local main = {}
function main.HaversineDistance(frame)
local lat1 = frame.args["lat1"]
local lon1 = frame.args["lon1"]
local lat2 = frame.args["lat2"]
local lon2 = frame.args["lon2"]
local radius = 6371 -- km
local dlat = math.rad(lat2-lat1)
local dlon = math.rad(lon2-lon1)
local a = math.sin(dlat/2) * math.sin(dlat/2) + math.cos(math.rad(lat1)) * math.cos(math.rad(lat2)) * math.sin(dlon/2) * math.sin(dlon/2)
local c = 2 * math.atan2(math.sqrt(a), math.sqrt(1-a))
return radius * c
end
return main
