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Data Gateway Building Block⚓︎

Introduction⚓︎

The Data Gateway Building Block provides a consolidated and consistent capability for accessing Earth Observation data from an extensible set of providers and datasets. Unlike other EOEPCA building blocks that require deployment, the Data Gateway is implemented through EODAG (Earth Observation Data Access Gateway) - a Python library and command-line tool that other components integrate directly.

Architecture⚓︎

The Data Gateway acts as an abstraction layer between EOEPCA components and various data providers. It presents a unified interface (including STAC semantics) regardless of the underlying data source, eliminating the need for each building block to implement provider-specific logic.

Key Capabilities: - Unified API for 50+ product types across 10+ providers - Plugin architecture supporting STAC, OpenSearch, OData, and custom protocols - Automatic handling of authentication and data retrieval - Extensible to support new providers via configuration or plugins

Integration with EOEPCA⚓︎

The Data Gateway is utilised by other building blocks rather than deployed standalone:

  • Resource Registration: Uses Data Gateway for harvesting from external catalogues
  • Processing Engine: Leverages it for input data preparation and access
  • Data Access: Employs it for retrieving dataset assets for visualisation services

Configuration⚓︎

Basic Setup⚓︎

  1. Install EODAG: 

    pip install eodag

  2. Configure Provider Credentials:

EODAG automatically creates a configuration file at ~/.config/eodag/eodag.yml on first run. Add your provider credentials:

providers:
  cop_dataspace:
    auth:
      credentials:
        username: your_username
        password: your_password

Usage Example⚓︎

Python Integration⚓︎

from eodag import EODataAccessGateway

# Initialise EODAG
dag = EODataAccessGateway()

# Search for Sentinel-2 products
search_results = dag.search(
    collection='S2_MSI_L1C',
    geom={'lonmin': 1, 'latmin': 43.5, 'lonmax': 2, 'latmax': 44},
    start='2021-01-01',
    end='2021-01-15',
    provider='cop_dataspace'  # Optional: specify provider
)

# Download all results
product_paths = dag.download_all(search_results)

# Or download specific item
if search_results:
    first_product = search_results[0]
    path = dag.download(first_product)
    print(f"Downloaded to: {path}")

Command Line Interface⚓︎

# List available product types
eodag list

# Search for products
eodag search --productType S2_MSI_L1C \
  --box 1 43 2 44 \
  --start 2021-01-01 --end 2021-01-15

# Download search results
eodag download --search-results search_results.geojson

Supported Providers⚓︎

EODAG comes pre-configured with many providers including: - Copernicus Data Space - AWS/GCS (Sentinel on cloud storage) - CREODIAS, Mundi, ONDA, WEkEO (DIAS platforms) - USGS (Landsat products) - Destination Earth Data Lake

View the complete list and their configurations in the EODAG Providers Documentation.

Extending EODAG⚓︎

Add custom providers by creating a configuration:

my_custom_provider:
  search:
    type: StacSearch
    api_endpoint: https://my-stac-api.com
  products:
    S2_L2A:
      productType: sentinel-2-l2a

Further Resources⚓︎