Issue #3: 🟡 Implement Data Processing & Harmonization Layer

[ZEZE1020]

Description

Create a unified data processing layer to harmonize data from multiple sources with different formats and units.

Tasks

Phase 1: Harmonization

• Create DataHarmonizer class
• Standardize units (µg/m³, ppb)
• Normalize timestamps to UTC
• Convert coordinates to WGS84
• Implement AQI calculation (EPA formula)

Phase 2: Spatial Matching

• Create SpatialMatcher class
• Match TEMPO pixels with ground stations
• Find the nearest station for the location
• Interpolate missing timestamps
• Handle time zone conversions

Phase 3: Quality Checks

• Validate data ranges
• Flag outliers
• Check data freshness
• Compute quality scores (0-100)

Phase 4: Unified API

• Create combined endpoint
• Return standardized format
• Include quality indicators
• Add confidence intervals

Files to Create

backend/src/data_processing/
├── harmonizer.py
├── spatial_matcher.py
├── quality_checker.py
├── aqi_calculator.py
└── time_aligner.py

New API Endpoints

GET /api/v1/data/unified?lat={lat}&lon={lon}
GET /api/v1/data/comparison?lat={lat}&lon={lon}
GET /api/v1/data/grid?bounds={bounds}&pollutant={pollutant}

Acceptance Criteria

• All data in consistent units
• Timestamps normalized
• AQI calculated correctly
• Spatial matching works
• Quality scores computed
• Unified endpoint functional
• Data validation is working

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