Key Details

• The least processed of Hydrosat's available imagery products

• Pixel values represent at-sensor radiance in scaled units of W/m²/sr/µm

• Preserves the native spatial resolution and swath of each sensor

• Includes essential instrument-level corrections and georegistration

• Nighttime LWIR data available

Level-1A products are available in three STAC collections: daytime VNIR, daytime LWIR, and nighttime LWIR. You can access and explore these collections via either the (using the Collection dropdown) or the .

Each Level-1A item includes multiple STAC assets, including one cloud-optimized GeoTIFF (COG) for each spectral band.

The ancillary metadata file includes, among other information, the coefficients that a user would need to convert radiance values to reflectance or brightness temperature.

• VNIR radiance values can be converted to top-of-atmosphere reflectance by applying the per-band LEVEL1_REFLECTANCE_SCALING coefficient.

• LWIR radiance values can be converted to brightness temperature as BT = K₂/ln(K₁/L+1), where K₁ and K₂ are per-band LEVEL1_THERMAL_CONSTANTS and L represents scaled radiance.

Only the most essential onboard and ground processing steps are applied at Level-1A. These include:

• Time delay integration (TDI) to combine multiple measurements and produce a cleaner image

• Non-uniformity correction to reduce variations in detector response

• Band coregistration to align the spectral bands within each sensor

• Georegistration to assign each pixel a geographic location

Key Details

• Builds on Level-1A with additional radiometric and geometric processing

• Pixel values represent top-of-atmosphere (TOA) reflectance and brightness temperature

• VNIR and LWIR data are co-registered and aligned on a common 30 m grid

• Nighttime LWIR data available

Level-1B products are distributed in two separate STAC collections to reflect differences in acquisition mode. The first collection includes both VNIR and thermal data from daytime acquisitions, while the second includes only thermal data from nighttime acquisitions.

You can access and explore these collections via either the or the .

Each Level-1B item includes multiple STAC assets, including cloud-optimized geoTIFFs (COGs) along with ancillary metadata and quality information.

The ancillary metadata file includes coefficients for converting Level-1B values back to radiance.

• VNIR reflectance values can be converted to radiance by applying the per-band LEVEL1_RADIANCE_SCALING coefficient.

• LWIR brightness temperature values can be converted to radiance as L = K₁/(e(K₂/BT)-1), where K₁ and K₂ are per-band LEVEL1_BT_TO_RADIANCE_CONSTANTS.

At Level-1B, we apply additional radiometric and geometric processing. These steps include:

• Conversion of radiance to TOA reflectance and brightness temperature

• Co-registration of VNIR and LWIR imagery on a common 30 m grid

• Orthorectification using a digital elevation model to improve geometric accuracy

• Cloud mask generation for identifying cloudy pixels

Key Details

• Our highest-level imagery product

• Pixel values represent surface reflectance (SR) and land surface temperature (LST)

• Includes atmospheric, terrain, and surface corrections

• Best suited for environmental monitoring and scientific analysis

A single Level-2 STAC collection is available. You can access and explore this collection via either the or the .

All of the following assets are available for every Level-2 item, since Level-2 products are distributed in a single STAC collection.

At Level-2, we apply the processing needed to derive surface reflectance and land surface temperature. This is an involved sequence that includes:

• Radiometric terrain correction to account for terrain-induced illumination effects

• Surface reflectance retrieval from TOA reflectance

• LST estimation from TOA brightness temperatures with emissivity correction

• Per-pixel LST uncertainty estimation based on radiometric, emissivity, atmospheric, and algorithm uncertainties