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All fields of the new trace-header definition.

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Robert Smallshire
2015-04-26 23:04:20 +01:00
parent 5cfc1805e9
commit 7da4f755da
1 changed files with 382 additions and 0 deletions
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segpy/trace_header.py
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@@ -171,6 +171,388 @@ class TraceHeaderFormat(metaclass=FormatMeta):
"Group static correction in milliseconds. The time_scalar applies to this value."
)
total_static = field(
Int16, offset=103, default=0, documentation=
"Total static applied in milliseconds. (Zero if no static has been applied). "
"The time_scalar applies to this value."
)
lag_time_a = field(
Int16, offset=105, default=0, documentation=
"Lag time A. Time in milliseconds between end of 240-byte trace identification header and time break. "
"The value is positive if time break occurs after the end of header; negative if time break occurs before the "
"end of header. Time break is defined as the initiation pulse that may be recorded on an auxiliary trace or as "
"otherwise specified by the recording system. The time_scalar applies to this value."
)
lag_time_b = field(
Int16, offset=107, default=0, documentation=
"Lag Time B. Time in milliseconds between time break and the initiation time of the energy source. May be "
"positive or negative. The time_scalar applies to this value."
)
delay_recording_time = field(
Int16, offset=109, default=0, documentation=
"Delay recording time — Time in milliseconds between initiation time of energy source and the time when "
"recording of data samples begins. In SEG Y rev 0 this entry was intended for deep-water work if data "
"recording does not start at zero time. The entry can be negative to accommodate negative start times (i.e. "
"data recorded before time zero, presumably as a result of static application to the data trace). If a "
"non-zero value (negative or positive) is recorded in this entry, a comment to that effect should appear in "
"the Textual File Header. The time_scalar applies to this value."
)
mute_start_time = field(
Int16, offset=111, default=0, documentation=
"Mute time — Start time in milliseconds. The time_scalar applies to this value."
)
mute_end_time = field(
Int16, offset=113, default=0, documentation=
"Mute time — End time in milliseconds. The time_scalar applies to this value."
)
num_samples = field(
Int16, offset=115, default=0, documentation=
"Number of samples in this trace. Highly recommended for all types of data."
)
sample_interval = field(
Int16, offset=117, default=0, documentation=
"Sample interval in microseconds (μs) for this trace. The number of bytes in a trace record must be consistent "
"with the number of samples written in the trace header. This is important for all recording media; but it is "
"particularly crucial for the correct processing of SEG Y data in disk files (see Appendix C). "
"If the fixed length trace flag in bytes 3503-3504 of the Binary File Header is set, the sample interval and " #TODO: field names instead of byte offsets
"number of samples in every trace in the SEG Y file must be the same as the values recorded in the Binary File "
"Header. If the fixed length trace flag is not set, the sample interval and number of samples may vary from "
"trace to trace. Highly recommended for all types of data."
)
gain_type_of_field_instruments = field(
Int16, offset=119, default=0, documentation=
"Gain type of field instruments. 1 = fixed, 2 = binary, 3 = floating point, 4 ... N = optional use."
)
instrument_gain_constant = field(
Int16, offset=121, default=0, documentation=
"Instrument gain constant (dB)."
)
instrument_initial_gain = field(
Int16, offset=123, default=0, documentation=
"Instrument early or initial gain (dB)."
)
correlated = field(
Int16, offset=125, default=1, documentation=
"Correlated: 1 = no, 2 = yes."
)
sweep_frequency_at_start = field(
Int16, offset=127, default=0, documentation=
"Sweep frequency at start (Hz)."
)
sweep_frequency_at_end = field(
Int16, offset=129, default=0, documentation=
"Sweep frequency at end (Hz)."
)
sweep_length = field(
Int16, offset=131, default=0, documentation=
"Sweep length in milliseconds."
)
sweep_type = field(
Int16, offset=133, default=0, documentation=
"Sweep type: 1 = linear, 2 = parabolic, 3 = exponential 4 = other."
)
sweep_trace_taper_length_at_start = field(
Int16, offset=135, default=0, documentation=
"Sweep trace taper length at start in milliseconds."
)
sweep_trace_taper_length_at_end = field(
Int16, offset=137, default=0, documentation=
"Sweep trace taper length at end in milliseconds."
)
taper_type = field(
Int16, offset=139, default=0, documentation=
"Taper type: 1 = linear, 2 = cos2, 3 = other"
)
alias_filter_frequency = field(
Int16, offset=141, default=0, documentation=
"Alias filter frequency (Hz), if used."
)
alias_filter_slope = field(
Int16, offset=143, default=0, documentation=
"Alias filter slope (dB/octave)."
)
notch_filter_frequency = field(
Int16, offset=145, default=0, documentation=
"Notch filter frequency (Hz), if used."
)
notch_filter_slope = field(
Int16, offset=147, default=0, documentation=
"Notch filter slope (dB/octave)."
)
low_cut_frequency = field(
Int16, offset=149, default=0, documentation=
"Low-cut frequency (Hz), if used."
)
high_cut_frequency = field(
Int16, offset=151, default=0, documentation=
"High-cut frequency (Hz), if used."
)
low_cut_slope = field(
Int16, offset=153, default=0, documentation=
"Low-cut slope (dB/octave)."
)
high_cut_slope = field(
Int16, offset=155, default=0, documentation=
"High-cut slope (dB/octave)."
)
year_recorded = field(
Int16, offset=155, default=0, documentation=
"Year data recorded. The 1975 standard is unclear as to whether this should be recorded as a 2-digit or a "
"4-digit year and both have been used. For SEG Y revisions beyond rev 0, the year should be recorded as the "
"complete 4-digit Gregorian calendar year (i.e. the year 2001 should be recorded as 2001 in base 10 "
"(7D1 in base16))."
)
day_of_year = field(
Int16, offset=159, default=0, documentation=
"Day of year. (Julian day for GMT and UTC time basis)."
)
hour_of_day = field(
Int16, offset=161, default=0, documentation=
"Hour of day. (24 hour clock)."
)
minute_of_hour = field(
Int16, offset=163, default=0, documentation=
"Minute of hour."
)
second_of_minute = field(
Int16, offset=165, default=0, documentation=
"Second of minute."
)
time_basis_code = field(
Int16, offset=167, default=0, documentation=
"Time basis code. 1 = Local, 2 = GMT (Greenwich Mean Time), 3 = Other, should be explained in a user defined "
"stanza in the Extended Textual File Header, 4 = UTC (Coordinated Universal Time)."
)
trace_weighting_factor = field(
Int16, offset=169, default=0, documentation=
"Trace weighting factor. Defined as 2**-N volts for the least significant bit. (N = 0, 1, ..., 32767)."
)
geophone_group_num_roll_switch_position_one = field(
Int16, offset=171, default=0, documentation=
"Geophone group number of roll switch position one."
)
geophone_group_num_first_trace_original_field = field(
Int16, offset=173, default=0, documentation=
"Geophone group number of trace number one within original field record."
)
geophone_group_num_last_trace_original_field = field(
Int16, offset=175, default=0, documentation=
"Geophone group number of last trace within original field record."
)
gap_size = field(
Int16, offset=177, default=0, documentation=
"Gap size. (Total number of groups dropped)."
)
over_travel = field(
Int16, offset=179, default=0, documentation=
"Over travel associated with taper at beginning or end of line. 1 = down (or behind) 2 = up (or ahead)"
)
cdp_x = field(
Int32, offset=181, default=0, documentation=
"X coordinate of ensemble (CDP) position of this trace. "
"The coordinate reference system should be identified through an extended header Location Data stanza. "
"The xy_scalar field applies to this value."
)
cdp_y = field(
Int32, offset=185, default=0, documentation=
"Y coordinate of ensemble (CDP) position of this trace. "
"The coordinate reference system should be identified through an extended header Location Data stanza. "
"The xy_scalar field applies to this value."
)
inline_number = field(
Int32, offset=189, default=0, documentation=
"In-line number for 3-D poststack data. If one in-line per SEG Y file is "
"being recorded, this value should be the same for all traces in the file and the same value will be recorded "
"in bytes 3205-3208 of the Binary File Header." # TODO: replace bytes with field name
)
crossline_number = field(
Int32, offset=193, default=0, documentation=
"Cross-line number for 3-D poststack data. This will typically be the same "
"value as the ensemble (CDP) number in Trace Header ensemble_num field, but this does not have to be the case."
)
shotpoint_number = field(
Int32, offset=197, default=0, documentation=
"Shotpoint number. This is probably only applicable to 2-D poststack data. Note that it is assumed that the "
"shotpoint number refers to the source location nearest to the ensemble (CDP) location for a particular trace. "
"If this is not the case, there should be a comment in the Textual File Header explaining what the shotpoint "
"number actually refers to."
)
shotpoint_scalar = field(
Int16, offset=201, default=0, documentation=
"Scalar to be applied to the shotpoint number in trace header field shotpoint_number to give the real value. "
"If positive, scalar is used as a multiplier; if negative as a divisor; if zero the shotpoint number is not "
"scaled (i.e. it is an integer. A typical value will be -10, allowing shotpoint numbers with one decimal digit "
"to the right of the decimal point)."
)
trace_unit = field(
Int16, offset=203, default=0, documentation=
"Trace value measurement unit: "
"-1 = Other (should be described in Data Sample Measurement Units Stanza)"
"0 = Unknown, "
"1 = Pascal (Pa), "
"2 = Volts (v), "
"3 = Millivolts (mV), "
"4 = Amperes (A), "
"5 = Meters (m), "
"6 = Meters per second (m/s), "
"7 = Meters per second squared (m/s^2), "
"8 = Newton (N), "
"9 = Watt (W)"
)
transduction_constant_mantissa = field(
Int32, offset=205, default=0, documentation=
"Transduction Constant mantissa. The mantissa of the multiplicative constant used to convert the Data Trace "
"samples to the Transduction Units (specified in Trace Header transduction_units field)."
"The mantissa of the constant is encoded as a four-byte, two's complement integer. The constant value is given"
"by transduction_constant_mantissa * 10**transduction_constant_exponent."
)
transduction_constant_exponent = field(
Int16, offset=209, default=0, documentation=
"Transduction Constant exponent. The base 10 exponent of the multiplicative constant used to convert the Data "
"Trace samples to the Transduction Units (specified in Trace Header transduction_units field). The constant "
"value is given by transduction_constant_mantissa * 10**transduction_constant_exponent."
)
transduction_units = field(
Int16, offset=211, default=0, documentation=
"Transduction Units. The unit of measurement of the Data Trace samples after they have been multiplied by the "
"Transduction Constant specified in Trace Header fields transduction_constant_mantissa and "
"transduction_constant_exponent. "
"-1 = Other (should be described in Data Sample Measurement Unit stanza), "
"0 = Unknown, "
"1 = Pascal (Pa) ,"
"2 = Volts (v), "
"3 = Millivolts (mV), "
"4 = Amperes (A), "
"5 = Meters (m), "
"6 = Meters per second (m/s), "
"7 = Meters per second squared (m/s2), "
"8 = Newton (N), "
"9 = Watt (W)"
)
device_trace_identifier = field(
Int16, offset=213, default=0, documentation=
"Device/Trace Identifier — The unit number or id number of the device associated with the Data Trace "
"(i.e. 4368 for vibrator serial number 4368 or 20316 for gun 16 on string 3 on vessel 2). This field allows "
"traces to be associated across trace ensembles independently of the trace number (ensemble_trace_num field)."
)
time_scalar = field(
Int16, offset=215, default=0, documentation=
"Scalar to be applied to times specified in Trace Header fields uphole_time_at_source, uphole_time_at_group,"
"source_static_correction, group_static_correction, total_static, lag_time_a, lag_time_b, "
"delay_recording_time, mute_start_time, mute_end_time to give the true time value in milliseconds. "
"Scalar = 1, +10, +100, +1000, or +10,000. If positive, scalar is used as a multiplier; "
"if negative, scalar is used as divisor. A value of zero is assumed to be a scalar value of 1."
)
source_type = field(
Int16, offset=217, default=0, documentation=
"Source Type/Orientation — Defines the type and the orientation of the energy source. The terms vertical, "
"cross-line and in-line refer to the three axes of an orthogonal coordinate system. The absolute azimuthal "
"orientation of the coordinate system axes can be defined in the Bin Grid Definition Stanza."
"-1 to -n = Other (should be described in Source Type/Orientation stanza), "
"0 = Unknown, "
"1 = Vibratory - Vertical orientation, "
"2 = Vibratory - Cross-line orientation, "
"3 = Vibratory - In-line orientation, "
"4 = Impulsive - Vertical orientation, "
"5 = Impulsive - Cross-line orientation, "
"6 = Impulsive - In-line orientation, "
"7 = Distributed Impulsive - Vertical orientation, "
"8 = Distributed Impulsive - Cross-line orientation, "
"9 = Distributed Impulsive - In-line orientation, "
)
source_energy_direction = field(
Int32, offset=219, default=0, documentation= # TODO: This is six bytes. What is the format?
"Source Energy Direction with respect to the source orientation. The positive orientation direction is "
"defined in Bytes 217-218 of the Trace Header. The energy direction is encoded in tenths of degrees "
"(i.e. 347.8° is encoded as 3478)."
)
source_measurement_mantissa = field(
Int32, offset=225, default=0, documentation=
"Source Measurement mantissa. Describes the source effort used to generate the trace. The measurement can be "
"simple, qualitative measurements such as the total weight of explosive used or the peak air gun pressure or "
"the number of vibrators times the sweep duration. Although these simple measurements are acceptable, it is "
"preferable to use true measurement units of energy or work. The constant is encoded as a four-byte, two's "
"complement integer (source_measurement_mantissa) and a two-byte, two's complement integer "
"source_measurement_exponent) which is the power of ten exponent "
"(i.e. source_measurement_mantissa * 10**source_measurement_exponent)."
)
source_measurement_exponent = field(
Int16, offset=229, default=0, documentation=
"Source Measurement exponent. Describes the source effort used to generate the trace. The measurement can be "
"simple, qualitative measurements such as the total weight of explosive used or the peak air gun pressure or "
"the number of vibrators times the sweep duration. Although these simple measurements are acceptable, it is "
"preferable to use true measurement units of energy or work. The constant is encoded as a four-byte, two's "
"complement integer (source_measurement_mantissa) and a two-byte, two's complement integer "
"source_measurement_exponent) which is the power of ten exponent "
"(i.e. source_measurement_mantissa * 10**source_measurement_exponent)."
)
source_measurement_unit = field(
Int16, offset=231, default=0, documentation=
"Source Measurement Unit. The unit used for the source measurement."
"-1 = Other (should be described in Source Measurement Unit stanza), "
"0 = Unknown, "
"1 = Joule (J), "
"2 = Kilowatt (kW), "
"3 = Pascal (Pa), "
"4 = Bar (Bar), "
"4 = Bar-meter (Bar-m), "
"5 = Newton (N), "
"6 = Kilograms (kg)"
)
class TraceHeader(metaclass=BuildFromFormat, format_class=TraceHeaderFormat):
pass