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Re: st: SPHDIST, creating pairs
From
TA Stat <[email protected]>
To
[email protected]
Subject
Re: st: SPHDIST, creating pairs
Date
Fri, 26 Feb 2010 17:15:28 +0700
starting from 2 separate files, public and private schools. sort by
District ID, then using joinby command and using unmatched and merge
option. it will run all pairwise combinations from master file
(publicschool) with using file (privateschool) and keep all those
variables from both files.
use "C:\publicschool.dta", clear
joinby DistrictID using "C:\privateschool.dta", unmatched(both) _merge(merge)
then you can use replace command to replace those missing data.
hope this help
tastat
On Fri, Feb 26, 2010 at 4:26 AM, Tomeka Davis <[email protected]> wrote:
> Hello -
>
> I am trying to calculate distance between two points using longitude and latitude data. I have come across 2 different Stata commands to do this - SPHDIST and VICENTY. I have not been able to install the VICENTY command. It appears from previous StataList posts that there might be problems associated with it and therefore it is temporarily unavailable (right?).
>
> Although I have longitude and latitude data, I am not sure how to create the pairs necessary to calculate distance with SPHDIST. I would like to calculate distance from a each public school in a district to all the other private schools in the same district. My data SHOULD look like this:
>
> District ID Public School ID Private School ID Public Longitude Public Latitude Private Latitude Private Longitude
> 1 A 1
> 1 A 2
> 1 B 1
> 1 B 2
> 1 B 3
> 1 B 4
> 2 C 1
> 2 C 2
> 2 C 3
> 2 D 1
> 2 D 2
>
> I initially had two separate files; one with public school data and one with private school data. I appended the public school file and tacked on the private school data.
>
>
> NOW the data looks something like this
>
> Distric ID School ID Public School Private School Latitude Longitude
> 1 A Y N
> 1 A Y N
> 1 B Y N
> 1 B Y N
> 1 B Y N
> 1 B Y N
> 2 C N Y
> 2 C N Y
> 2 C N Y
> 2 D N Y
> 2 D N Y
>
>
>
> But I want to pair each public school with each private school.
>
> So far, I have figured out how to produce a data set pairing ALL schools within each district; this would pair public schools within a district with other public schools in the same district (using a an FAQ page from 2005 written by Nick Cox titled "Expanding datasets to all possible pairs"). However, I don't want this. I only want to pair each public school with each private school in the same district.
>
>
> How do I accomplish this?
>
> I would appreciate any help anyone could offer. Also, any suggestions about the best distance command would be appreciated.
>
>
> Thank you.
>
>
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