Level-1C Product Formatting

Sentinel-2 Level-1C is an orthoimage product, i.e. a map projection of the acquired image using a system DEM to correct ground geometric distortions. Pixel radiometric measurements are provided in Top-Of-Atmosphere (TOA) reflectances (coded in 12 bits) with all parameters to transform them into radiances.

Level-1C products are resampled with a constant GSD (Ground Sampling Distance) of 10 m, 20 m and 60 m according to the native resolution of the different spectral bands.

Level-1C products are routinely geometrically refined. However, they can be processed without refinement on an "as required" basis (e.g. where they might be required for cal/val purposes). These products can be identified by the presence of a dedicated flag in the metadata.

Level-1C processing includes:

  • geometric corrections:
    • sub-pixel multi-temporal registration between images
    • resampling using a 90m DEM (PlanetDEM 90)
  • radiometric processing
    • conversion to reflectance
  • preview image generation and masks generation (defective pixels, clouds and land/water).

One single Level-1C product always refers to one datatake and may cover the full datatake or an extract of it covering the user's area of interest.

The Level-1C image corresponds to a set of tiles. A tile is a 100 km by 100 km squared orthoimage in UTM/WGS84 projection. There is one tile per spectral band. All tiles intersecting the users Area Of Interest (AOI) and covering one data-take are provided in the final Level-1C product.

Figure 1: Example of Level-1C Tiled Product

The quality indicator and the auxiliary data are provided within the metadata.

Note that one Level-1C tile including all bands is approximately 500 MB in file size.

Data Information
Metadata Product Level and tiles
Image data Collection of elementary tiles (i.e. set of raster files compressed using JPEG2000 algorithm), 1 tile = 100 km x 100 km squared orthoimage
Quality indicators data derived from Level-1B and Level-1C: radiometric quality, geometric quality, image content quality, quality control checks information
Auxiliary data used GIPP and used DEM and GRI references + meteorological ECMWF parameters (Total Column Ozone (TCO3), Total Column Water Vapour (TCWV) and Mean Sea Level Atmospheric Pressue (MSLP))

Table 1: Level-1C product content

Reference Document: GMES-GSEG-EOPG-TN-09-0029 (v2.3) | ESA document

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