writing shapefiles using write.pointShape

From: Roger Bivand <Roger.Bivand at nhh.no>
Sent: Mar 16, 2008 4:42 AM
To: modern82376 at mypacks.net
Cc: r-sig-geo at stat.math.ethz.ch
Subject: Re: [R-sig-Geo] writing shapefiles using write.pointShape

On Thu, 13 Mar 2008, modern82376 at mypacks.net wrote:

I'm also having issues with getting the gw.cov function to work for fit 
points. Here's an example, using the same files...

pcavars <- names(surveypts[,4:8])
pcavars

[1] "pca1" "PCA2" "PCA3" "PCA4" "PCA5"

surv.cov <- gw.cov(data = surveypts, vars = pcavars, fit.points = fitpix, bw = survey.bw)

Error in gw.cov(surveypts, test, fit.points = fitpix, bw = survey.bw) :
 unused argument(s) (fit.points = <S4 object of class "SpatialPixels">)

As far as I can tell, I'm using the same syntax as in the ggwr function. 
Thanks again. =)

?gw.cov will help. The first argument is x= not data=, and fit.points= 
should be fp=. So

surv.cov <- gw.cov(x=surveypts, vars=pcavars, fp=fitpix, bw=survey.bw)

ought to work. The functions are fairly different (no formula=), so 
assuming that the arguments have the same names suggests that actually 
reading the help pages might save time.

Please note that spgwr is only a proof of concept package and does not 
imply any affirmation of approaches using geographical weights. The 
approach may be helpful, but following Wheeler and Tiefelsdorf (2005), 
caution is recommended. Your use of PCAs may help alleviate the induced 
collinearity in GWR regression coefficients, but please always plot 
pairs() of the local coefficients!