4.4.7. Sentinel-3

_images/sentinel3_tab.jpg

sentinel3_tool Sentinel-3

This tab allows for the conversion of Sentinel-3 images (OL_1_EFR) to the physical measure of Top Of Atmosphere reflectance (TOA), or the application of a simple atmospheric correction using the DOS1 method (Dark Object Subtraction 1), which is an image-based technique (for more information about conversion to TOA and DOS1 correction, see Image conversion to reflectance). The following ancillary data are required for conversion: instrument_data.nc , geo_coordinates.nc , tie_geometries.nc .

Once the input is selected, available bands are listed in the metadata table.

WARNING: Sentinel-3 bands are reprojected to WGS 84 coordinate system using a sample of pixels from the file geo_coordinates.nc . For the best precision you should use the official SNAP tool (see http://step.esa.int).

4.4.7.1. Sentinel-3 conversion

  • Directory containing Sentinel-3 bands open_dir: open a directory containing Sentinel-3 bands; names of Sentinel-2 bands must end with the corresponding number; ancillary data required for conversion must be in the same directory;

  • checkbox Apply DOS1 atmospheric correction: if checked, the DOS1 Correction is applied to all the bands;

  • checkbox Use value as NoData input_number: if checked, pixels having NoData value are not counted during conversion and the DOS1 calculation of DNmin; it is useful when image has a black border (usually pixel value = 0);

  • checkbox Create Band set and use Band set tools: if checked, bands are added to the active Band set after the conversion; also, the Band set is processed according to the tools checked in the Band set;

  • checkbox Add bands in a new Band set: if checked, bands are added to a new empty Band set after the conversion;

4.4.7.2. Metadata

All the bands found in the Directory containing Sentinel-3 bands are listed in the table Metadata.

  • Satellite input_text: satellite name (e.g. Sentinel-3A);

  • Product input_text: product name (e.g. OLCI);

  • remove: remove highlighted bands from the table Metadata;

  • input_table Metadata: table containing the following fields;

    • Band: band name;

  • BATCH batch_tool: add this function to the Batch;

  • RUN run: select an output directory and start the conversion process; only bands listed in the table Metadata are converted; converted bands are saved in the output directory with the prefix RT_ and automatically loaded in QGIS;