[R-sig-Geo] "txt" to "listw"

[Zz]

I appreciate the instant answers from Dr. Bivand and Dr. Kawalerowicz.
Your R commands help me solve a tough problem.



Wishing everyone a relaxing weekend
Zz




On 3/23/12, Roger Bivand <Roger.Bivand at nhh.no> wrote:
> On Wed, 21 Mar 2012, anny peng wrote:
>
>> Dear R users,
>>
>> Thank Dr. Divand for creating spdep, and thank everyone for your
>> attention.
>>
>> I attach a 30*30 matrix, which consists of 0 and 1.  The matrix is  a
>> "txt" file.  I would like to change this matrix into a ".listw" file
>> so that I can estimate spatial auto-correlation.
>>
>> As a new user, I have difficulties in reading "txt" file and use the
>> function "mat2listw".
>>
>> Below are my errors.
>>
>>
>> data1= read.fwf("30_30.txt", widths=1)
>
> The problem was resolved off-list. The main issue was about reading the
> tab-separated file into a matrix for use in mat2listw():
>
> mat0 <- read.table("30_30.txt", header=FALSE, sep="\t", fill=TRUE)
>
> and converted into a matrix with:
>
> mat <- as.matrix(mat0)
> dim(mat)
>
> However, it has NAs, not 0, where there are no neighbours, so this must be
> repaired:
>
> summary(c(mat))
> mat[is.na(mat)] <- 0
> summary(c(mat))
>
> Reading the R Data Import/Export manual would have helped, together with
> the use of CSV as the spreadsheet output format - the fields here are not
> of fixed width, although they look like that; tabs are used as field
> separators, but fields with 1s in have a width of 2, while empty fields
> have a width of 1.
>
> Finally:
>
> lw <- mat2listw(mat, style="B")
> summary(lw)
>
> Roger
>
>>
>>
>> coords <- coordinates(data1)
>> col005 <- dnearneigh(points, 0, 1, attr(col.gal.nb, row.names = IDs))
>> summary(col005)
>> col005.w.mat <- nb2mat(col005, zero.policy=TRUE)
>> col005.w.b <- mat2listw(col005.w.mat)
>>
>> ......
>>
>>
>>
>> Best regard
>> Zz
>>
>
> --
> Roger Bivand
> Department of Economics, NHH Norwegian School of Economics,
> 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
>
>