Product Details

Learn more about the different data products Hydrosat provides.

Level-1 Imagery

The Level-1A data product is the least processed of the available imagery. It includes processing applied onboard the instrument, such as time delay integration and non-uniformity corrections, as well as co-registration of sensor bands and georegistration. The full swath data is provided to users in image space with no resampling. Coefficients needed to convert digital number (DN) values to radiance are available in metadata.

The Level-1B product includes clipping the VIRI data to the extent of the LIRI swath, generation of a cloud mask, and orthorectification.

L1 Product Granule Size

L1A VIRI: 122 km x 70 km

L1A LIRI: 70 km x 70 km

L1B: Combined 70 km x 70 km

L1 Pixel Size

L1A VIRI: 29.9 m

L1A LIRI: 68.8 m

L1B: 30 m

Resampling Method

Bilinear (L1B only)

Bit Depth

16-bit

Map Projection

L1A VIRI & LIRI: EPSG 4326 (RPCs included in metadata)

L1B: Universal Transverse Mercator (UTM)

No Data Value

0

Radiometric Rescaling

Per-band gain and offset for conversion from DN to radiance and at-sensor reflectance included in metadata

Level-1 Assets

Each STAC item includes several assets representing the individual data and metadata files associated with the scene. Items from different collections contain a different set of assets, as defined below.

vz-viri-l1a
Asset
Description
Center Wavelength (nm)
File Type

BLUE

Blue band digital number (DN) values

490.5

COG

GREEN

Green band DNs

560.5

COG

RED

Red band DNs

665

COG

REDEDGE1

Red edge 1 band DNs

705.5

COG

REDEDGE2

Red edge 2 band DNs

740.5

COG

REDEDGE3

Red edge 3 band DNs

783

COG

NIR

NIR band DNs

842.5

COG

QUALITY_ASSURANCE

Radiometric saturation mask

COG

PREVIEW

Full-resolution RGB preview image

COG

THUMBNAIL

Low-resolution RGB thumbnail

PNG

METADATA

Ancillary metadata file

JSON

vz-liri-l1a
Asset
Description
Center Wavelength (µm)
File Type

LWIR1

LWIR 1 band digital number (DN) values

10.895

COG

LWIR2

LWIR 2 band DNs

12.005

COG

QUALITY_ASSURANCE

Radiometric saturation mask

COG

PREVIEW_LWIR

Full-resolution LWIR preview image

COG

THUMBNAIL

Low-resolution thumbnail

PNG

METADATA

Ancillary metadata file

JSON

vz-l1b
Asset
Description
File Type

BLUE

Blue band digital number (DN) values

COG

GREEN

Green band DNs

COG

NIR

NIR band DNs

COG

RED

Red band DNs

COG

REDEDGE1

Red edge 1 band DNs

COG

REDEDGE2

Red edge 2 band DNs

COG

REDEDGE3

Red edge 3 band DNs

COG

LWIR1

LWIR 1 band DNs

COG

LWIR2

LWIR 2 band DNs

COG

QUALITY_ASSURANCE

Radiometric saturation mask

COG

CLOUD_MASK

Mask indicating cloud, cloud shadow, and snow or ice

COG

PREVIEW

Full-resolution RGB preview image

COG

PREVIEW_LWIR

Full-resolution LWIR preview image

COG

THUMBNAIL

Low-resolution RGB thumbnail

PNG

METADATA

Ancillary metadata file

JSON

Level-2 Imagery

The Level-2 product includes radiometric terrain corrections and conversion to surface reflectance (SR) and land surface temperature (LST).

L2 Product Granule Size

70 km x 70 km

L2 Pixel Size

30 m

Map Projection

UTM

Bit Depth

16-bit

No Data Value

0

Scaling Factor

LST, LST uncertainty, BT: 0.01

SR, emissivity: 0.0001

Level-2 Assets

Level-2 assets include per-band SR and LST COGs (and more).

vz-l2
Asset
Description
File Type

BLUE_SR

Blue band surface reflectance

COG

GREEN_SR

Green band surface reflectance

COG

NIR_SR

NIR band surface reflectance

COG

RED_SR

Red band surface reflectance

COG

REDEDGE1_SR

Red edge 1 band surface reflectance

COG

REDEDGE2_SR

Red edge 2 band surface reflectance

COG

REDEDGE3_SR

Red edge 3 band surface reflectance

COG

LWIR1_BT

LWIR 1 band brightness temperature

COG

LWIR2_BT

LWIR 2 band brightness temperature

COG

LWIR1_EMIS

LWIR 1 band emissivity

COG

LWIR2_EMIS

LWIR 2 band emissivity

COG

LST

Land surface temperature

COG

LST_UNCERTAINTY

Land surface temperature uncertainty

COG

QUALITY_ASSURANCE

Radiometric saturation mask

COG

CLOUD_MASK

Mask indicating cloud, cloud shadow, and snow or ice

COG

PREVIEW

Full-resolution RGB preview image

COG

PREVIEW_LST

Full-resolution LST preview image

COG

THUMBNAIL

Low-resolution RGB thumbnail

PNG

THUMBNAIL_LST

Low-resolution LST thumbnail

PNG

METADATA

Ancillary metadata file

JSON

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