[Openspace] nb2listw

[Roger Bivand]

On Sat, 19 Apr 2008, Danlin Yu wrote:

> Mohamed:
>
> The error message is rather clear: there are islands in your data set that 
> don't (according to the way you define your neighborhood) have any neighbors. 
> In GeoDa, you can check which ones don't have neighbor by view the weight 
> characteristics.

Yes, the problem is that you have observations with no neighbours. You can 
set the zero.policy= argument to TRUE if you want to proceed, and you'll 
need the same argument set to TRUE in all analysis functions too. The 
print method for the neighbours list will tell you which the no-neighbour 
observations were.

Roger

>
> Hope this helps,
> Danlin
>
> mohamed ben ahmed wrote:
>>  Dear  Members,
>>  Can anyone tell me how to resolve this problem:
>>  for spatial data and using R, i created the contiguité list:
>>  staterook<-read.gal("rook.GAL"), it's ok
>>  but when i wanted to create the weight list by;
>>  staterook1<-nb2listw(statetook) , a message of error appears and say:
>>  Erreur dans nb2listw(staterook) : Empty neighbour sets found
>>  thnak you in advance
>>  Best Regards
>>  _______________________________________________
>>  Openspace mailing list
>>  Openspace at sal.uiuc.edu
>>  http://sal.uiuc.edu/mailman/listinfo/openspace
>> 
>
>

-- 
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