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Re: Fwd: st: spatial weighting matrix


From   "Susan Olivia" <olivia@primal.ucdavis.edu>
To   statalist@hsphsun2.harvard.edu
Subject   Re: Fwd: st: spatial weighting matrix
Date   Wed, 08 Apr 2009 12:22:08 -0700

Dear all,

To follow up on the spatial weighting matrix topic, does
anyone have any suggestion how to integrate sparse matrix
routines in STATA? 

Thanks,

Susan

----- Original Message Follows -----
From: Susan Olivia <susan.olivia@gmail.com>
To: Susan Olivia <olivia@primal.ucdavis.edu>
Subject: Fwd: st: spatial weighting matrix
Date: Wed, 8 Apr 2009 10:59:46 -0700

> ---------- Forwarded message ----------
> From: Nick Cox <n.j.cox@durham.ac.uk>
> Date: Wed, Apr 8, 2009 at 10:56 AM
> Subject: RE: st: spatial weighting matrix
> To: statalist@hsphsun2.harvard.edu
> 
> 
> I think that's all correct, but one extra detail may bite.
> For example, a common size of problem is all 3000 or so
> counties in the USA. For coding contiguities for that, you
> really need to have or to mimic sparse matrix routines.
> 
> Nick
> n.j.cox@durham.ac.uk
> 
> Kyle Hood
> 
> Thanks for the explanation of queen - I do recall that
> chess references are used, now; I guess I had forgotten
> since I have never based a weight
> 
> matrix on contiguity.
> 
> I am a little confused about what the asker wants from
> Stata, here.  He says he has addresses (points), but wants
> a weighting matrix that depends on contiguity, which only
> makes sense for areal data.  If these addresses contain
> the areas in question (for example, zip codes or states)
> then no geocoding is necessary -- one must simply extract
> the areas from the address data.  However, after that, the
> information concerning which areas are adjacent to others
> is needed.  I can't imagine that Stata can be used to
> obtain this information.  If the asker
> 
> has this information already, then it would of course be
> trivial to program the weighting matrix in Stata (using
> Mata or not).
> 
> If the addresses do not contain the areas in question (for
> example, the asker wishes to consider adjacent census
> tracts, but has street address data), then the address
> information will have to be geocoded.  The geocoded data
> must then be matched up with a map of census tracts based
> on location.  In addition, information on which census
> tracts were adjacent would be needed, and this presents
> the same problem as above.
> 
> Some of this can be done in Stata, but there are pieces
> that other software is better suited to deal with.
> 
> Nick Cox wrote:
> > The queen terminology in spatial analysis comes via
> chess. >
> > Imagine squares on a chessboard.
> >
> > A queen can enter a neighbouring square either across a
> > length of boundary (over a link or edge in a boundary
> > network) or diagonally (if two areas touch at a vertex
> or node in a boundary network). >
> > A rook or castle is limited to the first of those.
> >
> > In chess there are of course also other rules but they
> > do not enter here.
> >
> > Thus "queen" implies contiguity wide sense and "rook"
> strict sense. >
> > The terminology goes back at least as far as the work of
> > geographer Andrew Cliff and econometrician-statistician
> > Keith Ord in the late 1960s.
> >
> > In terms of the question, I implemented weighting
> > matrices via string variables [!!!] in -spautoc- on SSC
> in 1997, but I'd do it in Mata now,
> > but I don't have detailed advice, let alone code.
> >
> > Nick
> > n.j.cox@durham.ac.uk
> >
> > Kyle Hood
> >
> >
> > I'm not sure what "first-order queen contiguity" is, but
> > you will probably have to geocode address data (geocode:
> address->lat/lon), and I
> >
> > don't think you can do this in Stata (that is, unless
> > the breadth of Stata's capabilities is larger than I had
> realized, which is sometimes
> 
> > the case).  Try ArcGIS.  Once you have the geocoded data
> > , you can probably compute the weight matrix in Stata,
> if you want. >
> > max r wrote:
> >
> >
> >> I need to create a spatial weighting matrix
> (first-order queen >> contiguity) for a unbalanced panel
> dataset. The dataset has address >> information in it. Is
> there a way to do this in STATA? I am trying to >> test
> for neigborhood effects in behavior. Appreciate your
> thoughts. >>
> >
> > *
> > *   For searches and help try:
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> > *   http://www.ats.ucla.edu/stat/stata/
> >
> 
> 
> --
> Kyle Hood
> Department of Economics
> Yale University
> New Haven, CT
> website:
>
http://www.econ.yale.edu/~kkh25/<http://www.econ.yale.edu/%7Ekkh25/>
> 
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