• cheeseburger@lemmy.ca
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      5 months ago

      10,152 Km between Atlanta and Tbilisi, and ChatGPT gave the pseudocode below as an explanation, which I didn’t double check before making this comment!

      
      # Coordinates for Atlanta, Georgia, USA
      atlanta_coords = (33.7490, -84.3880)
      
      # Coordinates for Tbilisi, Georgia (country)
      tbilisi_coords = (41.7151, 44.8271)
      
      # Calculate the straight line distance through the Earth
      geopy.distance.great_circle(atlanta_coords, tbilisi_coords).km```
      • Gobbel2000@programming.dev
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        5 months ago

        That’s wrong, it calculates the surface distance not the distance through the earth, while claiming otherwise. From the geopy.distance.great_circle documentation:

        Use spherical geometry to calculate the surface distance between points.

        This would be a correct calculation, using the formula for the chord length from here:

        from math import *
        
        # Coordinates for Atlanta, West Georgia
        atlanta_coords = (33.7490, -84.3880)
        # Coordinates for Tbilisi, Georgia
        tbilisi_coords = (41.7151, 44.8271)
        
        # Convert from degrees to radians
        phi = (radians(atlanta_coords[0]), radians(tbilisi_coords[0]))
        lambd = (radians(atlanta_coords[1]), radians(tbilisi_coords[1]))
        
        # Spherical law of cosines
        central_angle = acos(sin(phi[0]) * sin(phi[1]) + cos(phi[0]) * cos(phi[1]) * cos(lambd[1] - lambd[0]))
        chord_length = 2 * sin(central_angle/2)
        
        earth_radius = 6335.439 #km
        print(f"Tunnel length: {chord_length * earth_radius:.3f}km")
        

        A straight tunnel from Atlanta to Tbilisi would be 9060.898km long.