Haversine Distance

• 
• $d=2r\times arcsin(\sqrt{si{n}^2(\frac{{\phi }_2-{\phi }_1}{2})+cos({\phi }_1)cos({\phi }_2)si{n}^2(\frac{{\lambda }_2-{\lambda }_1}{2}))}$
• Haversine distance is the distance between two points on a sphere given their longitudes and latitudes
• The main difference is that no straight line is possible since the assumption here is that the two points are on a sphere.
• ssumed the points lie on a sphere
• As you might have expected, Haversine distance is often used in navigation
• calculate the distance between two countries when flying between them
• Note that it is much less suited if the distances by themselves are already not that large. The curvature will not have that large of an impact.