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Full catalog/VJ203IMG
VJ203IMG·v2.1·dataset

Pixel location helper file (NOAA-21, 375 m)

VIIRS/JPSS2 Imagery Resolution Terrain-Corrected Geolocation 6-Min L1 Swath 375m V2.1
land NASA LAADS Level 1A active netCDF-4
In plain English

What it measures. The precise Earth location of every image pixel, plus details like surface height, sun and sensor angles, and a land-versus-water flag for each spot.

How it's made. Generated for the VIIRS instrument on the NOAA-21 satellite using the satellite's position and orientation along with Earth and terrain models to pin down where each pixel falls.

How & where you'd use it. A behind-the-scenes helper file that other VIIRS products rely on to know exactly where each measurement is on the globe; not used on its own.

What's measured

SPECTRAL/ENGINEERING › INFRARED WAVELENGTHS › INFRARED RADIANCESPECTRAL/ENGINEERING › INFRARED WAVELENGTHS › REFLECTED INFRAREDSPECTRAL/ENGINEERING › SENSOR CHARACTERISTICS › GEOLOCATIONSPECTRAL/ENGINEERING › VISIBLE WAVELENGTHS › VISIBLE RADIANCE

Coverage & cadence

  • Time span2023-02-10 → ongoing
  • Measured byNOAA-21 (VIIRS)
  • Processing levelLevel 1A
  • Spatial extent-180, -90, 180, 90
  • FormatsnetCDF-4
  • 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 VIIRS/JPSS2 Imagery Resolution Terrain Corrected Geolocation 6-Min L1 Swath 375 m, short-name VJ203IMG is the Joint Polar-orbiting Satellite System-2 (JPSS-2/NOAA-21) platform-derived NASA Visible-Infrared Imaging-Radiometer Suite (VIIRS) L1 terrain-corrected geolocation product and contains the derived line-of-sight (LOS) vectors for each of the 375-m image-resolution or I-bands. The geolocation algorithm uses a number of inputs that include an Earth ellipsoid, geoid, and a digital terrain model along with the SNPP platform’s ephemeris and attitude data, and knowledge of the VIIRS sensor and satellite geometry. It produces geodetic coordinates (latitude and longitude), and related parameters for each VIIRS L1 pixel. The VJ203IMG product includes geodetic latitude, longitude, surface height above the geoid, solar zenith and azimuth angles, sensor zenith and azimuth angles, land/water mask, and quality flag for every pixel location. VJ203IMG provides a fundamental input to derive a number of VIIRS I-band higher-level products. The J2 VIIRS geolocation underwent an on-orbit validation. Geolocation errors of about 350 m in the along-scan direction and about 165 m in the along-track direction were corrected for the image-resolution bands and moderate-resolution bands. The Day-Night band (DNB) geolocation error of about 2000 m was corrected. Further, the geolocation biases in the scan profile were also corrected.

Get the data

vj203img_access.py
import earthaccess
earthaccess.login(strategy="netrc")          # free Earthdata Login

results = earthaccess.search_data(
    short_name="VJ203IMG",
    version="2.1",
    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 LAADS
Browsing CMR needs no login. Downloading or streaming bytes needs a free Earthdata Login + the earthaccess package.