[R-sig-Geo] GWR SDF

[Roger Bivand]

On Mon, 13 Nov 2006, Raphael Saldanha wrote:

> Help!
> 
> In the SDF results, what exactly means these fields:
> 
> sum_w
> X.Intercept
> V04
> V05
> X1
> X2
> X3

The spgwr package is not really intended to help people use GWR, which is
not generally accepted as a technique of analysis (because it forces
coefficients to co-vary), though it can be used for exploration. It is
rather a toolbox for examining the method. For this reason, not much
effort has been put into things like names. You would have to say what all 
the names are in this case:

names(res.adpt$SDF)

The v04, V05 look odd, but without seeing all the names, it is difficult 
to tell. The X1-X3 are probably three of the local standard errors. s_w is 
the sum of weights at that point, and X.Intercept is the local intercept 
estimate.

What happens when you run a regular regression? Do any of the coefficients 
disappear (any collinear variables)?

Roger

> 
> I'm using this code:
> 
> > x <- readShapePoly("domicilio_3136702.shp", IDvar = "ID_")
> > x.adapt.gauss <- gwr.sel(V03 ~ V06 + V07 + V08, data=x, adapt=TRUE)
> > res.adpt <- gwr(V03 ~ V06 + V07 + V08, data=x, adapt= x.adapt.gauss,
> hatmatrix = TRUE)
> 
> 

-- 
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