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https://github.com/wassname/segpy.git
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Robert Smallshire
141 lines
4.6 KiB
Python
141 lines
4.6 KiB
Python
#!/usr/bin/env python3
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"""Extract a timeslice from a 3D seismic volume to a Numpy array.
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This utility assumes the inline and crossline numbers are evenly spaced.
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Each inline of the source data will be represented as a single row, and
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each crossline as a single column in the resulting 2D array.
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Usage: timeslice.py [-h] [--dtype DTYPE] [--null NULL]
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segy-file npy-file slice-index
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Positional arguments:
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segy-file Path to an existing SEG Y file of 3D seismic data
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npy-file Path to the Numpy array file to be created for the timeslice
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slice-index Zero based index of the time slice to be extracted
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Optional arguments:
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-h, --help show this help message and exit
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--dtype DTYPE Numpy data type. If not provided a dtype compatible with the
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SEG Y data will be used.
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--null NULL Sample value to use for missing or short traces.
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Example:
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timeslice.py stack_final_int8.sgy slice_800.npy 800 --null=42.0 --dtype=f
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"""
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import argparse
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import os
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import sys
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import traceback
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import numpy as np
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from segpy.reader import create_reader
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from segpy_numpy.dtypes import make_dtype
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class DimensionalityError(Exception):
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pass
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def extract_timeslice(segy_filename, out_filename, slice_index, dtype=None, null=0):
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"""Extract a timeslice from a 3D SEG Y file to a Numpy NPY file.
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Args:
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segy_filename: Filename of a SEG Y file.
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out_filename: Filename of the NPY file.
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slice_index: The zero-based index (increasing with depth) of the slice to be extracted.
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dtype: Optional Numpy dtype for the result array. If not provided a dtype compatible with
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the SEG Y data will be used.
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null: Optional sample value to use for missing or short traces. Defaults to zero.
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"""
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with open(segy_filename, 'rb') as segy_file:
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segy_reader = create_reader(segy_file)
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if dtype is None:
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dtype = make_dtype(segy_reader.data_sample_format)
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if segy_reader.dimensionality != 3:
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raise DimensionalityError("Cannot slice {n} dimensional seismic.".format(segy_reader.dimensionality))
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i_size = segy_reader.num_inlines()
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x_size = segy_reader.num_xlines()
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t_size = segy_reader.max_num_trace_samples()
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if not (0 <= slice_index < t_size):
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raise ValueError("Time slice index {0} out of range {} to {}".format(slice_index, 0, t_size))
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timeslice = np.full((i_size, x_size), null, dtype)
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for inline_num, xline_num in segy_reader.inline_xline_numbers():
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trace_index = segy_reader.trace_index((inline_num, xline_num))
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trace = segy_reader.trace_samples(trace_index)
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try:
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sample = trace[slice_index]
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except IndexError:
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sample = null
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i_index = segy_reader.inline_numbers().index(inline_num)
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x_index = segy_reader.xline_numbers().index(xline_num)
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timeslice[i_index, x_index] = sample
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np.save(out_filename, timeslice)
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def nullable_dtype(s):
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return None if s == "" else np.dtype(s)
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def main(argv=None):
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parser = argparse.ArgumentParser()
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parser.add_argument("segy_file", metavar="segy-file",
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help="Path to an existing SEG Y file of 3D seismic data")
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parser.add_argument("npy_file", metavar="npy-file",
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help="Path to the Numpy array file to be created for the timeslice")
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parser.add_argument("slice_index", metavar="slice-index", type=int,
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help="Zero based index of the time slice to be extracted", )
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parser.add_argument("--dtype", type=nullable_dtype, default="",
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help="Numpy data type. If not provided a dtype compatible with the SEG Y data will be used.")
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parser.add_argument("--null", type=float, default=0.0,
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help="Sample value to use for missing or short traces.")
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if argv is None:
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argv = sys.argv[1:]
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args = parser.parse_args(argv)
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try:
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extract_timeslice(args.segy_file,
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args.npy_file,
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args.slice_index,
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args.dtype,
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args.null)
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except (FileNotFoundError, IsADirectoryError) as e:
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print(e, file=sys.stderr)
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return os.EX_NOINPUT
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except PermissionError as e:
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print(e, file=sys.stderr)
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return os.EX_NOPERM
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except Exception as e:
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traceback.print_exception(type(e), e, e.__traceback__, file=sys.stderr)
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return os.EX_SOFTWARE
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return os.EX_OK
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if __name__ == '__main__':
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sys.exit(main())
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