Preprocessing Sentinel-2 with SNAP

Reading a Sentinel-2 tile

1. Download a complete Sentinel-2 tile from ESA Open Access Hub.
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

We resample the spatial resolution 20m bands to 10m.

1. Raster --> Geometric Operations --> 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

1. Mark the file name of the resampled product from previous work step in Product Explorer.
2. Raster --> Subset..
3. Left click in the preview of the Specify product subset dialog.

• Spatial subset

1. In the Spatial Subset tab draw a box on the preview image and move it to your region of interest.
2. Make a note of the Pixel Coordinates and (Geographical) Geo Coordinates if you want to repeat this step with other acquisiton dates of the same tile.

• Spectral subset

1. In the 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