Algorithm for Latitude-Long

GRASS GRASS user
1

Date: Tue, 23 Mar 1993 10:28:42 -0600
From: "Jacinda M. Barbehenn" <mountz@gis.uiuc.edu>
Message-Id: <199303231628.AA08469@murphy.gis.uiuc.edu>
Sender: lists-owner@max.cecer.army.mil
Reply-To: grassu-list@max.cecer.army.mil
To: grassu-list@max.cecer.army.mil
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
USACERL/UI GISLAB
mountz@gis.uiuc.edu

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 charon.er.usgs.gov (128.128.40.24).

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