[R-sig-Geo] All zero link when reading a modified shapefile into R

[Danlin Yu]

Hi all-

When I read a shapefile using read.shape into R, and used Map2poly -> poly2nb to create my neighbor list, the summary of the newly created neighbor list indicates that all the regions have zero link.

The shapefile is a modified census tract shapefile of New Jersey: a few tracts that have no useful attributal information were deleted from the map (hence left some holes) in ArcGIS （Start Edit -> select -> delete).

The original shapefile (with all the tracts) was read fine and create the correct neighbor list. But when using this modified one, I got all zero link. The same happened when I used GeoDa. Is this because of the holes created in the shapefile by deleting some polygons? If so, how can I make it work? If not, can anyone please direct me to the right solution?

Many thanks.

Best,
Danlin

___________________________________________
Danlin Yu, Ph.D.
Assistant Professor
Department of Earth & Environmental Studies
Montclair State University
Montclair, NJ, 07043
Tel: 973-655-4313
Fax: 973-655-4072
email: yud at mail.montclair.edu