On Mon, 1 Feb 2010, Servet Ahmet Cizmeli wrote:
Hello all,
I am about to perform a GWR analysis using measurements collected at sea
onboard a ship. Some of the stations are located at opposite sides of an
island or within adjacent bays... Measuring bird's flight distances between
the stations do not make sense at all those cases.
Is there any way to presently instruct the R's implementation of GWR that
the distances are to be measured along sea-ways? This would probably
necessitate the concurrent input of a land mask (or polygon).
As I presume the answer of the above question is NO (no mention of it
anywhere in the GWR documentation), I would like to know how difficult
would it be to add that functionality for a r-novice like me.
Look at the fish swims thread on this list recently:
https://stat.ethz.ch/pipermail/r-sig-geo/2010-January/007472.html
You'll see that several participants suggested using MDS to convert the
non-Euclidic distance matrix to a 2-column coordinate matrix
"representing" the relative position of the observations. You could use
those with GWR, I think. It wouldn't be exact, but at least closer to your
reality than bird flies.
Roger
thanks
Servet
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Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Helleveien 30, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 95 43
e-mail: roger.biv...@nhh.no
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