On Wed, 26 Nov 2003 [EMAIL PROTECTED] wrote:
> Hi,
> Has anyone got any R code (or are there any packages) that calculates
> the great circle distance between two geographical (lat, lon) positions?
>
Yes, there is R code in fields, function rdist.earth() taking vectors as
arguments for one solution, alternatively there is a C function in spdep:
void gcdist(double *lon1, double *lon2, double *lat1, double *lat2,
double *dist)
which needs to be put in a loop, but is specifically WGS84, and is based
on the implementation at:
http://home.att.net/~srschmitt/greatcircle.html
There may be other code too.
Roger
>
> Cheers
>
> Toby Patterson
> Pelagic Ecosystems Research Group
> CSIRO Marine Research
> Email: [EMAIL PROTECTED]
>
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--
Roger Bivand
Economic Geography Section, Department of Economics, Norwegian School of
Economics and Business Administration, Breiviksveien 40, N-5045 Bergen,
Norway. voice: +47 55 95 93 55; fax +47 55 95 93 93
e-mail: [EMAIL PROTECTED]
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