Raw radar measurement of ground shift (NISAR, beta)
What it measures. Maps of how far the ground appears to have shifted between two radar passes, measured pixel by pixel in two directions. The numbers are raw and unfiltered, so they still include noise and bad values.
How it's made. Built by NISAR's radar by comparing two roughly aligned snapshots of the same area and tracking how features moved between them, with no clean-up applied.
How & where you'd use it. This is a beta, raw building-block product meant to let people get familiar with the data format rather than for real research; ground-shift information usually reaches users through cleaner, higher-level products.
What's measured
Coverage & cadence
- Time span2025-10-01 → ongoing
- Measured byNISAR (L-SAR, S-SAR)
- Processing levelLevel 1
- Spatial extent-180, -90, 180, 90
- FormatsHDF5, XML, YAML, PNG, KML, CSV, PDF
- StatusACTIVE
What you can do with it
- Track deforestation, fire scars and land-cover change
- Monitor crop and vegetation health (NDVI/EVI)
- Map how built-up vs. green an area is over time
Official description
The NASA-ISRO Synthetic Aperture Radar (NISAR) Range Doppler Pixel Offsets (ROFF) product contains a collection of dense pixel offset layers obtained from applying incoherent cross-correlation on a pair of coarsely coregistered Level 1 Range Doppler Single Look Complex (RSLC) products in the range-Doppler geometry of the earlier reference RSLC product. The pair of RSLCs used to produce ROFF is first coarsely aligned with geometrical coregistration using the best available sensor orbit ephemeris and a Digital Elevation Model (DEM). The spacing, the window size, and the search radius used to generate the ROFF offsets layers for L-SAR data are organized by sensor mode and area of observation. Irrespective of the mode, the pixel offset layers are provided with a nominal posting of 90 m on the ground. It is assumed that pixel offset layers within ROFF share the same spacing and the same starting pixel along slant range and azimuth directions. Each pixel offset layer is distributed without performing any conventional post-processing operation, i.e., layers might contain offset outliers and are not low-pass filtered to reduce noise in the data. The products in this collection are considered Beta products and are intended to enable users to gain familiarity with the parameters and the data formats. Beta products are not intended for use in scientific research.
Get the data
import earthaccess
earthaccess.login(strategy="netrc") # free Earthdata Login
results = earthaccess.search_data(
short_name="NISAR_L1_ROFF_BETA_V1",
version="1",
bounding_box=(-122.5, 37.2, -121.8, 37.9), # your area (W,S,E,N)
temporal=("2024-01-01", "2024-12-31"), # your dates
)
files = earthaccess.open(results) # stream straight from ASFBrowsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.