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| From | Austin Nichols <austinnichols@gmail.com> |
| To | statalist@hsphsun2.harvard.edu |
| Subject | Re: st: SPHDIST, creating pairs |
| Date | Thu, 25 Feb 2010 17:07:57 -0500 |
This was sent in plain text but seems in the archive to have gotten cut off after 3 lines, for some reason. On Thu, Feb 25, 2010 at 4:39 PM, Austin Nichols <austinnichols@gmail.com> wrote: > Tomeka Davis <soctmd@langate.gsu.edu> : > This works fine for me: > ssc inst vincenty > > From what Statalist post do you infer problems? > > Do you actually want to match all those pairs, or do you want to > compute some statistic based on the distances? The latter does not > require making a crossed file; see e.g. > http://www.stata.com/statalist/archive/2009-09/msg00493.html > > On Thu, Feb 25, 2010 at 4:26 PM, Tomeka Davis <soctmd@langate.gsu.edu> 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. >> >> > * * 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/