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From |
Austin Nichols <austinnichols@gmail.com> |

To |
statalist@hsphsun2.harvard.edu |

Subject |
Re: st: calculate pairwise distance between tracts |

Date |
Thu, 4 Nov 2010 17:34:26 -0400 |

sara borelli <saraborelli77@yahoo.it> : If you really want to cross the data, see -help cross-, but that may produce a really large dataset. You should consider looping over observations and computing the distance of each tract from tract i within the loop, computing what you need and saving only the relevant info. See also e.g. http://www.stata.com/statalist/archive/2009-07/msg00257.html FYI, -vincenty- is on SSC. On Thu, Nov 4, 2010 at 5:21 PM, sara borelli <saraborelli77@yahoo.it> wrote: > Dear statalister > I am trying to calcluate pariwise distance between census tracts whithin state. I have longitude and latitude for each tract and I know vincenty command calculate distance > However, I am having sme troubles to organize data in the appropriate way to apply the command > > suppose I have > tract > 1 > 2 > 3 > > if I put the data in the form > > tract_orgin tract_Dest long_orig long_dest lat_orig lat_dest > 1 1 > 1 2 > 1 3 > 2 1 > 2 2 > 2 3 > 3 1 > 3 2 > 3 3 > > if I organize the data in this way I can apply > vincety (lat_orig long_orig lat_dest long_dest) whihc gives me distance between any 2 tracts > > the problem is that I am having hard time to organize the data in that format given the large number of census tracts > > any suggestion on how to do this efficiently? > thanks > * * 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/

**Follow-Ups**:**Re: st: calculate pairwise distance between tracts***From:*sara borelli <saraborelli77@yahoo.it>

**References**:**st: calculate pairwise distance between tracts***From:*sara borelli <saraborelli77@yahoo.it>

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