// compute the distance between places using the Haversine formula

distance = function( th1Deg, ph1Deg, th2Deg, ph2Deg )
    toRadians = pi / 180
    ph1 = toRadians * ( ph1Deg - ph2Deg )
    th1 = toRadians * th1Deg
    th2 = toRadians * th2Deg
    dz  = sin( th1 ) - sin( th2 )
    dx  = cos( ph1 ) * cos( th1 ) - cos( th2 )
    dy  = sin( ph1 ) * cos( th1 )
    return asin( sqrt( dx * dx + dy * dy + dz * dz ) / 2 ) * 2 * 6371
end function

d  = distance( 36.12, -86.67, 33.94, -118.4 )
km = round( d )
mi = round( d / 1.609344 )
print( "distance: " + km + " km (" + mi + " mi.)" )