Preprocessing Sentinel-2 with SNAP

Reading a Sentinel-2 tile

1. Download a complete Sentinel-2 tile from ESA Open Access Hub (see Downloading Sentinel-2 images).
2. Start SNAP Desktop
3. File --> Open Product...) Browse to the compressed Sentinel-2 zip file. Open or drag and drop the zip file from Windows File Explorer into the SNAP Product Explorer tab.
4. Click on the plus sign of the file name in Product Explorer. Unfold Metadata and Bands.

Displaying a Sentinel-2 tile

1. Mark the file name in the Product Explorer. Right click Open RGB Image Window). In the Profile drop-down list select Sentinel 2 MSI False Colour Infrared. OK

Resampling

The spatial resolution of all satellite bands should be resampled to a unique pixel size (10m) to simplify the processing workflow. Raster --> Geometric --> Resampling. Open the Resampling Parameters tab. Define size of resampled product: check by reference band from source product. Select B2 from drop down list. Run.

Subsetting

Spatial subset

• Mark the file name of the resampled product from previous work step in Product Explorer.
• Raster --> Subset..
• Left click in the preview of the Specify product subset dialog.
• In the Spatial Subset tab draw a box on top of the preview image and move it to your region of interest.
• Make a note of Pixel Coordinates and (Geographical)' Geo Coordinates if you want to repeat this step with other acquisiton dates of the same tile.

Spectral subset

• In Band Subset tab click Select none and then check only the multispectral Reflectance Bands (B2,B3,B4,B5,B6,B7,B8,B8A,B11,B12). OK.

Write to permanent file

Mark the subset file name in Product Explorer. File --> Export --> GeoTIFF. Click Export Product.