[R-sig-Geo] SpatialFiltering in spdep: How to create an 'nb' object from an imported spatial weights matrix

[Timo Mitze]

Dear Roger,

it works now, many Thanks!

Timo 

-----Ursprüngliche Nachricht-----
Von: Roger Bivand [mailto:Roger.Bivand at nhh.no] 
Gesendet: Sonntag, 15. Februar 2009 23:00
An: Timo Mitze
Cc: r-sig-geo at stat.math.ethz.ch
Betreff: Re: AW: [R-sig-Geo] SpatialFiltering in spdep: How to create an 'nb' object from an imported spatial weights matrix

On Sun, 15 Feb 2009, Timo Mitze wrote:

> Dear Roger and List,
>
> thanks for your advice. I tried it with the code as (as well as some related with different style parameter etc.):
>
> ********************************
> x <- mat2listw(mat)
> lw <- nb2listw(x$neighbours, style="B", zero.policy=TRUE) migfilt <- 
> SpatialFiltering(lnmr_i ~ 1, data=migration_spatial, nb=lw, style="B", 
> ExactEV=TRUE, zero.policy=TRUE)
> ********************************
>
> ... but unfortunately (always) got the following error message:
>
> ********************************
> Fehler in card(neighbours) :
>  INTEGER() can only be applied to a 'integer', not a 'character'
> ********************************
>
> Can it be the problem the the nb object is still missing, since I try 
> to directly create a listw object?

x$neighbours is the nb object, just use that.

Roger

>
> According to Yongwan Chun (one of the author of Spatial Filtering), 
> the routines needs an nb and NOT(!!!) a listw object. Can I generate 
> such an nb object from my binary 240x240 matrix?
>
> Greetings,
>
> Timo
>
>
> -----Ursprüngliche Nachricht-----
> Von: Roger Bivand [mailto:Roger.Bivand at nhh.no]
> Gesendet: Sonntag, 15. Februar 2009 13:31
> An: Timo Mitze
> Cc: r-sig-geo at stat.math.ethz.ch
> Betreff: Re: [R-sig-Geo] SpatialFiltering in spdep: How to create an 
> 'nb' object from an imported spatial weights matrix
>
> On Sat, 14 Feb 2009, Timo Mitze wrote:
>
>> Dear List,
>>
>> I have a complete (distance/border based binary) spatial weights 
>> matrix from Stata (e.g. as a txt-file).
>
> Try using read.dta() in foreign of the exported Stata matrix. This reads a data.frame, which you coerce to an R matrix with as.matrix().
>
>> I want to apply spatial filtering in
>> spdep, however the routine needs an "nb" object. Is there any way to 
>> extract the information from my matrix automatically (something like 
>> mat2nb ???) or do I have to edit the "nb" object by hand? (e.g. in 
>> terms of creating a GAL file by any text editor and then use 
>> "read.gal" option
>> - this strategy would mean a lot of work since I have a 240 x 240 
>> matrix). I'd be happy about any help.
>
> Next use mat2listw() in spdep to convert to a listw object, finally using:
>
> x <- mat2listw(mat)
> lw <- nb2listw(x$neighbours, glist=x$weights, style="?")
>
> where ? is your choice of style. mat2listw() just does the 
> convsersion, assigning a style of "M", which may not be recognised by 
> model fitting functions. Drop the glist= argument if the weights are 
> without importance
> - as I understand they are from your description of them as binary.
>
> Hope this helps,
>
> Roger
>
>>
>> Best wishes,
>>
>> Timo
>>
>> P.S.: I have tried it with a spatial weights matrix in spdep 
>> (mat2listw), but it does not work - see my code below:
>>
>> ****************************************************
>>
>> #### Code for Griffith Eigenvector Filtering ###
>>
>>
>>
>> library(spdep)
>>
>>
>>
>> migration_spatial <-
>> read.table("C:/migration_laptop/spdep_migration.txt", header=TRUE, 
>> sep="\t", na.strings="NA", dec=".", strip.white=TRUE)
>>
>>
>>
>> summary(migration_spatial)
>>
>>
>>
>> mat = matrix(0, 240, 240)
>>
>>
>>
>> mat[row(mat) >= col(mat)] <-
>> scan("C:/migration_laptop/spdep_Wmat_Chun_border.txt")
>>
>>
>>
>> # not sure if the following is needed :
>>
>>
>>
>> mat <- mat + t(mat)
>>
>>
>>
>> list(mat)
>>
>>
>>
>> migmat.listw <- mat2listw(mat)
>>
>>
>>
>> migmat.listw
>>
>>
>>
>> migfilt <- SpatialFiltering(lnmr_i ~ lnmr_i_lag1 + ldwager_ij_lag1 +
>> ldur_ij_lag1 + ldyrl_ij_fd_lag1 + ldq_ij_lag1 + ldpland_ij_lag1 + 
>> ldhc6_ij_lag1, data=migration_spatial, nb=migmat.listw, style="W", 
>> ExactEV=TRUE, zero.policy=TRUE)
>>
>>
>>
>> ****************************************************
>>
>>
>>
>>
>>
>>
>>
>>
>> 	[[alternative HTML version deleted]]
>>
>> _______________________________________________
>> R-sig-Geo mailing list
>> R-sig-Geo at stat.math.ethz.ch
>> https://stat.ethz.ch/mailman/listinfo/r-sig-geo
>>
>
> --
> 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
>
>
>
>
>

--
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