def test_large_sample_rate_interval_raises(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 = _read_segy(file)
segy.stats.textual_file_header = \
_patch_header(segy.stats.textual_file_header)
# Set the largest possible delta value which should just work.
segy[0].stats.delta = 0.065535
_write_segy(segy, outfile)
# Slightly larger should raise.
segy[0].stats.delta = 0.065536
self.assertRaises(SEGYSampleIntervalError, _write_segy, segy,
outfile)
# Same for SU.
file = os.path.join(self.path, '1.su_first_trace')
su = _read_su(file)
# Set the largest possible delta value which should just work.
su[0].stats.delta = 0.065535
_write_su(su, outfile)
# Slightly larger should raise.
su[0].stats.delta = 0.065536
self.assertRaises(SEGYSampleIntervalError, _write_su, su, outfile)
def test_large_sample_rate_interval_raises(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 = _read_segy(file)
segy.stats.textual_file_header = \
_patch_header(segy.stats.textual_file_header)
# Set the largest possible delta value which should just work.
segy[0].stats.delta = 0.065535
_write_segy(segy, outfile)
# Slightly larger should raise.
segy[0].stats.delta = 0.065536
self.assertRaises(SEGYSampleIntervalError, _write_segy, segy,
outfile)
# Same for SU.
file = os.path.join(self.path, '1.su_first_trace')
su = _read_su(file)
# Set the largest possible delta value which should just work.
su[0].stats.delta = 0.065535
_write_su(su, outfile)
# Slightly larger should raise.
su[0].stats.delta = 0.065536
self.assertRaises(SEGYSampleIntervalError, _write_su, su, outfile)
def test_writing_starttime_timestamp_0(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(b'>5h', date_time)
self.assertEqual([
year == 2005, julday == 353, hour == 15, minute == 7, second == 54
], 5 * [True])
# Read and set zero time.
segy = _read_segy(file)
segy.stats.textual_file_header = \
_patch_header(segy.stats.textual_file_header)
segy[0].stats.starttime = UTCDateTime(0)
with NamedTemporaryFile() as tf:
outfile = tf.name
_write_segy(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(b'>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(b'<5h', date_time)
self.assertEqual([
year == 2005, julday == 353, hour == 15, minute == 7, second == 54
], 5 * [True])
# Read and set zero time.
su = _read_su(file)
su[0].stats.starttime = UTCDateTime(0)
with NamedTemporaryFile() as tf:
outfile = tf.name
_write_su(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(b'<5h', date_time)
self.assertEqual(
[year == 0, julday == 0, hour == 0, minute == 0, second == 0],
5 * [True])
def test_issue_377(self):
"""
Tests that _read_segy() and stream.write() should handle negative trace
header values.
"""
filename = os.path.join(self.path, 'one_trace_year_11.sgy')
st = _read_segy(filename)
st[0].stats.segy.trace_header['source_coordinate_x'] = -1
st.stats.textual_file_header = \
_patch_header(st.stats.textual_file_header)
with NamedTemporaryFile() as tf:
outfile = tf.name
st.write(outfile, format='SEGY')
def test_issue_377(self):
"""
Tests that _read_segy() and stream.write() should handle negative trace
header values.
"""
filename = os.path.join(self.path, 'one_trace_year_11.sgy')
st = _read_segy(filename)
st[0].stats.segy.trace_header['source_coordinate_x'] = -1
st.stats.textual_file_header = \
_patch_header(st.stats.textual_file_header)
with NamedTemporaryFile() as tf:
outfile = tf.name
st.write(outfile, format='SEGY')
def test_writing_starttime_timestamp_0(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(b'>5h', date_time)
self.assertEqual([year == 2005, julday == 353, hour == 15, minute == 7,
second == 54], 5 * [True])
# Read and set zero time.
segy = _read_segy(file)
segy.stats.textual_file_header = \
_patch_header(segy.stats.textual_file_header)
segy[0].stats.starttime = UTCDateTime(0)
with NamedTemporaryFile() as tf:
outfile = tf.name
_write_segy(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(b'>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(b'<5h', date_time)
self.assertEqual([year == 2005, julday == 353, hour == 15, minute == 7,
second == 54], 5 * [True])
# Read and set zero time.
su = _read_su(file)
su[0].stats.starttime = UTCDateTime(0)
with NamedTemporaryFile() as tf:
outfile = tf.name
_write_su(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(b'<5h', date_time)
self.assertEqual([year == 0, julday == 0, hour == 0, minute == 0,
second == 0], 5 * [True])
def test_enforcing_textual_header_encoding_while_writing(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 = _read_segy(file)
# Save the header to compare it later on.
with open(file, 'rb') as f:
header = f.read(3200)
# All newly written header will have the file revision number and
# the end header mark set - just also set them in the old header.
header = _patch_header(header, ebcdic=True)
# First write should remain EBCDIC.
with NamedTemporaryFile() as tf:
out_file = tf.name
_write_segy(st1, out_file)
st2 = _read_segy(out_file)
# Compare header.
with open(out_file, 'rb') as f:
new_header = f.read(3200)
# re-encode both to ASCII to easily compare them.
self.assertEqual(
header.decode("EBCDIC-CP-BE").encode("ASCII"),
new_header.decode("EBCDIC-CP-BE").encode("ASCII"))
self.assertEqual(st2.stats.textual_file_header_encoding,
'EBCDIC')
# Do once again to enforce EBCDIC.
_write_segy(st1, out_file, textual_header_encoding='EBCDIC')
st3 = _read_segy(out_file)
# Compare header.
with open(out_file, 'rb') as f:
new_header = f.read(3200)
self.assertEqual(header, new_header)
os.remove(out_file)
self.assertEqual(st3.stats.textual_file_header_encoding,
'EBCDIC')
# Enforce ASCII
_write_segy(st1, out_file, textual_header_encoding='ASCII')
st4 = _read_segy(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_enforcing_textual_header_encoding_while_writing(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 = _read_segy(file)
# Save the header to compare it later on.
with open(file, 'rb') as f:
header = f.read(3200)
# All newly written header will have the file revision number and
# the end header mark set - just also set them in the old header.
header = _patch_header(header, ebcdic=True)
# First write should remain EBCDIC.
with NamedTemporaryFile() as tf:
out_file = tf.name
_write_segy(st1, out_file)
st2 = _read_segy(out_file)
# Compare header.
with open(out_file, 'rb') as f:
new_header = f.read(3200)
# re-encode both to ASCII to easily compare them.
self.assertEqual(
header.decode("EBCDIC-CP-BE").encode("ASCII"),
new_header.decode("EBCDIC-CP-BE").encode("ASCII"))
self.assertEqual(st2.stats.textual_file_header_encoding,
'EBCDIC')
# Do once again to enforce EBCDIC.
_write_segy(st1, out_file, textual_header_encoding='EBCDIC')
st3 = _read_segy(out_file)
# Compare header.
with open(out_file, 'rb') as f:
new_header = f.read(3200)
self.assertEqual(header, new_header)
os.remove(out_file)
self.assertEqual(st3.stats.textual_file_header_encoding,
'EBCDIC')
# Enforce ASCII
_write_segy(st1, out_file, textual_header_encoding='ASCII')
st4 = _read_segy(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_writing_new_sampling_rate(self):
"""
Setting a new sample rate works.
"""
file = os.path.join(self.path, '1.sgy_first_trace')
segy = _read_segy(file)
segy.stats.textual_file_header = \
_patch_header(segy.stats.textual_file_header)
segy[0].stats.sampling_rate = 20
with NamedTemporaryFile() as tf:
outfile = tf.name
_write_segy(segy, outfile)
new_segy = _read_segy(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')
_read_su(file)
def test_writing_new_sampling_rate(self):
"""
Setting a new sample rate works.
"""
file = os.path.join(self.path, '1.sgy_first_trace')
segy = _read_segy(file)
segy.stats.textual_file_header = \
_patch_header(segy.stats.textual_file_header)
segy[0].stats.sampling_rate = 20
with NamedTemporaryFile() as tf:
outfile = tf.name
_write_segy(segy, outfile)
new_segy = _read_segy(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')
_read_su(file)