# Sentinel-1 SAR Download for Aura Fields

This folder contains scripts to download and preprocess Sentinel-1 SAR data for crop monitoring.

## Quick Start

### 1. Setup Environment
```powershell
# Navigate to the python_scripts directory
cd "c:\Users\timon\Resilience BV\4020 SCane ESA DEMO - Documenten\General\4020 SCDEMO Team\4020 TechnicalData\WP3\smartcane\python_scripts"

# Run setup script
python setup_sar_environment.py
```

### 2. Get SentinelHub Credentials
- Go to https://apps.sentinel-hub.com/
- Create account (free tier available)
- Get your Client ID and Client Secret
- The script will prompt for these when you first run it

### 3. Prepare Field Boundaries
- Make sure you have your field boundaries in GeoJSON format
- The script will look for files like:
  - `pivot.geojson` (current directory)
  - `pivot_20210625.geojson` (current directory)
  - `data/aura/field_boundaries/aura_fields.geojson`

### 4. Download SAR Data
```powershell
python download_s1_aura.py
```

## What the Script Does

1. **Downloads last 8 weeks** of Sentinel-1 data
2. **Downloads both VV and VH polarizations**
3. **Provides both linear and dB scales** for analysis
4. **Applies basic speckle filtering**
5. **Organizes by week** (week_XX_YYYY_BAND.tif format)

## Output Structure
```
data/aura/weekly_SAR_mosaic/
├── week_24_2025_VV.tif
├── week_24_2025_VH.tif  
├── week_24_2025_VV_dB.tif
├── week_24_2025_VH_dB.tif
├── week_24_2025_VV_dB_filtered.tif
├── week_24_2025_VH_dB_filtered.tif
└── ... (for each week)
```

## Files Created

- **`download_s1_aura.py`** - Main download script
- **`requirements_sar.txt`** - Python dependencies
- **`setup_sar_environment.py`** - Environment setup helper
- **`sar_download.log`** - Download log file

## Troubleshooting

### Common Issues:
1. **Import errors**: Run `python setup_sar_environment.py` first
2. **Credential errors**: Make sure SentinelHub credentials are correct
3. **No data found**: Check if field boundaries are loaded correctly
4. **Large downloads**: SAR data can be large, ensure good internet connection

### Check Log File:
```powershell
Get-Content sar_download.log -Tail 20
```

## Next Steps

After successful download:
1. Check the output files in `data/aura/weekly_SAR_mosaic/`
2. Move to R for analysis and visualization
3. Create SAR analysis scripts in R

## Notes

- **Free Tier Limits**: SentinelHub free tier has processing unit limits
- **Data Size**: Each weekly mosaic can be 50-200MB depending on area
- **Processing Time**: Downloads can take 5-15 minutes per week
- **Format**: All outputs are GeoTIFF with proper CRS information