Operational F-SAR processing chains produce a variety of different data products. The most common product types include:
RGI Focused SAR data in radar geometry
GTC Geocoded SAR data
INF Co-registered image stacks for interferometry
Other data products include SAR imagery from circular acquisitions, polarimetric change detection results, geocoded amplitude mosaics and more.
The structure and contents of these data products is described in the F-SAR Product Description document.
The binary data in F-SAR products is generally stored in the so-called RAT format. In addition, most RAT files are accompanied by .hdr files, which allow the data to be opened in ENVI. The widely used GDAL software library also supports the ENVI format, such that F-SAR data can also be opened using free alternatives such as QGis. Any of these programs can then be used to export F-SAR data to various other file formats, such as GeoTiff.
Native RAT/XML Interface
Researchers developing their own SAR signal processing techniques on the basis of F-SAR data may find it more convenient to read the binary in F-SAR products directly. A direct interface to the data may even be required when the application under consideration involves working with complex data or sensor tracks, as neither data type is well supported by GIS software.
A native interface to F-SAR data is available as part of the PyRAT radar signal processing framework. Researchers may want to consider using PyRAT as a basis for implementing new signal processing algorithms. Alternatively, the F-SAR RAT and XML interface can be downloaded and used separately.
The following basic usage examples assume that ste_io.py has been downloaded and that the python interpreter has been launched in the directory containing the downloaded package.
PyRAT Example 1
The rrat function reads the contents of RAT files into NumPy arrays
The rrat function also supports reading blocks of data. The following example reads a block of data spanning rows 1000 to 1199 and columns 500 to 799 of the full array on disk.
In addition, the ste_io.py package defines the Xml2Py class, which facilitates object-like access to parameters stored in the pp*.xml files of the RDP product components. The following example reads a pp file from the RGI-RDP product component and illustrates how parameter values are conveniently accessed as python object properties.
