In an E-mail message, Eric Kostello wrote:
> 
> 
> The problem is that there is only one CFCC per TIGER line, and
> precedence is given to tranportation classifications. You will
> need to examine the ZIP codes on both sides of each line to see
> if they are different. If they are, that is a boundary.
> 
> Eric Kostello
> kostello@carson.math.ucla.edu
> 
> Oliver Weatherbee writes:
> > 
> > I am having trouble extracting zipcode boundaries from the tiger census
> > line files.  I extract the files matching the cfcc code F50 which is supposed
> > to correspond to the zip code boundaries but I get a total of 0 lines read
> > out.  I don't think its a scripting/software problem because it works for
> > other cfcc codes (F10, F73, etc.).
> > 
> > 	Oliver Weatherbee
> > 	oliver@earthview.cms.udel.edu
> 

I've come across a similar experience recently in Illinois.
I tried extracting zip code boundaries for Cook county, Illinois (Chicago) 
by CFCC F50 but came up with nothing.  I then tried extracting zip code
boundaries through comparison of left and right code numbers ( a la extracting
census tracts) but got only a few boundary lines and a bunch of discontinuous
line segments.  I used the following awk script to do this:

awk 'substr($0,107,5)!=substr($0,112,5)'

At this point I think the problem may be that zip code boundary info is only
available where address ranges occur. Although I thought this was only a 
problem in rural areas, it may also occur in urban areas as well.  I've been
using 1990 Tiger/Line Files but I know the 1992 files were supposed to have 
a lot of added information.  I put a call into the Census Bureau today and
expect to hear back on Monday.  Will keep you posted.

-- 
-------------------------

Paul Loechl					p-loechl@cecer.army.mil
USA CERL					(217)352-6511x668

