Considering "boundary effect" in spdep or spgwr

On Thu, 28 Sep 2006, Hisaji ONO wrote:

Hello.

 In some "geo-spatial analysis" text books &

articles,

"boundary effect" was referred.

 For spatial weight matrix and its related

statistical

methods, this issue is very important, I think.

 For this issue, I've looked for this in "spdep"

and

"spgwr" in their "manual" pdf files, but no luck.

 Current version of these packages consider

"boundary

effect"? 

Yes, you are right that boundary (or edge) effects
can be important. They 
concern the extent to which inferences may change if
we change the edges 
of the study area, and/or the configuration effect
that occurs when some 
observations are fully surrounded (in the centre of
the study area) and 
others are on the edge. 

There is an indirect reference to this in the
joincount.test() example in
spdep - it uses different settings of the spatial
weights style= argument
to show how weights configuration can change
inference. So in spdep, the
only treatment is through the style= argument.

In spgwr, fitting adaptive bandwidths seems to be
one way of preventing
observations far from their neighbours being
impacted by a single global
distance bandwidth. The GWR book doesn't have edge
effects in its index.

Best wishes,

Roger

 Regards.

-- 
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.Bivand at nhh.no