Accessing Sentinel Data

Copernicus Open Access Hub

• Description: Provides free access to Sentinel satellite data from the European Space Agency (ESA).
• Access: Users can search, view metadata, and download Sentinel-1, Sentinel-2, and Sentinel-3 data products.
• Usage: Suitable for direct download and integration into local processing workflows.

Google Earth Engine

• Description: Cloud-based platform for planetary-scale geospatial analysis.
• Access: Offers access to Sentinel satellite data along with other Earth observation datasets.
• Usage: Users can perform analysis using JavaScript or Python APIs without needing to download the data locally.
• Features: Supports temporal and spatial filtering, image compositing, and application of algorithms at scale.

Data Preprocessing Steps

• Atmospheric Correction: Adjusting for atmospheric effects using algorithms like Sen2Cor for Sentinel-2 data.
• Geometric Correction: Ensuring images are correctly aligned spatially using precise geometric models.
• Data Fusion: Integrating multiple sensor images to enhance spatial and spectral resolution.
• Quality Assessment: Checking metadata for data quality indicators like cloud cover percentage or sensor calibration status.

Practical Considerations

• Band Selection: Choosing relevant spectral bands (e.g., NIR, SWIR) for specific analysis tasks (e.g., vegetation monitoring).
• Temporal Analysis: Leveraging Sentinel's frequent revisit times for time-series analysis of land use changes.
• Integration with Tools: Using Python libraries like sentinelsat for programmatic access and rasterio for data manipulation.