[GRASSLIST:113] Census TIGER and COB

[Michael Ash]

Dear John,

You wrote:
> I have some questions for you.  From your shell script I
> am guessing that you are using census data possibly down
> to the "block" level.  I have recently been looking at
> the current code in Grass (v.in.tig.basic,
> v.apply.census, etc.)  Except that v.in.tig.basic still
> works, it looks old and not updated for census 2000
> data.
> 
> I was wondering what tools you used or if you had any
> scripts for working with the census 2000 data?  Or
> perhaps other advise or leads you could offer?

You are right that the scripts refer to Census data, but all
of the work on this particular project was done "by hand"
(as opposed to via TIGER) from STF3 files converting Census
block and block group data into sites on x,y coordinate
system specific to our project.  Messy and a nuisance
(although a good education for me on projections and data).

I just started working with v.in.tig.basic last week for a
different project and had no (apparent) difficulty applying
it to 2000 TIGER/Line data.  I cut the desired reaches from
the RT1 file using grep (grep 'A41', grep particular
streetnames, etc.), which was fairly crude, and I will
probably move to perl when I start seriously geocoding
addresses.  I'd be happy to share scripts as soon as I have
any.

As far as I could tell by testing the vector line maps in an
area that I know well and by overlaying Census boundary
files (imported with m.in.e00) and the TIGER lines,
v.in.tig.basic imported the 2000 TIGER data cleanly. I could
query with the mouse to get TLIDs, and query TLIDs with
d.vect.lines to highlight lines, etc., etc.

What do you have in mind by "not updated for census 2000
data"?  (I am very new to the TIGER data and would be
alarmed if v.in.tig.basic is doing something fundamentally
wrong with the 2000 data.)

As an aside, it would be a big improvement in v.in.tig.basic
if it could write .RT1 data to a database, e.g., PostGreSQL,
at the same time that it imports the RT1 and RT2 data into
GRASS. That would greatly facilitate geocoding addresses.

I'd be happy to correspond more about this question,
although I may be the source of more questions than of
answers.

Best regards,

Michael

Michael Ash, Assistant Professor 
  of Economics and Public Policy         
Department of Economics and CPPA
University of Massachusetts
Amherst, MA 01003        
Tel 413-545-6329 Fax 413-545-2921
Email mash at econs.umass.edu
http://people.umass.edu/maash