segyio, SEGY文件的快速 python 库.zip

# segyio # [](https://travis-ci.org/equinor/segyio) [](https://ci.appveyor.com/project/statoil-travis/segyio) [](https://pyup.io/repos/github/equinor/segyio/) [](https://pyup.io/repos/github/equinor/segyio/) [readthedocs](https://segyio.readthedocs.io/) ## Index ## * [Introduction](#introduction) * [Feature summary](#feature-summary) * [Getting started](#getting-started) * [Quick start](#quick-start) * [Get segyio](#get-segyio) * [Build segyio](#build-segyio) * [Tutorial](#tutorial) * [Basics](#basics) * [Modes](#modes) * [Mode examples](#mode-examples) * [Goals](#project-goals) * [Contributing](#contributing) * [Examples](#examples) * [Common issues](#common-issues) * [History](#history) ## Introduction ## Segyio is a small LGPL licensed C library for easy interaction with SEG-Y and Seismic Unix formatted seismic data, with language bindings for Python and Matlab. Segyio is an attempt to create an easy-to-use, embeddable, community-oriented library for seismic applications. Features are added as they are needed; suggestions and contributions of all kinds are very welcome. To catch up on the latest development and features, see the [changelog](changelog.md). To write future proof code, consult the planned [breaking changes](breaking-changes.md). ## Feature summary ## * A low-level C interface with few assumptions; easy to bind to other languages * Read and write binary and textual headers * Read and write traces and trace headers * Simple, powerful, and native-feeling Python interface with numpy integration * Read and write seismic unix files * xarray integration with netcdf_segy * Some simple applications with unix philosophy ## Getting started ## When segyio is built and installed, you're ready to start programming! Check out the [tutorial](#tutorial), [examples](#examples), [example programs](python/examples), and [example notebooks](https://github.com/equinor/segyio-notebooks). For a technical reference with examples and small recipes, [read the docs](https://segyio.readthedocs.io/). API docs are also available with pydoc - start your favourite Python interpreter and type `help(segyio)`, which should integrate well with IDLE, pycharm and other Python tools. ### Quick start ### ```python import segyio import numpy as np with segyio.open('file.sgy') as f: for trace in f.trace: filtered = trace[np.where(trace < 1e-2)] ``` See the [examples](#examples) for more. ### Get segyio ### A copy of segyio is available both as pre-built binaries and source code: * In Debian [unstable](https://packages.debian.org/source/sid/segyio) * `apt install python3-segyio` * Wheels for Python from [PyPI](https://pypi.python.org/pypi/segyio/) * `pip install segyio` * Source code from [github](https://github.com/equinor/segyio) * `git clone https://github.com/statoil/segyio` * Source code in [tarballs](https://github.com/equinor/segyio/releases) ### Build segyio ### To build segyio you need: * A C99 compatible C compiler (tested mostly on gcc and clang) * A C++ compiler for the Python extension, and C++11 for the tests * [CMake](https://cmake.org/) version 2.8.12 or greater * [Python](https://www.python.org/) 2.7 or 3.x. * [numpy](http://www.numpy.org/) version 1.10 or greater * [setuptools](https://pypi.python.org/pypi/setuptools) version 28 or greater * [setuptools-scm](https://pypi.python.org/pypi/setuptools_scm) * [pytest](https://pypi.org/project/pytest) To build the documentation, you also need [sphinx](https://pypi.org/project/Sphinx) To build and install segyio, perform the following actions in your console: ```bash git clone https://github.com/equinor/segyio mkdir segyio/build cd segyio/build cmake .. -DCMAKE_BUILD_TYPE=Release -DBUILD_SHARED_LIBS=ON make make install ``` `make install` must be done as root for a system install; if you want to install in your home directory, add `-DCMAKE_INSTALL_PREFIX=~/` or some other appropriate directory, or `make DESTDIR=~/ install`. Please ensure your environment picks up on non-standard install locations (PYTHONPATH, LD_LIBRARY_PATH and PATH). If you have multiple Python installations, or want to use some alternative interpreter, you can help cmake find the right one by passing `-DPYTHON_EXECUTABLE=/opt/python/binary` along with install prefix and build type. To build the matlab bindings, invoke CMake with the option `-DBUILD_MEX=ON`. In some environments the Matlab binaries are in a non-standard location, in which case you need to help CMake find the matlab binaries by passing `-DMATLAB_ROOT=/path/to/matlab`. #### Developers #### It's recommended to build in debug mode to get more warnings and to embed debug symbols in the objects. Substituting `Debug` for `Release` in the `CMAKE_BUILD_TYPE` is plenty. Tests are located in the language/tests directories, and it's highly recommended that new features added are demonstrated for correctness and contract by adding a test. All tests can be run by invoking `ctest`. Feel free to use the tests already written as a guide. After building segyio you can run the tests with `ctest`, executed from the build directory. Please note that to run the Python examples you need to let your environment know where to find the Python library. It can be installed as a user, or on adding the segyio/build/python library to your pythonpath. ## Tutorial ## All code in this tutorial assumes segyio is imported, and that numpy is available as np. ```python import segyio import numpy as np ``` This tutorial assumes you're familiar with Python and numpy. For a refresh, check out the [python tutorial](https://docs.python.org/3/tutorial/) and [numpy quickstart](https://docs.scipy.org/doc/numpy-dev/user/quickstart.html) ### Basics ### Opening a file for reading is done with the `segyio.open` function, and idiomatically used with context managers. Using the `with` statement, files are properly closed even in the case of exceptions. By default, files are opened read-only. ```python with segyio.open(filename) as f: ... ``` Open accepts several options (for more a more comprehensive reference, check the open function's docstring with `help(segyio.open)`. The most important option is the second (optional) positional argument. To open a file for writing, do `segyio.open(filename, 'r+')`, from the C `fopen` function. Files can be opened in *unstructured* mode, either by passing `segyio.open` the optional arguments `strict=False`, in which case not establishing structure (inline numbers, crossline numbers etc.) is not an error, and `ignore_geometry=True`, in which case segyio won't even try to set these internal attributes. The segy file object has several public attributes describing this structure: * `f.ilines` Inferred inline numbers * `f.xlines` Inferred crossline numbers * `f.offsets` Inferred offsets numbers * `f.samples` Inferred sample offsets (frequency and recording time delay) * `f.unstructured` True if unstructured, False if structured * `f.ext_headers` The number of extended textual headers If the file is opened *unstructured*, all the line properties will will be `None`. ### Modes ### In segyio, data is retrieved and written through so-called *modes*. Modes are abstract arrays, or addressing schemes, and change what names and indices mean. All modes are properties on the file handle object, support the `len` function, and reads and writes are done through `f.mode[]`. Writes are done with assignment. Modes support array slicing inspired by numpy. The following modes are available: * `trace` The trace mode offers raw addressing of traces as they are