Hi,

The GWmodel_1.2-1 and GWmodel_1.2-3 are in two different versions. Actually, we updated the package twice from 1.2-1 to 1.2-3. Especially, the default kernel function is changed from "gaussian" to "bisquare". There is a note when you load the package V1.2-3. That's why the results will be different if you don't change the kernel function setting. Hope this clarify your doubts. 

Cheers,
Binbin



Dr Binbin Lu
Lecturer in School of Remote Sensing and Information Engineering
Wuhan University
binbinlu@whu.edu.cn
 
From: bhartendupandey
Date: 2014-07-16 03:07
To: r-sig-geo
Subject: [R-sig-Geo] GWmodel package results
Dear list, 
 
I am experimenting with the GWmodel package and I just ran an example code
(with LondonHP data) given in the reference manual for gwr.generalised()
function. Incidently, I ran it in two different computers installed with
different versions of the package. I noted differences between the results
(for both poisson and binomial models) from the two versions:
 
1. GWmodel_1.2-1
2. GWmodel_1.2-3 
 
Essentially, I noted that the bandwidth estimated using bw.ggwr() function
from the two versions were different, which is ultimately causing the GWR
model results to vary. Now I wonder what is causing the differences in
bandwidth estimates and more importantly, which version of the package is
reliable? 
 
I ran the following code:
 
data(LondonHP)
DM<-gw.dist(dp.locat=coordinates(londonhp))
bw.f1 <- bw.ggwr(BATH2~FLOORSZ,data=londonhp, dMat=DM)
res.poisson<-gwr.generalised(BATH2~FLOORSZ, bw=bw.f1,data=londonhp, dMat=DM)
bw.f2 <- bw.ggwr(BATH2~FLOORSZ,data=londonhp, dMat=DM,family ="binomial")
res.binomial<-gwr.generalised(BATH2~FLOORSZ, bw=bw.f2,data=londonhp,
dMat=DM,
family ="binomial")
Here is the sessionInfo() from the two computers: 
 
Computer 1: 
> sessionInfo()
R version 3.0.1 (2013-05-16)
Platform: x86_64-w64-mingw32/x64 (64-bit)
 
locale:
[1] LC_COLLATE=English_United States.1252 
[2] LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    
 
attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     
 
other attached packages:
[1] GWmodel_1.2-3     robustbase_0.91-1 maptools_0.8-30   sp_1.0-15        
 
loaded via a namespace (and not attached):
[1] DEoptimR_1.0-1  foreign_0.8-53  grid_3.0.1      lattice_0.20-15
[5] tools_3.0.1    
 
Computer 2: 
> sessionInfo()
R version 3.0.0 (2013-04-03)
Platform: x86_64-w64-mingw32/x64 (64-bit)
 
locale:
[1] LC_COLLATE=English_United States.1252 
[2] LC_CTYPE=English_United States.1252   
[3] LC_MONETARY=English_United States.1252
[4] LC_NUMERIC=C                          
[5] LC_TIME=English_United States.1252    
 
attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     
 
other attached packages:
[1] raster_2.1-16     lattice_0.20-15   GWmodel_1.2-1     robustbase_0.9-10
[5] maptools_0.8-26   sp_1.0-11        
 
loaded via a namespace (and not attached):
[1] foreign_0.8-53 grid_3.0.0     tools_3.0.0         
 
loaded via a namespace (and not attached):
[1] DEoptimR_1.0-1  foreign_0.8-53  grid_3.0.1      lattice_0.20-15
tools_3.0.1 
 
Many thanks for any help and your time.
 
Best regards,
Bhartendu
 
 
 
 
 
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