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Using NISAR Data In CATALYST Professional

The NASA-ISRO Synthetic Aperture Radar (NISAR) mission is a joint Earth observation initiative between NASA and ISRO to provide high-resolution, all-weather, time-independent measurements. Equipped with dual-frequency SAR (L- and S-bands), NISAR enables monitoring of a wide range of environmental processes, including land deformation, vegetation dynamics, ice sheet movement, natural hazards, and ecosystem change.

NISAR provides global, systematic coverage with frequent revisit times, enabling consistent monitoring of Earth's land and ice surfaces. Its dual-frequency synthetic aperture radar (L-band and S-band) enhances sensitivity to vegetation structure, surface deformation, and a wide range of land-cover types, making it suitable for diverse environmental and hazard-monitoring applications. The mission's consistent observation strategy supports long-term change detection and time-series analyses. In addition, NISAR data is openly and freely available, promoting widespread use by researchers, government agencies, and industry for scientific research and operational decision-making.

NASA/JPL-Caltech: NISAR Views Portland

As of version 3.4.0, CATALYST Professional supports the L-band Radar Single Look Complex (RSCL) Level 1 product, including single-, dual-, and quad- polarization datasets.

Table of Contents

Ingesting NISAR Data

Before NISAR imagery can be used in CATALYST, the native metadata must first be mapped into CATALYST Earth standard metadata. This conversion is performed using the SARINGEST algorithm. The key file to be used is the NISAR_L1_PR_RSLC*.h5 file, which contains the imager, metadata, and acquisition information required for processing. In addition to the keyfile, a NISAR swath must be included in the path to form the complete input data string. NISAR data comes with up to two swaths - FrequencyA and FrequencyB. In SARINGEST, the input data field will have the format:
\path-to-data\NISAR_L1_PR_RSLC*.h5?SPID=<swath-name>,
where swath-name is one of NISAR_L1_RSLC_FREQ_A or NISAR_L1_RSLC_REQ_B.
The resulting PCIDSK file can then be used in subsequent CATALYST workflows.

In Focus

To ingest NISAR data in Focus:

  1. Open the Algorithm Librarian: Focus > Tools > Algorithm Librarian...
  2. Navigate to the SARINGEST algorithm.
  3. In the Output Ports section, select Browse...
  4. Navigate to the output folder and enter a file name.
  5. Click Run.
Using The CATALYST Professional Python API

NISAR can be ingested using the CATALYST Professional Python API through the following script:

from pci.saringest import saringest

fili = r'H:\Tutorials\NISAR\L1-RSLC-001\NISAR_L1_PR_RSLC_001_030_A_019_2000_SHNA_A_20081012T060910_20081012T060926_D00402_N_F_J_001.h5?SPID=NISAR_L1_RSLC_FREQ_A'
filo = r'H:\Tutorials\NISAR\L1-RSLC-001\NISAR_L1_PR_RSLC_001_030_A_019_2000_SHNA_A_20081012T060910_20081012T060926_D00402_N_F_J_001.pix'
dbiw = []
poption = 'NEAR'
dblayout = 'BAND'
calibtyp = 'SIGMA'

saringest(fili, filo, dbiw, poption, dblayout, calibtyp)

Visualizing NISAR Data In Focus

Phase & Coherence

To view NISAR data as phase and coherence:

  1. In the Files tab in Focus, open the ingested NISAR pix file.
  2. Expand the Rasters segment and then right-click on a channel.
    • Select View > As Amplitude and Phase.
  3. In the Maps tab, right-click the image and open the Layer Properties.
  4. Navigate to the Display tab and adjust the Phase percent slider accordingly:
    • View as Phase = 100
    • View as Coherence = 0
NISAR image viewed as Phase in CATALYST Professional - Focus
NISAR image viewed as Coherence in CATALYST Professional - Focus

Processing NISAR Data With CATALYST Professional

Once the NISAR data has been ingested in CATALYST, it can be used in a wide range of SAR processing workflows, including radiometric calibration, speckle filtering, change detection, and more. For a step-by-step example of a SAR change detection workflow, see the Change Detection For SAR tutorial.

Processing NISAR Data With CATALYST INSIGHTS

For organizations looking to operationalize NISAR data, we offer CATALYST INSIGHTS, a service that transforms NISAR and other Earth observation data into actionable insights. If you have an upcoming project and would like to explore how NISAR data can support your objectives, we'd be happy to discuss your requirements. Learn more about CATALYST INSIGHTS at https://catalyst.earth/solutions/catalyst-insights/.

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