Summary

Two points have line of sight if light can travel from one to the other unobstructed with sufficent contrast for visibilty under clear atmospheric conditions. Many physical phenomenon are modelled including Earth's curvature, local topograpghy, atmospheric refraction, atmospheric scattering, and partial irradiation. Lines of sight are only consdered between summits with at least 300 m of prominence. This map shows 1111 ground-to-ground lines of sight that are over 300 km long. It is limited to lines of sight that are the longest for both summits involved.

Links

• Method
• Github
• CSV of lines of sight shown on map
• CSV of all lines of sight over 300 km long

Data Sources

1. Mountains by Prominence

Andrew Kirmse and Jonathan de Ferranti found all 11,866,713 summits on Earth with over 100 ft (~30 m) of prominence. Prominence is the minimum vertical distance one must descend to reach a higher point. This dataset is used to identify summits beyond the prominence threshold of 300 m.

2. Open-Meteo's Elevation API

Open-Meteo offers an elevation API that can be used to find the elevation of any point on Earth. This API is used to find the elevation of points between summits that could obstruct line of sight.

3. Beyond Horizons

Beyond Horizons has catalogued many of the longest lines of sight to ever be captured by photograph. These confirmed lines of sight are used to calibrate the way light bending is modelled from atmospheric refraction.