OpenEuphoria

Re: [off topic] distance

• Posted by jiri babor <jbabor at PARADISE.NET.NZ> Dec 28, 2000
• 474 views

Kat,

Since no-one else has moved so far, try the following function. It's
pretty rough, but it should be reasonably accurate for distances up
several hundred kilometers. If you want your answer in miles, just
divide the returned value by 1.609.

jiri

--  earth.ex
--  jbabor at paradise.net.nz
--  00-12-28

constant R = 6371.02        -- mean earth radius in km
constant pi = 3.141593      -- close enough
constant d2r = pi/180       -- degrees-to-radians (~0.0174533)
constant c = d2r * R        -- ~111.1953 km per degree latitude

function distance(atom la1, atom lo1, atom la2, atom lo2)
    atom u,v

    u = (lo2-lo1) * (cos(d2r*la1) + cos(d2r*la2)) / 2
    v = la2-la1
    return c * sqrt(u*u + v*v)
end function

? distance(41.3, 174.7, 37.0, 174.7)    -- Wellington-Auckland
? distance(41.3, 174.7, 33.7, 151.3)    -- Wellington-Sydney

----- Original Message -----
From: "Kat" <gertie at PELL.NET>
To: <EUPHORIA at LISTSERV.MUOHIO.EDU>
Sent: Thursday, December 28, 2000 5:28 PM
Subject: [off topic] distance


> Hi all, off topic question... does anyone already have code for
determining
> Earth surface distance, given latitude and longitude points of two
locations?
>
> Kat
>