True-Sun Shadow Plotter

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True-Sun Shadow Plotter

A precision solar-geometry tool that generates real shadow directions, sunrise arcs, and hour-line sundials for any location on Earth.

Uses true solar calculations (declination, equation of time, hour angle) to create RTK-grade plotted geometry you can load directly into SW Maps or Google Earth.

⭐ Features

• Real shadow mode — shows exactly where a pole’s shadow falls at any hour
• Sunrise Mode — plots the actual shadow direction at sunrise, including the full ~63° seasonal swing
• Season Pack — creates solstice & equinox arcs (Jun 21, Mar 20, Sep 22, Dec 21)
• Mowing Band — highlights the full-year shadow sweep between summer & winter
• Units toggle (m/ft)
• Hour-step resolution down to 5 minutes
• One-tap KML export for:
  • Hour lines
  • Seasonal arcs
  • Sunrise shadow lines
  • Shadow-tip points
  • Center marker
• 100% browser-based, no server needed

🏗 Great For

• RTK surveying / GIS
• Solar panel & building alignment
• Landscape & orchard design
• Artistic field mowing (sunrise arcs, seasonal bands)
• Educational demonstrations of Earth’s tilt and seasons
• Plotting accurate sundials of any size
• Verifying RTK accuracy with known geometries

📥 How to Use

1. Enter your latitude, longitude, and timezone
2. Choose Hour-line, Sunrise, or Both
3. Pick a date or turn on Season Pack
4. Tap Preview to visualize
5. Tap Calculate → Share KML
6. Open in Google Earth or SW Maps for field use

📐 What makes it unique?

Unlike normal sundial calculators, this tool shows:

• Real shadow lengths (not fixed radius)
• Seasonal movement due to Earth’s axial tilt
• Sunrise shadow swing across the horizon
• Full-year shadow envelopes you can mow or mark with stones
• RTK-friendly KML geometry tied to your exact coordinates