[Openspace] dissolve and contiguity

[Kevin Drakulich]

I know a similar question has been posted to this list before by Mike
Sobczak.  I believe there was no answer to that, but I'm hoping someone may
have one now.

Like Mike, I began with a Tiger shapefile, and used "geoprocessing>dissolve"
in ArcMap 8.2 to aggregate smaller polygons into bigger ones.  For me, the
move was from census tracts to "neighborhoods" (collections of census
tracts) within a city.

Also like Mike, when I created a contiguity-based weight file in GeoDA,
there are lots of mistakes in the file.  For some neighborhoods there are no
neighbors (which is clearly not the case), and for others, the neighbors
listed are clearly wrong (if you look into the .GAL file).

None of these problems exist if you bring in the original TIGER files of
census tracts pre-dissolved.

Has anyone else seen this problem or know what might be causing it?

Thanks much,
Kevin

Kevin M. Drakulich
University of Washington, Seattle