[GRASS-user] distance from extent to origin cost surfaces

[Jason Jorgenson]

---------- Forwarded message ----------
From: Jason Jorgenson <jjorgenson at gmail.com>
Date: Sun, Mar 30, 2008 at 10:48 AM
Subject: Re: [GRASS-user] distance from extent to origin cost surfaces
To: dylan.beaudette at gmail.com


Hi Dylan.  Ok, so maybe some background...  I use r.walk to create a
 cost surface using an archaeological site as the origin.  I determine
 through diet analysis how much food the ancient settlement would have
 required, and from that how much land they needed.  I then identify
 that area of suitable land surrounding the site by starting at the
 origin of the r.walk cost surface and moving outwards until enough
 land is contained.  lets say the cost surface's range is 0-72000 and
 the amount of land is contained at an extent of 36000 on the cost
 surface.  I want to know what the actual distance range that people
 had to travel to reach the outermomst extent of their catchment.  The
 extent is equal all around obviously, at 36000 seconds or 5 hours, but
 it would be nice to know the min/max distance as well.  Not necessary
 to know path routes or anything.  Simple distance is what I am after.
  Hope this makes more sense now.

 Kindest regards

 Jason



 On Sun, Mar 30, 2008 at 1:11 AM, Dylan Beaudette
 <dylan.beaudette at gmail.com> wrote:
 > On Saturday 29 March 2008, Jason Jorgenson wrote:
 >  > Hi everyone.  I am trying to determine the minimum and maximum
 >  > distance from the outermost extents of a cost surface (which I
 >  > genereated with r.walk) back to the origin.  Is there a way to do
 >  > this?
 >  >
 >  > Jason
 >
 >  can you elaborate?
 >
 >  usually r.drain is used in conjunction with r.walk / r.cost to find
 >  the "least-cost" path. Not sure how you would find the "most-cost" (?) path.
 >
 >  Cheers,
 >
 >  Dylan
 >
 >  --
 >  Dylan Beaudette
 >  Soil Resource Laboratory
 >  http://casoilresource.lawr.ucdavis.edu/
 >  University of California at Davis
 >  530.754.7341
 >





--
 Jason Jorgenson
 Post Grad Research Student
 University of Liverpool

 "To mess up a Linux box, you need to work at it; to mess up your
 Windows box, you just need to work on it"



-- 
Jason Jorgenson
Post Grad Research Student
University of Liverpool

"To mess up a Linux box, you need to work at it; to mess up your
Windows box, you just need to work on it"