[GRASSLIST:3100] Re: Xtent Modelling (wieghted Thieseen)

Colin Nielsen nielsen at myrealbox.com
Mon Apr 5 20:13:58 EDT 2004

I'm an archaeologist trying to determine possible territories/influence around sites. I want to give certain sites a greater weight of influence than others (such as a capital city vs a small farm). It would be relatively easy to impliment from a programmers point of view. Instead of drawing the boundary at 50% between the sites put it at 70% or whatever based on the wieghting. I was just hoping someone had already done this. Yes/ no?


-----Original Message-----
From: Hamish <hamish_nospam at yahoo.com>
To: "Colin Nielsen" <nielsen at myrealbox.com>
Date: Mon, 5 Apr 2004 11:41:04 +1200
Subject: [GRASSLIST:3094] Re: Xtent Modelling (wieghted Thieseen)

> Does anyone know of a way to rank sites so that the theissen polygons
> are larger around higher ranked/weighted sites? I don't see any
> weighting/ranking option in the s.voronoi module. Any ideas?

Isn't that contrary to the point of Theissen (Voronoi) polygons? Namely
they are defined as areas where in all points are closer to a common
site than to any other site, and created by connecting the centroids of
Delaunay triangles?

I think it is better to assign a weight to each polygon (ie the same
weight as its associated site) and construct a weighted mean or whatever
from that using r.mapcalc rather than actually changing the shape of the


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