def test_writingUsingCore(self): """ Tests the writing of SEGY rev1 files using obspy.core. It just compares the output of writing using obspy.core with the output of writing the files using the internal SEGY object which is thoroughly tested in obspy.segy.tests.test_segy. """ for file, _ in self.files.iteritems(): file = os.path.join(self.path, file) # Read the file with the internal SEGY representation. segy_file = readSEGYInternal(file) # Read again using core. st = readSEGY(file) # Create two temporary files to write to. with NamedTemporaryFile() as tf1: out_file1 = tf1.name with NamedTemporaryFile() as tf2: out_file2 = tf2.name # Write twice. segy_file.write(out_file1) writeSEGY(st, out_file2) # Read and delete files. with open(out_file1, 'rb') as f1: data1 = f1.read() with open(out_file2, 'rb') as f2: data2 = f2.read() # Test if they are equal. self.assertEqual(data1[3200:3600], data2[3200:3600])
def test_readingAndWritingDifferentDataEncodings(self): """ Writes and reads different data encodings and checks if the data remains the same. """ # The file uses IBM data encoding. file = os.path.join(self.path, 'ld0042_file_00018.sgy_first_trace') st = readSEGY(file) data = st[0].data # All working encodings with corresponding dtypes. encodings = {1: 'float32', 2: 'int32', 3: 'int16', 5: 'float32'} with NamedTemporaryFile() as tf: out_file = tf.name # Loop over all encodings. for data_encoding, dtype in encodings.iteritems(): this_data = np.require(data.copy(), dtype) st[0].data = this_data writeSEGY(st, out_file, data_encoding=data_encoding) # Read again and compare data. this_stream = readSEGY(out_file) # Both should now be equal. Usually converting from IBM to IEEE # floating point numbers might result in small rouning errors # but in this case it seems to work. Might be different on # different computers. np.testing.assert_array_equal(this_data, this_stream[0].data)
def test_largeSampleRateIntervalRaises(self): """ SEG Y supports a sample interval from 1 to 65535 microseconds in steps of 1 microsecond. Larger intervals cannot be supported due to the definition of the SEG Y format. Therefore the smallest possible sampling rate is ~ 15.26 Hz. """ outfile = NamedTemporaryFile().name # Test for SEG Y. file = os.path.join(self.path, '1.sgy_first_trace') segy = readSEGY(file) # Set the largest possible delta value which should just work. segy[0].stats.delta = 0.065535 writeSEGY(segy, outfile) os.remove(outfile) # Slightly larger should raise. segy[0].stats.delta = 0.065536 self.assertRaises(SEGYSampleIntervalError, writeSEGY, segy, outfile) # Same for SU. file = os.path.join(self.path, '1.su_first_trace') su = readSU(file) # Set the largest possible delta value which should just work. su[0].stats.delta = 0.065535 writeSU(su, outfile) os.remove(outfile) # Slightly larger should raise. su[0].stats.delta = 0.065536 self.assertRaises(SEGYSampleIntervalError, writeSU, su, outfile)
def test_writingUsingCore(self): """ Tests the writing of SEGY rev1 files using obspy.core. It just compares the output of writing using obspy.core with the output of writing the files using the internal SEGY object which is thoroughly tested in obspy.segy.tests.test_segy. """ for file, _ in self.files.iteritems(): file = os.path.join(self.path, file) # Read the file with the internal SEGY representation. segy_file = readSEGYInternal(file) # Read again using core. st = readSEGY(file) # Create two temporary files to write to. out_file1 = NamedTemporaryFile().name out_file2 = NamedTemporaryFile().name # Write twice. segy_file.write(out_file1) writeSEGY(st, out_file2) # Read and delete files. with open(out_file1, 'rb') as f1: data1 = f1.read() with open(out_file2, 'rb') as f2: data2 = f2.read() os.remove(out_file1) os.remove(out_file2) # Test if they are equal. self.assertEqual(data1[3200:3600], data2[3200:3600])
def test_readingAndWritingDifferentDataEncodings(self): """ Writes and reads different data encodings and checks if the data remains the same. """ # The file uses IBM data encoding. file = os.path.join(self.path, 'ld0042_file_00018.sgy_first_trace') st = readSEGY(file) data = st[0].data # All working encodings with corresponding dtypes. encodings = {1: 'float32', 2: 'int32', 3: 'int16', 5: 'float32'} out_file = NamedTemporaryFile().name # Loop over all encodings. for data_encoding, dtype in encodings.iteritems(): this_data = np.require(data.copy(), dtype) st[0].data = this_data writeSEGY(st, out_file, data_encoding=data_encoding) # Read again and compare data. this_stream = readSEGY(out_file) os.remove(out_file) # Both should now be equal. Usually converting from IBM to IEEE # floating point numbers might result in small rouning errors but # in this case it seems to work. Might be different on different # computers. np.testing.assert_array_equal(this_data, this_stream[0].data)
def test_largeSampleRateIntervalRaises(self): """ SEG Y supports a sample interval from 1 to 65535 microseconds in steps of 1 microsecond. Larger intervals cannot be supported due to the definition of the SEG Y format. Therefore the smallest possible sampling rate is ~ 15.26 Hz. """ with NamedTemporaryFile() as tf: outfile = tf.name # Test for SEG Y. file = os.path.join(self.path, '1.sgy_first_trace') segy = readSEGY(file) # Set the largest possible delta value which should just work. segy[0].stats.delta = 0.065535 writeSEGY(segy, outfile) # Slightly larger should raise. segy[0].stats.delta = 0.065536 self.assertRaises(SEGYSampleIntervalError, writeSEGY, segy, outfile) # Same for SU. file = os.path.join(self.path, '1.su_first_trace') su = readSU(file) # Set the largest possible delta value which should just work. su[0].stats.delta = 0.065535 writeSU(su, outfile) # Slightly larger should raise. su[0].stats.delta = 0.065536 self.assertRaises(SEGYSampleIntervalError, writeSU, su, outfile)
def test_writingStarttimeTimestamp0(self): """ If the starttime of the Trace is UTCDateTime(0) it will be interpreted as a missing starttime is not written. Test if this holds True. """ file = os.path.join(self.path, '1.sgy_first_trace') # This file has a set date! with open(file, 'rb') as f: f.seek(3600 + 156, 0) date_time = f.read(10) year, julday, hour, minute, second = unpack('>5h', date_time) self.assertEqual([ year == 2005, julday == 353, hour == 15, minute == 7, second == 54 ], 5 * [True]) # Read and set zero time. segy = readSEGY(file) segy[0].stats.starttime = UTCDateTime(0) outfile = NamedTemporaryFile().name writeSEGY(segy, outfile) # Check the new date. with open(outfile, 'rb') as f: f.seek(3600 + 156, 0) date_time = f.read(10) os.remove(outfile) year, julday, hour, minute, second = unpack('>5h', date_time) self.assertEqual( [year == 0, julday == 0, hour == 0, minute == 0, second == 0], 5 * [True]) # The same for SU. file = os.path.join(self.path, '1.su_first_trace') # This file has a set date! with open(file, 'rb') as f: f.seek(156, 0) date_time = f.read(10) year, julday, hour, minute, second = unpack('<5h', date_time) self.assertEqual([ year == 2005, julday == 353, hour == 15, minute == 7, second == 54 ], 5 * [True]) # Read and set zero time. su = readSU(file) su[0].stats.starttime = UTCDateTime(0) outfile = NamedTemporaryFile().name writeSU(su, outfile) # Check the new date. with open(outfile, 'rb') as f: f.seek(156, 0) date_time = f.read(10) os.remove(outfile) year, julday, hour, minute, second = unpack('<5h', date_time) self.assertEqual( [year == 0, julday == 0, hour == 0, minute == 0, second == 0], 5 * [True])
def test_writingNewSamplingRate(self): """ Setting a new sample rate works. """ file = os.path.join(self.path, '1.sgy_first_trace') segy = readSEGY(file) segy[0].stats.sampling_rate = 20 with NamedTemporaryFile() as tf: outfile = tf.name writeSEGY(segy, outfile) new_segy = readSEGY(outfile) self.assertEqual(new_segy[0].stats.sampling_rate, 20) # The same with the Seismic Unix file. file = os.path.join(self.path, '1.su_first_trace') _su = readSU(file)
def test_writingNewSamplingRate(self): """ Setting a new sample rate works. """ file = os.path.join(self.path, '1.sgy_first_trace') segy = readSEGY(file) segy[0].stats.sampling_rate = 20 outfile = NamedTemporaryFile().name writeSEGY(segy, outfile) new_segy = readSEGY(outfile) os.remove(outfile) self.assertEqual(new_segy[0].stats.sampling_rate, 20) # The same with the Seismic Unix file. file = os.path.join(self.path, '1.su_first_trace') _su = readSU(file)
def test_writingStarttimeTimestamp0(self): """ If the starttime of the Trace is UTCDateTime(0) it will be interpreted as a missing starttime is not written. Test if this holds True. """ file = os.path.join(self.path, '1.sgy_first_trace') # This file has a set date! with open(file, 'rb') as f: f.seek(3600 + 156, 0) date_time = f.read(10) year, julday, hour, minute, second = unpack('>5h', date_time) self.assertEqual([year == 2005, julday == 353, hour == 15, minute == 7, second == 54], 5 * [True]) # Read and set zero time. segy = readSEGY(file) segy[0].stats.starttime = UTCDateTime(0) with NamedTemporaryFile() as tf: outfile = tf.name writeSEGY(segy, outfile) # Check the new date. with open(outfile, 'rb') as f: f.seek(3600 + 156, 0) date_time = f.read(10) year, julday, hour, minute, second = unpack('>5h', date_time) self.assertEqual([year == 0, julday == 0, hour == 0, minute == 0, second == 0], 5 * [True]) # The same for SU. file = os.path.join(self.path, '1.su_first_trace') # This file has a set date! with open(file, 'rb') as f: f.seek(156, 0) date_time = f.read(10) year, julday, hour, minute, second = unpack('<5h', date_time) self.assertEqual([year == 2005, julday == 353, hour == 15, minute == 7, second == 54], 5 * [True]) # Read and set zero time. su = readSU(file) su[0].stats.starttime = UTCDateTime(0) with NamedTemporaryFile() as tf: outfile = tf.name writeSU(su, outfile) # Check the new date. with open(outfile, 'rb') as f: f.seek(156, 0) date_time = f.read(10) year, julday, hour, minute, second = unpack('<5h', date_time) self.assertEqual([year == 0, julday == 0, hour == 0, minute == 0, second == 0], 5 * [True])
def test_settingDataEncodingWorks(self): """ Test whether or not the enforcing the data encoding works. """ # File ld0042_file_00018.sgy_first_trace uses IBM floating point # representation. file = os.path.join(self.path, 'ld0042_file_00018.sgy_first_trace') st = readSEGY(file) # First test if it even works. with NamedTemporaryFile() as tf: out_file = tf.name writeSEGY(st, out_file) with open(out_file, 'rb') as f: data1 = f.read() # Write again and enforce encoding one which should yield the same # result. writeSEGY(st, out_file, data_encoding=1) with open(out_file, 'rb') as f: data2 = f.read() self.assertTrue(data1 == data2) # Writing IEEE floats which should not require any dtype changes. writeSEGY(st, out_file, data_encoding=5) with open(out_file, 'rb') as f: data3 = f.read() self.assertFalse(data1 == data3)
def test_settingDataEncodingWorks(self): """ Test whether or not the enforcing the data encoding works. """ # File ld0042_file_00018.sgy_first_trace uses IBM floating point # representation. file = os.path.join(self.path, 'ld0042_file_00018.sgy_first_trace') st = readSEGY(file) # First test if it even works. out_file = NamedTemporaryFile().name writeSEGY(st, out_file) with open(out_file, 'rb') as f: data1 = f.read() os.remove(out_file) # Write again and enforce encoding one which should yield the same # result. writeSEGY(st, out_file, data_encoding=1) with open(out_file, 'rb') as f: data2 = f.read() os.remove(out_file) self.assertTrue(data1 == data2) # Writing IEEE floats which should not require any dtype changes. writeSEGY(st, out_file, data_encoding=5) with open(out_file, 'rb') as f: data3 = f.read() os.remove(out_file) self.assertFalse(data1 == data3)
def test_writingModifiedDate(self): """ Tests if the date in Trace.stats.starttime is correctly written in SU and SEGY files. """ # Define new date! new_date = UTCDateTime(2010, 7, 7, 2, 2, 2) with NamedTemporaryFile() as tf: outfile = tf.name # Test for SEGY. file = os.path.join(self.path, 'example.y_first_trace') segy = readSEGY(file) segy[0].stats.starttime = new_date writeSEGY(segy, outfile) segy_new = readSEGY(outfile) self.assertEqual(new_date, segy_new[0].stats.starttime) # Test for SU. file = os.path.join(self.path, '1.su_first_trace') su = readSU(file) su[0].stats.starttime = new_date writeSU(su, outfile) su_new = readSU(outfile) self.assertEqual(new_date, su_new[0].stats.starttime)
def test_enforcingTextualHeaderEncodingWhileWriting(self): """ Tests whether or not the enforcing of the endianness while writing works. """ # File ld0042_file_00018.sgy_first_trace has an EBCDIC encoding. file = os.path.join(self.path, 'ld0042_file_00018.sgy_first_trace') st1 = readSEGY(file) # Save the header to compare it later on. with open(file, 'rb') as f: header = f.read(3200) # First write should remain EBCDIC. with NamedTemporaryFile() as tf: out_file = tf.name writeSEGY(st1, out_file) st2 = readSEGY(out_file) # Compare header. with open(out_file, 'rb') as f: new_header = f.read(3200) self.assertTrue(header == new_header) self.assertEqual(st2.stats.textual_file_header_encoding, 'EBCDIC') # Do once again to enforce EBCDIC. writeSEGY(st1, out_file, textual_header_encoding='EBCDIC') st3 = readSEGY(out_file) # Compare header. with open(out_file, 'rb') as f: new_header = f.read(3200) self.assertTrue(header == new_header) os.remove(out_file) self.assertEqual(st3.stats.textual_file_header_encoding, 'EBCDIC') # Enforce ASCII writeSEGY(st1, out_file, textual_header_encoding='ASCII') st4 = readSEGY(out_file) # Compare header. Should not be equal this time. with open(out_file, 'rb') as f: new_header = f.read(3200) self.assertFalse(header == new_header) os.remove(out_file) self.assertEqual(st4.stats.textual_file_header_encoding, 'ASCII')
def test_enforcingEndiannessWhileWriting(self): """ Tests whether or not the enforcing of the endianness while writing works. """ # File ld0042_file_00018.sgy_first_trace is in big endian. file = os.path.join(self.path, 'ld0042_file_00018.sgy_first_trace') st1 = readSEGY(file) # First write should be big endian. with NamedTemporaryFile() as tf: out_file = tf.name writeSEGY(st1, out_file) st2 = readSEGY(out_file) self.assertEqual(st2.stats.endian, '>') # Do once again to enforce big endian. writeSEGY(st1, out_file, byteorder='>') st3 = readSEGY(out_file) self.assertEqual(st3.stats.endian, '>') # Enforce little endian. writeSEGY(st1, out_file, byteorder='<') st4 = readSEGY(out_file) self.assertEqual(st4.stats.endian, '<')