[R] nlme: spatial autocorrelation on a sphere

[Dan Bebber]

Please be assured, I really did "RTFM" (i.e. Pinheiro & Bates) as well as all the online sources, and have accessed the codes of the corStruct functions, but they do not reveal how the "metric" argument is used. Therefore, I can't reprogram to include "haversine" distance, as seen in the ramps package.

Smith et al. (2008) write "The spatial correlation structures in nlme are not directly used because they do not allow great circle distance, which is very commonly needed for spatial data" so there may be a case for adding this functionality to nlme.

If anyone knows a way in to the relevant code, please let me know.

Thanks
Dan

Reference
Smith BJ, Yan J & Cowles MK 2008. Unified Geostatistical Modeling for Data Fusion and Spatial Heteroskedasticity with R Package ramps. Journal of Statistical Software 25(10)


________________________________________
From: David Winsemius [dwinsemius at comcast.net]
Sent: 01 October 2012 17:32
To: Spencer Graves
Cc: Dan Bebber; r-help at r-project.org
Subject: Re: [R] nlme: spatial autocorrelation on a sphere

On Oct 1, 2012, at 8:34 AM, Spencer Graves wrote:

> On 10/1/2012 12:38 AM, David Winsemius wrote:
>> <snip>
>
>> LMCTVTFY: http://cran.r-project.org/web/views/Spatial.html
>>
>
>
>      What's LMCTVIFY?

Please accept my apologies for attempting to be cute and I also apologize to Mr Bebber for reading his request far too quickly. I was trying to use (C)RAN (T)ask (V)iews as a verb.

>      LMGTFY for LMCTVIY produced only LMGTFY, at least for me. There's space for it on Wikipedia ("RTFM") after LMGTFY (which I found using LMGTFY Wikipedia).

I don't think it warrants being enshrined. I might also  have written:  require(sos); findFn("metric spherical latitude longitude")  might produce. In this instance that approach found the ramps::corRSpher function, which has a "haversine" metric, much  more quickly than did my subsequent efforts with RSeek, which I conducted after I realized that Bebber had already made a good faith effort at identifying resources.

--


David Winsemius, MD
Alameda, CA, USA