Thank you for your useful response. I will study it carefully. Best regards, Phil Smith
(Ted Harding) wrote: > On 06-Sep-07 18:42:32, Philip James Smith wrote: > >> Hi R-ers: >> >> I need to compute the distance between 2 street addresses in >> either km or miles. I do not care if the distance is a "shortest >> driving route" or if it is "as the crow flies." >> >> Does anybody know how to do this? Can it be done in R? I have >> thousands of addresses, so I think that Mapquest is out of the >> question! >> >> Please rely to: [EMAIL PROTECTED] >> >> Thank you! >> Phil Smith >> > > That's a somewhat ill-posed question! You will for a start > need a database of some kind, either of geographical locations > (coordinates) of street addresses, or of the metric of the > road network with capability to identify the street addresses > in the database. > > If it's just "as the crow flies", then it can be straightforwardly > computed in R, either by Pythogoras (when they are not too far > apart) or using a function which takes account of the shape of > the Earth, > > There are many R packages which have to do with mapping data. > Search for "map" through the list of R packages at > > http://finzi.psych.upenn.edu/R/library/maptools/html/00Index.html > > -- maptools in particular. Also look at (for instance) aspace. > > For "shortest driving route" then you need to find the shortest > distance through a network. You may find some hints in the > package optim -- but there must be some R experts out there > on this sort of thing! > > However, the primary need is for the database which gives > the distance information in one form or another. What were > you proposing to use for this? As far as I know, R has no > database relevant to street addresses! > > Best wishes, > Ted. > > -------------------------------------------------------------------- > E-Mail: (Ted Harding) <[EMAIL PROTECTED]> > Fax-to-email: +44 (0)870 094 0861 > Date: 06-Sep-07 Time: 23:17:57 > ------------------------------ XFMail ------------------------------ > > ______________________________________________ R-help@stat.math.ethz.ch mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
