---------- Forwarded message ---------- From: Jason Jorgenson <[EMAIL PROTECTED]> Date: Sun, Mar 30, 2008 at 10:48 AM Subject: Re: [GRASS-user] distance from extent to origin cost surfaces To: [EMAIL PROTECTED]
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 <[EMAIL PROTECTED]> 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" _______________________________________________ grass-user mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/grass-user
