Please consider sun angle restrictions for TrueView flight planning based on photogrammetry best practices:
✅ Recommended Sun Angle for Photogrammetry
- General Rule: Photos should be captured when the sun angle is greater than 30° above the horizon for optimal illumination and minimal shadow distortion.
- Digital Photogrammetry Tolerance: You can go as low as 20° above the horizon, but expect more shadows and potential color inconsistencies.
✅ Why Sun Angle Matters
- Low Sun Angles (early morning or late afternoon):
- Increase long shadows, which can distort orthomosaics.
- Reduce overall brightness, making RGB colorization less accurate.
- High Sun Angles (near solar noon):
- Provide uniform lighting and minimize shadow artifacts.
- Improve radiometric consistency for photogrammetry and LiDAR colorization.
✅ Flight Planning Recommendations
- Plan Flights Within ±3 Hours of Solar Noon during winter months to maximize solar radiation and image quality.
- Use a Sun Angle Calculator (e.g., PlanetCalc or DQYDJ) to determine the best time for your latitude and date.
- Avoid flying when sun elevation is below 15°, as imagery will likely be too dark and shadow-heavy for reliable photogrammetry.
✅ Additional Considerations
- Atmospheric Conditions: Fog, haze, and cloud cover can further reduce effective illumination.
- Terrain and Structures: Tall buildings or rugged terrain amplify shadow issues at low sun angles.
- Winter Constraints: In winter, daylight hours are shorter, so scheduling flights near midday is critical.
