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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: > > * http://www.stata.com/help.cgi?search > > * http://www.stata.com/support/statalist/faq > > * 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/> > > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ > > * > * For searches and help try: > * http://www.stata.com/help.cgi?search > * http://www.stata.com/support/statalist/faq > * http://www.ats.ucla.edu/stat/stata/ > * * For searches and help try: * http://www.stata.com/help.cgi?search * http://www.stata.com/support/statalist/faq * http://www.ats.ucla.edu/stat/stata/

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