SarPy is a basic Python library to read, write, display, and do simple processing of complex SAR data using the NGA SICD format. It has been released by NGA to encourage the use of SAR data standards throughout the international SAR community. SarPy complements the SIX library (C++) and the MATLAB SAR Toolbox, which are implemented in other languages but have similar goals.

Some sample SICD files can be found here.

In addition to SICD, SarPy can also read COSMO-SkyMed, RADARSAT-2, Radar Constellation Mission (RCM), and Sentinel-1 SLC formats and convert them to SICD.

Some examples of how to read complex SAR data using SarPy are provided in docs/


SarPy was developed at the National Geospatial-Intelligence Agency (NGA). The software use, modification, and distribution rights are stipulated within the MIT license.


The core library functionality depends only on numpy >= 1.9.0 with some very minor dependency on scipy. Support for reading Cosmo-Skymed data (contained in hdf5 files) requires the h5py package.

Python 2.7

The development here has been geared towards Python 3.6 and above, but efforts have been made towards remaining compatible with Python 2.7. If you are using the library from Python 2.7, there is an additional dependency for the typing package, easily installed using conda or pip.

For the new GUI capabilities described below, you additionally need pillow and matplotlib, as well as the future package (not to be confused with the more widely known futures), all of which can be installed using conda or pip.

Breaking Changes - March 2020

In March 2020, the sarpy library has undergone a complete refactor, and the most profound changes have occurred around the particulars of the SICD meta-data structure (a completely object-oriented approach has been adopted), and some of the particulars for the file reading and writing.

The intent of this effort is to provide better long-term stability, and additional capabilities and functionality. Unfortunately, changing the inner workings of the SICD data structure is almost certain to contain some breaking changes for particular uses.

Please do not hesitate to contact for assistance

Associated GUI Capabilities moved to individual repositories - June 2020

In addition to a complete refactor of the core capabilities, graphical user interface functionality were first introduced in March 2020. In June 2020, these capabilities were split out of the sarpy repository into their own repositories in the NGA project. See the sarpy_apps, which depends on tk_builder.


The documentation of this project is a work in progress, particularly for the new GUI efforts. It is the desire for the documentation to be hosted someplace appropriate in the near future.

Currently, basic documentation can be built after checking out this repository using sphinx via the command python build_sphinx. This depends on python packages sphinx and sphinxcontrib-napoleon.

Issues and Bugs

The core sarpy functionality has been tested for Python 2.7.17, 3.6, 3.7, and 3.8. Other versions should be considered unsupported. The new GUI capabilities have been less extensively tested, and should be considered experimental at this point.

Information regarding any discovered bugs would be greatly appreciated, so please feel free to create a github issue.

Pull Requests

Efforts at direct contribution to the project are certainly welcome, and please feel free to make a pull request. The only caveat is that all contributions to this project will be released under the MIT license.

Software source code previously released under an open source license and then modified by NGA staff is considered a "joint work" (see 17 USC 101); it is partially copyrighted, partially public domain, and as a whole is protected by the copyrights of the non-government authors and must be released according to the terms of the original open source license.