If the counties already exist as a vector within Grass, then yes, lat/long
output is easy. But the counties have to be loaded into Grass beforehand;
once you have a Grass vector of either a) points of US counties, or, very
similar, b) areas of counties with centroids, then distance calculations are
straightforward. There is an option within the program v.to.db to upload the
lengths of vectors into an attribute table; If you could get lines between
respondent and clinic digitized automagically, then v.to.db would figure out
the distances for you.
I'm not sure if there's a way to connect two vector points from two
different maps with a newly digitized line in a third vector - maybe someone
else could comment on this?
--
Eric Patton
epatton@nrcan.gc.ca
-----Original Message-----
From: owner-GRASSLIST@baylor.edu [mailto:owner-GRASSLIST@baylor.edu] On
Behalf Of Scott Cunningham
Sent: Thursday, March 16, 2006 10:52 AM
To: GRASSLIST@baylor.edu
Subject: [GRASSLIST:172] calculating distance II
Also, is it straightforward to calculate the longitude/latitude of counties
using GRASS?