

        self.assertEqual(header.datum_elevation_at_receiver_group, 0) 

        self.assertEqual(header.datum_elevation_at_source, 0) 

        self.assertEqual(header.water_depth_at_source, 0) 

        self.assertEqual(header.water_depth_at_group, 0) 

        self.assertEqual( \ 

            header.scalar_to_be_applied_to_all_elevations_and_depths, -100) 

        self.assertEqual(header.scalar_to_be_applied_to_all_coordinates, -100) 

        self.assertEqual(header.source_coordinate_x, 0) 

        self.assertEqual(header.source_coordinate_y, 0) 

        self.assertEqual(header.group_coordinate_x, 300) 

        self.assertEqual(header.group_coordinate_y, 0) 

        self.assertEqual(header.coordinate_units, 0) 

        self.assertEqual(header.weathering_velocity, 0) 

        self.assertEqual(header.subweathering_velocity, 0) 

        self.assertEqual(header.uphole_time_at_source_in_ms, 0) 

        self.assertEqual(header.uphole_time_at_group_in_ms, 0) 

        self.assertEqual(header.source_static_correction_in_ms, 0) 

        self.assertEqual(header.group_static_correction_in_ms, 0) 

        self.assertEqual(header.total_static_applied_in_ms, 0) 

        self.assertEqual(header.lag_time_A, 0) 

        self.assertEqual(header.lag_time_B, 0) 

        self.assertEqual(header.delay_recording_time, -100) 

        self.assertEqual(header.mute_time_start_time_in_ms, 0) 

        self.assertEqual(header.mute_time_end_time_in_ms, 0) 

        self.assertEqual(header.number_of_samples_in_this_trace, 8000) 

        self.assertEqual(header.sample_interval_in_ms_for_this_trace, 250) 

        self.assertEqual(header.gain_type_of_field_instruments, 0) 

        self.assertEqual(header.instrument_gain_constant, 24) 

        self.assertEqual(header.instrument_early_or_initial_gain, 0) 

        self.assertEqual(header.correlated, 0) 

        self.assertEqual(header.sweep_frequency_at_start, 0) 

        self.assertEqual(header.sweep_frequency_at_end, 0) 

        self.assertEqual(header.sweep_length_in_ms, 0) 

        self.assertEqual(header.sweep_type, 0) 

        self.assertEqual(header.sweep_trace_taper_length_at_start_in_ms, 0) 

        self.assertEqual(header.sweep_trace_taper_length_at_end_in_ms, 0) 

        self.assertEqual(header.taper_type, 0) 

        self.assertEqual(header.alias_filter_frequency, 1666) 

        self.assertEqual(header.alias_filter_slope, 0) 

        self.assertEqual(header.notch_filter_frequency, 0) 

        self.assertEqual(header.notch_filter_slope, 0) 

        self.assertEqual(header.low_cut_frequency, 0) 

        self.assertEqual(header.high_cut_frequency, 0) 

        self.assertEqual(header.low_cut_slope, 0) 

        self.assertEqual(header.high_cut_slope, 0) 

        self.assertEqual(header.year_data_recorded, 2005) 

        self.assertEqual(header.day_of_year, 353) 

        self.assertEqual(header.hour_of_day, 15) 

        self.assertEqual(header.minute_of_hour, 7) 

        self.assertEqual(header.second_of_minute, 54) 

        self.assertEqual(header.time_basis_code, 0) 

        self.assertEqual(header.trace_weighting_factor, 0) 

        self.assertEqual( \ 

            header.geophone_group_number_of_roll_switch_position_one, 2) 

        self.assertEqual(header.geophone_group_number_of_trace_number_one, 2) 

        self.assertEqual(header.geophone_group_number_of_last_trace, 0) 

        self.assertEqual(header.gap_size, 0) 

        self.assertEqual(header.over_travel_associated_with_taper, 0) 

        self.assertEqual( \ 

            header.x_coordinate_of_ensemble_position_of_this_trace, 0) 

        self.assertEqual( \ 

            header.y_coordinate_of_ensemble_position_of_this_trace, 0) 

        self.assertEqual( \ 

            header.for_3d_poststack_data_this_field_is_for_in_line_number, 0) 

        self.assertEqual( \ 

            header.for_3d_poststack_data_this_field_is_for_cross_line_number, 

                         0) 

        self.assertEqual(header.shotpoint_number, 0) 

        self.assertEqual( \ 

            header.scalar_to_be_applied_to_the_shotpoint_number, 0) 

        self.assertEqual(header.trace_value_measurement_unit, 0) 

        self.assertEqual(header.transduction_constant_mantissa, 0) 

        self.assertEqual(header.transduction_constant_exponent, 0) 

        self.assertEqual(header.transduction_units, 0) 

        self.assertEqual(header.device_trace_identifier, 0) 

        self.assertEqual(header.scalar_to_be_applied_to_times, 0) 

        self.assertEqual(header.source_type_orientation, 0) 

        self.assertEqual(header.source_energy_direction_mantissa, 0) 

        self.assertEqual(header.source_energy_direction_exponent, 0) 

        self.assertEqual(header.source_measurement_mantissa, 0) 

        self.assertEqual(header.source_measurement_exponent, 0) 

        self.assertEqual(header.source_measurement_unit, 0) 

 

    def test_readStringIO(self): 

        """ 

        Tests reading from StringIO instances. 

        """ 

        # 1 

        file = os.path.join(self.path, 'example.y_first_trace') 

        data = open(file, 'rb').read() 

        st = readSEGY(StringIO(data)) 

        self.assertEqual(len(st.traces[0].data), 500) 

        # 2 

        file = os.path.join(self.path, 'ld0042_file_00018.sgy_first_trace') 

        data = open(file, 'rb').read() 

        st = readSEGY(StringIO(data)) 

        self.assertEqual(len(st.traces[0].data), 2050) 

        # 3 

        file = os.path.join(self.path, '1.sgy_first_trace') 

        data = open(file, 'rb').read() 

        st = readSEGY(StringIO(data)) 

        self.assertEqual(len(st.traces[0].data), 8000) 

        # 4 

        file = os.path.join(self.path, '00001034.sgy_first_trace') 

        data = open(file, 'rb').read() 

        st = readSEGY(StringIO(data)) 

        self.assertEqual(len(st.traces[0].data), 2001) 

        # 5 

        file = os.path.join(self.path, 'planes.segy_first_trace') 

        data = open(file, 'rb').read() 

        st = readSEGY(StringIO(data)) 

        self.assertEqual(len(st.traces[0].data), 512) 

 

 

def rms(x, y): 

    """ 

    Normalized RMS 

 

    Taken from the mtspec library: 

    https://github.com/krischer/mtspec 

    """ 

    return np.sqrt(((x - y) ** 2).mean() / (x ** 2).mean()) 

 

 

def suite(): 

    return unittest.makeSuite(SEGYTestCase, 'test') 

 

 

if __name__ == '__main__': 

    unittest.main(defaultTest='suite')