Hazard Data Service

The hazard data service integrates with Google Earth Engine (GEE) to provide geospatial hazard layers (e.g., heatwaves, flooding) for map visualization.

Features

1. Layer Configuration

The /api/v1/hazards/layer-config endpoint returns the metadata for all supported hazard layers, including:

• Available scenarios (e.g., historical, SSP126, SSP245, SSP370, SSP585)
• Year ranges for projected data
• Color scales (palettes) and legends
• Data source information (e.g., NASA NEX-GDDP-CMIP6, WRI Aqueduct)

2. Geospatial Data Retrieval

The /api/v1/hazards/{hazard_type} endpoint retrieves the specific Earth Engine asset for a hazard. It handles:

• Scenarios: Filtering by climate scenario (e.g., Historical, SSP245, SSP585).
• Time Periods: Selecting the appropriate year range for projected data.
• Tiling: Providing a tile_url format for the frontend to render GEE tiles directly.

EarthEngineClient

The EarthEngineClient handles initialization and communication with the Google Earth Engine Python API.

Authentication

The service initializes the Earth Engine client using the Google Cloud Project ID configured in the environment:

• It uses the default application credentials (ADC) available in the environment.
• The project is set via PROJECT_ID (mapped to settings.GCP_PROJECT_ID).

Hazard Data Provider

The EarthEngineHazardDataProvider acts as a high-level provider that maps domain-specific hazard types (e.g., extreme_heat) to specific Earth Engine Image assets.

Integration Details

• Asset Locations: Hazard assets are stored as Earth Engine Images under projects/{PROJECT_ID}/assets/hazards/.
• Mapping: Asset IDs are dynamically constructed based on templates defined in backend/app/utils/hazard_layer_utils.py.
• Pre-scored Data: Most hazard layers are pre-scored on a scale of 1 to 5, allowing for consistent visualization across different hazard types.
• Visualization: The get_vis_params utility provides the appropriate color palette and min/max values (typically 1-5) for Earth Engine to generate tiles.