Sentinel-2 - Downloading, Conversion to L2A (reflectance) and reprojecting
Sentinel-2 is a European Space Agency (ESA) satellite observation program which provides multispectral imagery at 10-60 m resolution with a repeat time of ~5 days.
The obvious way of downloading the data is to use the Copernicus SciHub. However, this method is very slow and often downloads time-out before they have finished.
If you are comfortable on the command line then there is a more efficient way to obtain Sentinel-2 data: Sentinel-Hub. This service is provided by a private company called Sinergise but, at the time of writing, is free of charge.
Use pip to install their command-line interface and Python bindings:
pip install sentinelhub
This package provides a variety of options for downloading Sentinel-2 data from Sentinel-Hub. We are interested in downloading data from their Amazon Web Services interface, so we will use the command line interface called
There are a variety of ways to search for data based on their acquisition date and location. The simplest method, shown here, is to download an image of a single tile for a single date. The Sentinel-2 grid scheme can be found on the ESA website as a KML file.
This example downloads imagery acquired on 2016-06-01 in tile 22WEV:
sentinelhub.aws --tile T22WEV 2016-06-01 -e
The -e flag specifies download of the entire product. The product will be delivered in ESA’s SAFE format, which means we can now convert it from top-of-atmosphere radiance (L1C) to bottom-of-atmosphere reflectance (L2A).
Conversion to L2A (reflectance)
This requires the ESA Sen2Cor processor, which can be found as part of SNAP but is also provided as a standalone program.
Download and install the processor, then process an image to L2A as follows:
This takes a while to complete but produces an L2A image in SAFE format.
This requires GDAL >= 2.1 to be installed in your environment.
GDAL can convert any of the 10 m, 20 m or 60 m sub-datasets into a multi-band geotiff.
In this example, reproject the 10 m subdataset to a North Polar Stereographic (EPSG:3413) geoTIFF:
gdalwarp -t_srs EPSG:3413 SENTINEL2_L2A:S2A_USER_PRD_MSIL2A_PDMC_20160607T020144_R125_V20160605T145923_20160605T145923.SAFE/S2A_USER_MTD_SAFL2A_PDMC_20160607T020144_R125_V20160605T145923_20160605T145923.xml:10m:EPSG_32622 S2A_USER_MTD_SAFL2A_PDMC_20160607T020144_R125_V20160605T145923_20160605T145923_10m_EPSG3413.tif