Algorithm for Latitude-Long

Gerald I. Evenden gie at
Tue Mar 23 13:23:27 EST 1993

> Date: Tue, 23 Mar 1993 10:28:42 -0600
> From: "Jacinda M. Barbehenn" <mountz at>
> Message-Id: <199303231628.AA08469 at>
> Sender: lists-owner at
> Reply-To: grassu-list at
> To: grassu-list at
> Subject: Algorithm for Latitude-Long
> I have a data set of the midpoints of counties based on latitude and
> longitude coordinates.  With this data set I want to create a matrix that
> lists the distances between counties.  However, to use latitude and longitude
> data, I need an algorithm that will correct for the longitude distances.
> Does anyone know of an algorithm that can do this?
> -jacinda barbehenn
>  mountz at

There is program within the PROJ.4 distribution called "geod" which
will compute the distances you want from pairs of geographic coordinates.
It was also available in rel3 proj distribution.  Documentation is in
the man file geod.1 in the distribution.

You can get PROJ.4 from ftp anon on (

Gerald (Jerry) I. Evenden   Internet: gie at
voice: (508)563-6766          Postal: P.O. Box 1027
  fax: (508)457-2310                  N.Falmouth, MA 02556-1027

More information about the grass-user mailing list