Dear David,

Thanks a lot for your kind reply.

Unfortunately, distm() can not give me what I want. distm(), output the
distance matrix (but not in dist class).

Fortunately, I just realized that as.dist() from base R can convert matrix
to dist class.

Thanks again.

Best
Jian-Feng,

2011/11/8 David L Carlson <dcarlson@tamu.edu>

> Look at distm() in package geosphere.
>
> ----------------------------------------------
> David L Carlson
> Associate Professor of Anthropology
> Texas A&M University
> College Station, TX 77843-4352
>
>
> -----Original Message-----
> From: r-help-bounces@r-project.org [mailto:r-help-bounces@r-project.org]
> On
> Behalf Of Mao Jianfeng
> Sent: Tuesday, November 08, 2011 8:22 AM
> To: r-help@r-project.org
> Cc: bossa.package@gmail.com
> Subject: [R] from points in Lon/Lat to physical distance in dist class
>
> Dear R-listers,
>
> Here, I would like to hearing helps from you.
>
> I have GPS data (multiple points in the geographic scale) in
> longitude/latitude. I intend to calculate
> distance (in kilometer) among such points and output the distance matrix in
> dist class.
>
> I have gotten some progress, but I still can not get final goal. Could
> please give me any directions/advice?
>
> This email cc. to Mr. Pierre, the author of BoSSA package.
>
> Thanks a lot in advance.
>
> Best wishes,
>
> Jian-Feng, Mao
>
> #########################################
> What I have gotten are
> (1) distance among GPS points could be calculated by distGPS() function in
> BoSSA package. But, it can
> not output the distance in dist class. And, I do not know how to convert
> such distance matrix to dist class.
>
> (2) dist() function in base R can calculate distance among units and export
> it in dist class. But, it could not
> be used to work on points in lon/lat.
>
> (3) some dummy codes
> # (3.1) generate dummy points in lon/lat (in degree)
> points <- data.frame(lon=seq(95, 105),lat=seq(35, 45))
>
> # (3.2) calculate distance between points using distGPS()
>
> library(BoSSA)
>
> Geodist<-distGPS(points)
>
> str(Geodist)
> class(Geodist)
>
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>
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> PLEASE do read the posting guide
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> and provide commented, minimal, self-contained, reproducible code.
>
>


-- 
Jian-Feng, Mao

Post doc
Dept. of Molecular Biology
Max Planck Institute for Developmental Biology
Spemannstrasse 37-39
72076 Tuebingen
Germany
Blog: http://maojf.blogspot.com/

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