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Re: st: data points within radius?


From   David Torres <torresd@umich.edu>
To   statalist@hsphsun2.harvard.edu
Subject   Re: st: data points within radius?
Date   Tue, 07 Jul 2009 09:58:00 -0400

Austin,

Thanks for the tip.  I figured there was a way to complete this
process in a loop, but as I'm not too familiar with the intricacies of
stata code (and don't possess a good text on it) I just waste a lot of
time trying different things based on other code I've seen.  At any
rate, allow me to give an example of the data I'm working with
(already nonmatch merged and abbreviated for simplicity).

input   gisjoin     longitude   latitude     sch_lon    sch_lat   unitid
G0600010400100   -124.5746   39.97379   -85.95683   31.80067   102368
G0600010400200   -124.5933   39.95392   -86.25552   31.30878   101107
G0600010400300   -124.5983   39.94619   -86.86419   33.10434   101709
G0600010400400   -124.6022   39.95378   -87.67984   34.73044   101736
G0600010400500   -124.6101   39.95397   -85.94818   32.92472   100760
G0600010400600   -124.6098    39.9473   -86.16864   32.38251   101958
G0600010400700   -124.6177   39.94698   -86.99479   33.36999   100919
G0600010400800   -124.6299   39.95023   -87.55314   33.09406   102067
G0600010400900   -124.6261   39.94432   -85.83498   31.29919   101143
G0600010401000   -124.617   39.93631   -85.68978   32.42277   102216
G0600010401100   -124.6081    39.9358   -87.01451   32.44433   101301
G0600010401200   -124.6017   39.93617   -86.34469   32.34993   102313
G0600010401300   -124.6105    39.9232   -86.31091   32.37661   102359
G0600010401400   -124.6178    39.9257   -86.79467   33.46106   102049
G0600010401500   -124.6257    39.9277    -87.0184   32.42337   101073
end

The first three columns represent information from the master data, while the remaining three columns represent information from the using data set. I'm supposing that additional variables can be excluded in this example since what I need is the total number of unitids--of the using data set--in a radius of, say, 50 miles of gisjoin--of the master data set.

Thanks,
Diego

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

David Diego Torres, MA(Sociology)
PhD Candidate in Sociology

2030D Population Studies Center
University of Michigan Institute for Social Research
Ann Arbor MI  48106-1248
Tel 734.763.4098
Fax 734.763.1428
torresd at umich dot edu

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