R help - Apr 2011 - Geographic distance between lat-long points in R?

Dear R, 


I have a bunch of geographic locations specified by lat-long coordinates.
What's an easy way to calculate geographic distance between any two points?
OR, perhaps there is a function for calculating a distance matrix for K sites?


Sincerely, 
Scott Chamberlain




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I found something here
http://www.biostat.umn.edu/~sudiptob/Software/distonearth.R

#The following program computes the distance on the surface of the earth
between two points point1 and point2. Both the points are of the form
(Longitude, Latitude)
  
geodetic.distance <- function(point1, point2)
{
R <- 6371
p1rad <- point1 * pi/180
p2rad <- point2 * pi/180
d <-
sin(p1rad[2])*sin(p2rad[2])+cos(p1rad[2])*cos(p2rad[2])*cos(abs(p1rad[1]-p2rad[1]))
d <- acos(d)
R*d
}

Dirk

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Hi Scott,
have a look at the 'earth.dist'-function in the package
'fossil'.

hth.

Am 11.04.2011 17:37, schrieb Scott Chamberlain:
> Dear R, 
> 
> 
> I have a bunch of geographic locations specified by lat-long coordinates.
What's an easy way to calculate geographic distance between any two points?
OR, perhaps there is a function for calculating a distance matrix for K sites?
> 
> 
> Sincerely, 
> Scott Chamberlain
> 
> 
> 
> 
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> 
> ______________________________________________
> R-help at r-project.org 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.
-- 
Eik Vettorazzi
Institut f?r Medizinische Biometrie und Epidemiologie
Universit?tsklinikum Hamburg-Eppendorf

Martinistr. 52
20246 Hamburg

T ++49/40/7410-58243
F ++49/40/7410-57790

Please allow me to present you the ultimate distance calculation algorithm by
Charles Karney, accurate to one nanometre:
http://geographiclib.sourceforge.net/cgi-bin/Geod

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