SmartCane/r_app/experiments/interactive_sar_visualization/README_SAR.md
2025-09-05 15:23:41 +02:00

2.6 KiB

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

# 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

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:

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