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Transfer of seismic data to and from SEG Y files

Project description

Segpy is open source software created by Sixty North and licensed under the GNU Affero General Public License.

Alternative commercial license terms are available from Sixty North AS if you wish to redistribute Segpy as part of a proprietary closed source product or deliver software software-as-a-service (SaaS) using Segpy as part of a proprietary closed source service.


Build status: Documentation Status


The segpy package is available on the Python Package Index (PyPI):

The package supports Python 3 only. To install:

$ pip install segpy

What is Segpy?

The SEG-Y file format is one of several standards developed by the Society of Exploration Geophysicists for storing geophysical seismic data. It is an open standard, and is controlled by the SEG Technical Standards Committee, a non-profit organization.

This project aims to implement an open SEG-Y module in Python 3 for transporting seismic data between SEG-Y files and Python data structures in pure Python.

Basic Usage

Here’s a short example which converts non-standard little-endian SEG-Y to standard big-endian SEG-Y:

from segpy.reader import create_reader
from segpy.writer import write_segy

with open('seismic_little.sgy', 'rb') as segy_in_file:
    # The seg_y_dataset is a lazy-reader, so keep the file open throughout.
    seg_y_dataset = create_reader(segy_in_file, endian='<')  # Non-standard Rev 1 little-endian
    # Write the seg_y_dataset out to another file, in big-endian format
    with open('seismic_big.sgy', 'wb') as segy_out_file:
        write_segy(segy_out_file, seg_y_dataset, endian='>')  #  Standard Rev 1 big-endian

The create_reader() function creates Dataset which lazily fetches traces from the file, which is why the file must stay open for read for the duration of use of this dataset. We override the default endian paramers, to specify that the SEG-Y file we’re reading is in non-standard little-endian byte order. On the last line of the example we write the Dataset out to a different file, this time with standard compliant big-endian byte order. Note that the input file must remain open as the write_segy() will only request one trace at a time from the input dataset. This means overal memory usage is very low, and the program can handle arbitrarily large SEG-Y files.


The easiest way to contribute is to use Segpy submit reports for defects or any other issues you come across. Please see CONTRIBUTING.rst for more details.


Segpy was created by – and to meet the needs of – Sixty North. If you require additional features, improved performance, portability to earlier versions of Python, or specific defects fixed (such defects are marked ‘unfunded’ in the GitHub issue tracker) Sixty North’s experienced Segpy maintainers may be available to perform funded development work. Enquire with Sixty North at

Segpy Versions

Segpy 2.0 is a complete re-imagining of a SEG-Y reader in Python 3 and represents a complete break from any and all older versions of Segpy. No attempt has been made to maintain API compatibility with earlier versions of Segpy and no code is shared across versions. Although earlier versions of Segpy were open source, they were never ‘released’ as such. Earlier versions of Segpy are deprecated and completely unsupported.



$ pip install -e .[dev] $ bumpversion minor $ python sdist bdist_wheel $ twine upload –config-file <path>/sixty-north.pypirc dist/* $ git push origin

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