Command-Line Usage¶

Introduction¶

segy comes with a useful CLI tool to interrogate SEG-Y files either on disk or any remote store.

Command Line Usage¶

SEG-Y provides a convenient command-line-interface (CLI) to do various tasks.

For each command / subcommand you can provide --help argument to get information about usage.

At the highest level, the segy command line offers various options to choose from. Below you can see the usage for the main entry point.

Dumping Data¶

When we use segy dump subcommand, we have some options to choose from. As usual, the uri (local or remote paths) will allow us to use the same toolkit for local and cloud / web files.

For the CLI demos, we will use a public SEG-Y file located in Amazon Web Services’ (AWS) Simple Storage Service (S3), also known as a cloud object store.

This dataset, the Stratton 3D is made available for worldwide education and training by the Bureau of Economic Geology at the University of Texas at Austin. Available information and data acquisition details are accessible via the SEG Wiki.

We will take a look at the 3D unprocessed shot gathers (swath 1).

Note

To run the below examples, set your S3 configuration. More details in Configuration Options.

export SEGY_STORAGE_OPTIONS='{"anon": true}'

Basic Info¶

Now that we can access public S3 buckets anonymously, we can output a basic summary of the file using the info command.

$ segy dump info \
    s3://open.source.geoscience/open_data/stratton/segy/navmerged/swath_1_geometry.sgy
{
  "uri": "s3://open.source.geoscience/open_data/stratton/segy/navmerged/swath_1_geometry.sgy",
  "segyStandard": 0.0,
  "numTraces": 136530,
  "samplesPerTrace": 3000,
  "sampleInterval": 2000,
  "fileSize": 1671130800
}

File Text Header¶

Let’s take a look at the text header.

$ segy dump text-header \
    s3://open.source.geoscience/open_data/stratton/segy/navmerged/swath_1_geometry.sgy
C 1 CLIENT: BUREAU OF ECONOMIC GEOLOGY  COMPANY: HALLIBURTON GS CREW: #1768
C 2 SURVEY: WARDNER LEASE 3-D (STRATTON FIELD)       AREA: NUECES CO, TEXAS
C 3 RECORDING DATE: 1992
C 4 2MS SAMPLE INTERVAL   3000 SAMPLES/TRACE   4 BYTES/SAMPLE
C 5
C 6 DATA STORED AS SEG-Y FORMAT #1 (IBM FLOATING POINT)
C 7 KEY STANDARD TRACE HEADERS USED:
C 8 FFID =  9-12
C 9 SOURCE X = 73-76  SOURCE Y = 77-80 SOURCE Z = 45-48
C10    REC X = 81-84     REC Y = 85-88    REC Z = 41-44
C11 COORD SCALER = 71-72   ELEV. SCALER = 69-70
C12
C13 NOTE: X = NORTHING, Y = EASTING (RIGHT-HAND Z-DOWN COORDINATES)
C14
C15 NON-STANDARD TRACE HEADERS:
C16 CHANNEL  = 25-28
C17    CHANNELS 1-720 ARE LIVE DATA, 996-999 ARE AUXILIARY TRACES
C18 RECEIVER LINE = 181-184  RECEIVER NUMBER = 185-188
C19 SOURCE LINE = 189-192  SOURCE NUMBER = 193-196
C20
C21 PROCESSED BY EGL: EXPLORATION GEOPHYSICS LABORATORY (PAUL E MURRAY)
C22 BUREAU OF ECONOMIC GEOLOGY, JACKSON SCHOOL OF GEOSCIENCES, UT - AUSTIN
C23 **********PROCESSING**********
C24 1) FIELD SEG-Y FILES REFORMAT TO EGLTOOLS SDF FORMAT
C25 2) CHANNEL RENUMBERING AND GEOMETRY LOADED TO HEADERS
C26 3) PADDED TRACES, BAD AND TEST RECORDS REMOVED
C27 4) REFORMAT TO SEG-Y
C28
C29
C30 SWATH 1 OF 4 CONTAINS FFIDS 1-262
C31
C32 COORDINATES ARE IN FEET
C33 ELLIPSOID: CLARKE 1866
C34 DATUM = NAD27
C35 TEXAS STATE PLANE SOUTH ZONE, LAMBERT PROJECTION
C36 FALSE NORTHING =  485012.85
C37 FALSE EASTING =  2000000.00
C38
C39 written from EGLTools for Matlab on 14-Dec-2009
C40 END EBCDIC

File Binary Header¶

$ segy dump binary-header \
    s3://open.source.geoscience/open_data/stratton/segy/navmerged/swath_1_geometry.sgy
{
  "job_id": 0,
  "line_no": 0,
  "reel_no": 1,
  "data_traces_ensemble": 724,
  "aux_traces_ensemble": 0,
  "sample_interval": 2000,
  "sample_interval_orig": 2000,
  "samples_per_trace": 3000,
  "samples_per_trace_orig": 3000,
  "data_sample_format": 1,
  "ensemble_fold": 724,
  "trace_sorting": 1,
  "vertical_sum": 0,
  "sweep_freq_start": -30480,
  "sweep_freq_end": -2692,
  "sweep_length": 0,
  "sweep_type": 0,
  "sweep_trace_no": 0,
  "sweep_taper_start": 0,
  "sweep_taper_end": 0,
  "taper_type": 0,
  "correlated_traces": 0,
  "binary_gain": 0,
  "amp_recovery_method": 0,
  "measurement_system": 0,
  "impulse_signal_polarity": 0,
  "vibratory_polarity": 0
}

Trace Header¶

This is how we can get three header fields for a few traces.

$ segy dump trace-header s3://open.source.geoscience/open_data/stratton/segy/navmerged/swath_1_geometry.sgy \
    --index 100 --index 101 --index 500 --index 501 \
    --field source_coord_x --field source_coord_y \
    --field group_coord_x --field group_coord_y \
    --field coordinate_scalar
             source_coord_x  source_coord_y  group_coord_x  group_coord_y  coordinate_scalar
trace_index
100                70628086       219412572       70616707      218875760               -100
101                70628086       219412572       70616695      218864765               -100
500                70650057       219412488       70880968      219271571               -100
501                70650057       219412488       70880940      219260587               -100

Configuration Options¶

When accessing public datasets from S3, we need to set SegySettings().storage_options = {"anon": True} for anonymous access. SegySettings exposes all configuration options as environment variables. We just need to set storage_options with the JSON string {"anon": true}. On Linux you can do this by the command below. Environment variables can be configured in many ways, please refer to the options for your specific Operating System (OS).

export SEGY_STORAGE_OPTIONS='{"anon": true}'