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Some progress towards complete support for writing SEG Y
This commit is contained in:
Robert Smallshire
@@ -0,0 +1,147 @@
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from revisions import SEGY_REVISION_0, SEGY_REVISION_1
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TEMPLATE = """
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C 1 CLIENT { client } COMPANY { company } CREW NO {crew }
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C 2 LINE { line } AREA { area } MAP ID { map_id }
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C 3 REEL NO {reelnum} DAY-START OF REEL {d} YEAR {yr} OBSERVER {observer }
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C 4 INSTRUMENT: MFG { mfg } MODEL { model } SERIAL NO { serial }
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C 5 DATA TRACES/RECORD {dtpr} AUXILIARY TRACES/RECORD {atpr } CDP FOLD {cdpfold}
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C 6 SAMPLE INTERVAL {intvl} SAMPLES/TRACE {spt} BITS/IN {bi} BYTES/SAMPLE {bps }
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C 7 RECORDING FORMAT {rfmt} FORMAT THIS REEL {ftr } MEASUREMENT SYSTEM {measmnt}
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C 8 SAMPLE CODE: FLOATING PT {f} FIXED PT {x} FIXED PT-GAIN {g} CORRELATED {cor}
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C 9 GAIN TYPE: FIXED {i} BINARY {b} FLOATING POINT {c} OTHER {other }
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C10 FILTERS: ALIAS {a }HZ NOTCH {n }HZ BAND {b1}-{b2 }HZ SLOPE {s}-{s2}DB/OCT
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C11 SOURCE: TYPE {type } NUMBER/POINT {npt } POINT INTERVAL {point_interval }
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C12 PATTERN: {source_pattern } LENGTH {lent} WIDTH {width }
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C13 SWEEP: START {ss}HZ END {se}HZ LENGTH {lms}MS CHANNEL NO {q} TYPE {cd }
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C14 TAPER: START LENGTH {tsl }MS END LENGTH {tel }MS TYPE {taper_type }
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C15 SPREAD: OFFSET {off } MAX DISTANCE {md } GROUP INTERVAL {group_interval }
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C16 GEOPHONES: PER GROUP {p} SPACING {y} FREQUENCY {r} MFG {gmfg } MODEL {gmod}
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C17 PATTERN: {geophone_pattern } LENGTH {glen} WIDTH {geophone_width }
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C18 TRACES SORTED BY: RECORD {u} CDP {v} OTHER { sort_other }
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C19 AMPLITUDE RECOVERY: NONE {ar} SPHERICAL DIV {sd } AGC {} OTHER {ar_other }
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C20 MAP PROJECTION {map_projection } ZONE ID {zid} COORDINATE UNITS {co_units }
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C21 PROCESSING: { processing1 }
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C22 PROCESSING: { processing2 }
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C23 { unassigned1 }
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C24 { unassigned2 }
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C25 { unassigned3 }
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C26 { unassigned4 }
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C27 { unassigned5 }
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C28 { unassigned6 }
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C29 { unassigned7 }
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C30 { unassigned8 }
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C31 { unassigned9 }
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C32 { unassigned10 }
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C33 { unassigned11 }
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C34 { unassigned12 }
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C35 { unassigned13 }
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C36 { unassigned14 }
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C37 { unassigned15 }
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C38 { unassigned16 }
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C39 { unassigned17 }
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C40 { end_marker }
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"""
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END_TEXTUAL_HEADER = 'END TEXTUAL HEADER'
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END_EBCDIC = 'END EBCDIC'
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END_MARKERS = {SEGY_REVISION_0: END_EBCDIC,
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SEGY_REVISION_1: END_TEXTUAL_HEADER}
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TEMPLATE_FIELD_NAMES = {'client': 'client',
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'company': 'company',
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'crew': 'crew_number',
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'line': 'line',
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'area': 'area',
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'map_id': 'map_id',
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'reelnum': 'reel_number',
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'd': 'day_start_of_reel',
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'yr': 'year',
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'observer': 'observer',
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'mfg': 'instrument_manufacturer',
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'model': 'instrument_model',
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'serial': 'instrument_serial',
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'dtpr': 'data_traces_per_record',
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'atpr': 'auxiliary_traces_per_record',
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'cdpfold': 'cdp_fold',
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'intvl': 'sample_interval',
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'spt': 'samples_per_trace',
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'bi': 'bits_per_inch',
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'bps': 'bytes_per_sample',
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'rfmt': 'recording_format',
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'ftr': 'format_this_reel',
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'measmnt': 'measurement_system',
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'f': 'sample_code_floating_point',
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'x': 'sample_code_fixed_point',
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'g': 'sample_code_fixed_point_gain',
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'cor': 'sample_code_correlated',
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'i': 'gain_type_fixed',
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'b': 'gain_type_binary',
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'c': 'gain_type_fixed_point_gain',
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'other': 'gain_type_other',
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'a': 'filters_alias_hz',
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'n': 'filters_notch_hz',
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'b1': 'filters_band_lower_hz',
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'b2': 'filters_band_upper_hz',
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's': 'filters_slope_lower_db_per_oct',
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's2': 'filters_slope_upper_db_per_oct',
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'type': 'source_type',
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'npt': 'source_number_per_point',
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'point_interval': 'source_point_interval',
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'source_pattern': 'source_pattern',
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'lent': 'source_length',
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'width': 'source_width',
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'ss': 'sweep_start_hz',
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'se': 'sweep_end_hz',
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'lms': 'sweep_length_ms',
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'q': 'sweep_channel_number',
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'cd': 'sweep_type',
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'tsl': 'taper_start_length_ms',
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'tel': 'taper_end_length_ms',
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'taper_type': 'taper_type',
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'off': 'spread_offset',
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'md': 'spread_max_distance',
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'group_interval': 'spread_group_interval',
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'p': 'geophones_per_group',
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'y': 'geophone_spacing',
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'r': 'geophone_frequency',
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'gmfg': 'geophone_manufacturer',
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'gmod': 'geophone_model',
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'geophone_pattern': 'geophone_pattern',
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'glen': 'geophone_length',
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'geophone_width': 'geophone_width',
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'u': 'traces_sorted_by_record',
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'v': 'traces_sorted_by_cdp',
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'sort_other': 'traces_sorted_by_other',
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'ar': 'amplitude_recovery_none',
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'sd': 'amplitude_recovery_spherical_div',
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'': 'amplitude_recovery_agc',
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'ar_other': 'amplitude_recovery_other',
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'map_projection': 'map_projection',
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'zid': 'zone_id',
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'co_units': 'coordinate_units',
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'processing1': 'processing1',
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'processing2': 'processing2',
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'unassigned1': 'unassigned1',
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'unassigned2': 'unassigned2',
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'unassigned3': 'unassigned3',
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'unassigned4': 'unassigned4',
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'unassigned5': 'unassigned5',
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'unassigned6': 'unassigned6',
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'unassigned7': 'unassigned7',
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'unassigned8': 'unassigned8',
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'unassigned9': 'unassigned9',
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'unassigned10': 'unassigned10',
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'unassigned11': 'unassigned11',
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'unassigned12': 'unassigned12',
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'unassigned13': 'unassigned13',
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'unassigned14': 'unassigned14',
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'unassigned15': 'unassigned15',
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'unassigned16': 'unassigned16',
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'unassigned17': 'unassigned17',
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'end_marker': 'end_marker'
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}
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INV_TEMPLATE_FIELD_NAMES = dict((v, k) for k, v in TEMPLATE_FIELD_NAMES.items())
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+109
-2
@@ -1,8 +1,10 @@
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from array import array
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from collections import namedtuple
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from collections import namedtuple, OrderedDict
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import itertools
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from itertools import zip_longest
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import os
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import struct
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import re
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from catalog import CatalogBuilder
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from datatypes import CTYPES, size_in_bytes
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@@ -10,10 +12,13 @@ from encoding import guess_encoding
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from binary_reel_header_definition import HEADER_DEF
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from ibm_float import ibm2ieee, ieee2ibm
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from revisions import canonicalize_revision
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import textual_reel_header_definition
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from trace_header_definition import TRACE_HEADER_DEF
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from util import file_length, batched, pad, round_up
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from util import file_length, batched, pad, round_up, complementary_slices
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from portability import EMPTY_BYTE_STRING
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CARD_LENGTH = 80
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CARDS_PER_HEADER = 40
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@@ -476,6 +481,95 @@ def unpack_values(buf, count, item_size, fmt, endian='>'):
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# swapping ourselves.
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def format_standard_textual_header(revision, **kwargs):
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"""Produce a standard SEG Y textual header.
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Args:
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revision: The SEG Y revision.
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**kwargs: Named arguments corresponding to the values in the
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textual_reel_header_definition.TEMPLATE_FIELD_NAMES dictionary,
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which in turn correspond to the placeholders in the
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textual_reel_header_definition.TEMPLATE string. Any omitted
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arguments will result in placeholders being replaced by spaces.
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If the end_marker argument is not supplied, an appropriate end
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marker will be selected based on the SEG Y revision. For standard
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end markers consider using textual_reel_header_definition.END_TEXTUAL_HEADER
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or textual_reel_header_definition.END_EBCDIC.
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Returns:
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A list of forty Unicode strings.
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Usage:
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header = format_standard_textual_header(1,
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client="Lundin",
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company="Western Geco",
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crew_number=123,
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processing1="Sixty North AS",
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sweep_start_hz=10,
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sweep_end_hz=1000,
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sweep_length_ms=10000,
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sweep_channel_number=3,
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sweep_type='spread')
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"""
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kwargs.setdefault('end_marker', textual_reel_header_definition.END_MARKERS[revision])
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template = textual_reel_header_definition.TEMPLATE
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placeholder_slices = parse_template(template)
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background_slices = complementary_slices(placeholder_slices.values(), 0, len(template))
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chunks = []
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for bg_slice, placeholder in zip_longest(background_slices, placeholder_slices.items()):
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if bg_slice is not None:
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chunks.append(template[bg_slice])
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if placeholder is not None:
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ph_name, ph_slice = placeholder
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ph_arg_name = textual_reel_header_definition.TEMPLATE_FIELD_NAMES[ph_name]
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ph_value = kwargs.pop(ph_arg_name, '')
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ph_len = ph_slice.stop - ph_slice.start
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substitute = str(ph_value)[:ph_len].ljust(ph_len, ' ')
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chunks.append(substitute)
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if len(kwargs) > 0:
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raise TypeError("The following keyword arguments did not correspond to template placeholders: {!r}"
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.format(list(kwargs.keys())))
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concatenation = ''.join(chunks)
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lines = concatenation.splitlines(keepends=False)
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return lines[1:] # Omit the first and last lines, which are artifacts of the multiline string template
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def parse_template(template):
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"""Parse a template to produce a dictionary of placeholders.
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Args:
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template: The template string containing { field-name } style fixed-width fields.
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Returns:
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A OrderedDict mapping field names to slices objects which can be used to index
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into the template string. The order of the entries is the same as the order within
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which they occur in the template.
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"""
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PATTERN = r'\{\s*(\w*)\s*\}'
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regex = re.compile(PATTERN)
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matches = regex.finditer(template)
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fields = OrderedDict()
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for match in matches:
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name = match.group(1)
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start = match.start()
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end = match.end()
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fields[name] = slice(start, end)
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return fields
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def write_textual_reel_header(fh, lines, encoding):
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"""Write the SEG Y card image header, also known as the textual header
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@@ -721,3 +815,16 @@ def _compile_trace_header_record():
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TraceHeader = _compile_trace_header_record()
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if __name__ == '__main__':
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from pprint import pprint as pp
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header = format_standard_textual_header(1,
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client="Lundin",
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company="Western Geco",
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crew_number=123,
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processing1="Sixty North AS",
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sweep_start_hz=10,
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sweep_end_hz=1000,
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sweep_length_ms=10000,
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sweep_channel_number=3,
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sweep_type='spread')
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pp(header, width=200)
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@@ -42,6 +42,61 @@ def pad(iterable, padding=None, size=None):
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return itertools.islice(pad(iterable, padding), size)
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def complementary_slices(slices, start=None, stop=None):
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"""Compute a complementary set of slices which alternate with given slices to form a contiguous range.
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Given,
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Start Stop
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[-----) [-----) [----)
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produces,
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[--) [----) [-) [---)
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Args:
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slices: An sequence of existing slices
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start: An optional start index, defaults to the start of the first slice.
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stop: An optional one-beyond-the-end index, defaults to the stop attribute of the last slice.
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Yields:
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A complementary series of slices which alternate with the supplied slices. The number of returned
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slices will always be len(slices) + 1 since both leading and trailing slices will always be returned.
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Note the some of the returned slices may be 'empty' (having zero length).
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"""
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if start is None:
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start = slices[0].start
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if stop is None:
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stop = slices[-1].stop
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index = start
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for s in slices:
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yield slice(index, s.start)
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index = s.stop
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yield slice(index, stop)
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def roundrobin(*iterables):
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"""Take items from each iterable in turn until all iterables are exhausted.
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roundrobin('ABC', 'D', 'EF') --> A D E B F C
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"""
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# Recipe credited to George Sakkis
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pending = len(iterables)
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nexts = itertools.cycle(iter(it).__next__ for it in iterables)
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while pending:
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try:
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for n in nexts:
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print
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yield n()
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except StopIteration:
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pending -= 1
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nexts = itertools.cycle(itertools.islice(nexts, pending))
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def contains_duplicates(sorted_iterable):
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"""Determine in an iterable series contains duplicates.
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Reference in New Issue
Block a user