Introducing Sarpy 2.0 !
SarPy 2.0
SarPy 2.0 is a merge between the sarkit library, which is the new NGA standards libary, and legacy SarPy functions. This initial release introduces the SARKit fast readers which use SARKit to read standard NGA File Formats and includes handy functions in the reader object itself. You can use the fast readers by doing the following import:
from sarpy.io.sarkitFastReader import FastReadSICD
There are fast read options for SICD, SIDD, CPHD, and CRSD. You can use the python help function to access the reader parameters. The SICD fast reader includes methods to perform projections and remaps. The legacy sarpy readers for NGA standards have been deprecated in favor of the fast readers. Feedback is welcome!
SarPy
SarPy is a basic Python library to read, write, and do simple processing of complex SAR data using the NGA SICD format (standards linked below). 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.
Relevant Standards Documents
A variety of SAR format standard are mentioned throughout this ReadMe, here are associated references.
Sensor Independent Complex Data (SICD) - latest version (1.3.0; 2021-11-30)
- Volume 1, Design & Implementation Description Document
- Volume 2, File Format Description Document
- Volume 3, Image Projections Description Document
- Schema
Sensor Independent Derived Data (SIDD) - latest version (3.0; 2021-11-30)
- Volume 1, Design and Implementation Description Document
- Volume 2, NITF File Format Description Document
- Volume 3, GeoTIFF File Format Description Document
- Schema
Compensated Phase History Data (CPHD) - latest version (1.1.0; 2021-11-30)
Both SICD and SIDD files are NITF files following specific guidelines Basic Image Interchange Format (BIFF) - latest edition (2021.2; 2021-04-20)
For other NGA standards inquiries, the standards registry can be searched
here.
Basic Capability
The basic capabilities provided in SarPy is generally SAR specific, and largely geared towards reading and manipulating data provided in NGA SAR file formats. Full support for reading and writing SICD, SIDD, CPHD, and CRSD (standard pending) and associated metadata structures is currently provided, and this is the main focus of this project.
There is additionally support for reading data from complex data formats analogous to SICD format, usually called Single Look Complex (SLC) or Level 1, from a variety of commercial or other sources including
- Capella (partial support)
- COSMO-SkyMed (1st and 2nd generation)
- GFF (Sandia format)
- ICEYE
- NISAR
- PALSAR2
- RadarSat-2
- Radar Constellation Mission (RCM)
- Sentinel-1
- TerraSAR-X.
For this SLC format data, it is read directly as though it were coming from a SICD file. This ability to read does not generally apply to data products other than the SLC or Level 1 product, and there is typically no direct NGA standard analog for these products.
Some general TIFF and NITF reading support is provided, but this is not the main goal of the SarPy library.
Documentation
Documentation for the project is available at readthedocs.
If this documentation is inaccessible, it can be built locally after checking out
this repository using sphinx via the command python setup.py build_sphinx.
This depends on python package sphinx.
Origins
SarPy was developed at the National Geospatial-Intelligence Agency (NGA). The software use, modification, and distribution rights are stipulated within the MIT license.
Dependencies
The core library functionality depends only on numpy and scipy.
Optional Dependencies and Behavior
There are a small collection of dependencies representing functionality which may not be core requirements for much of the sarpy targeted tasks. The tension between requiring the least extensive list of dependencies possible for core functionality and not having surprise unstated dependencies which caused unexpected failures is evident here. It is evident that there are many viable arguments for making any or all of these formally stated dependencies. The choices made here are guided by practical realities versus what is generally considered best practices.
For all packages on this list, the import is tried (where relevant), and any
import errors for these optional dependencies are caught and handled. In other words,
a missing optional dependency will not be presented as import time. Excepting
the functionality requiring h5py, this import error handling is probably silent.
Every module in sarpy can be successfully imported, provided that numpy and scipy are in the environment. Attempts at using functionality depending on a missing optional dependency will generate an error at run time with accompanying message indicating the missing optional dependency.
-
Support for reading single look complex data from certain sources which provide data in hdf5 format require the
h5pypackage, this includes Cosmo-Skymed, ICEYE, and NISAR data. -
Reading an image segment in a NITF file using jpeg or jpeg 2000 compression, reading a GeoTIFF DEM, and/or writing a kmz image overlay requires the
pillowpackage. -
CPHD consistency checks, presented in the
sarpy.consistencymodule, depend onlxml>=4.1.1,networkx>=2.5,shapely>=1.6.4, andpytest>=3.3.2. Note that these are the versions tested for compliance. -
Some less commonly used (in the sarpy realm) NITF functionality requires the use and interpretation of UTM coordinates, and this requires the
pyprojpackage. -
Building sphinx documentation (mentioned below) requires packages
sphinx, andsphinx_gallery. -
Optional portions of running unit tests (unlikely to be of relevance to anyone not performing development on the core sarpy package itself) require the
lxmlpackage
Installation
From PyPI, install using pip (may require escalated privileges e.g. sudo):
pip install sarpy
Note that here pip represents the pip utility for the desired Python environment.
For verbose instructions for installing from source, see
here. It is recommended that
still the package is built locally and installed using pip, which allows a proper
package update mechanism, while python setup.py install does not.
Issues and Bugs
Support for Python 2 has been dropped. The core sarpy functionality has been tested for Python 3.8, 3.9, 3.10, 3.11, 3.12.
Changes to sarpy for the sole purpose of supporting a Python version beyond end-of-life are unlikely to be considered.
Information regarding any discovered bugs would be greatly appreciated, so please feel free to create a GitHub issue. If more appropriate, contact richard.m.naething@nga.mil.
Integration Branches
Integration branches (branches prefixed with integration/) are used to stage content under
consideration for inclusion in the master branch and future SarPy releases.
These branches can be used to access features and bug fixes that have not been fully released.
Pull Requests
Efforts at direct contribution to the project are certainly welcome, and please
feel free to make a pull request. Pull requests should be authored against the master
branch but may be retargeted to a suitable integration branch upon review.
Note that any and 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.
Associated GUI Capabilities
Some associated SAR specific graphical user interface tools are maintained in the sarpy_apps project.
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Metadata
5 maintainers
Release files for sarpy 2.1.1
For a detailed explanation of source distributions (sdists) and built distributions (wheels), please see the package formats documentation.
Source distribution (sdist)
| File | Size | Uploaded | |
|---|---|---|---|
| sarpy-2.1.1.tar.gz | 1.3 MB | Details |
Built distribution (wheel)
| File | Interpreter | ABI | Platform | Reset |
|---|---|---|---|---|
| sarpy-2.1.1-py2.py3-none-any.whl | Python 2, Python 3 | none | any | Details |
Total release size: 2.9 MB
Release files / sarpy-2.1.1.tar.gz
| Download URL | sarpy-2.1.1.tar.gz |
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