https://github.com/cran/gss
Tip revision: 9f0152d0fb61ff50420926206dd516f6589e7a23 authored by Chong Gu on 08 August 1977, 00:00:00 UTC
version 0.8-3
version 0.8-3
Tip revision: 9f0152d
LakeAcid.Rd
\name{LakeAcidity}
\alias{LakeAcidity}
\title{Water Acidity in Lakes}
\description{
Data extracted from the Eastern Lake Survey of 1984 conducted by the
United States Environmental Protection Agency, concerning 112 lakes
in the Blue Ridge.
}
\usage{data(LakeAcidity)}
\format{
A list containing 112 observations on the following variables.
\tabular{ll}{
\code{ph} \tab Surface ph.\cr
\code{cal} \tab Calcium concentration.\cr
\code{lat} \tab Latitude.\cr
\code{lon} \tab Longitude.\cr
\code{geog} \tab Geographic location, derived from \code{lat}
and \code{lon}
}
}
\details{
\code{geog} was generated from \code{lat} and \code{lon} using the
code given in the Example section.
}
\source{
Douglas, A. and Delampady, M. (1990), \emph{Eastern Lake Survey --
Phase I: Documentation for the Data Base and the Derived Data
sets.} Tech Report 160 (SIMS), Dept. Statistics, University of
British Columbia.
}
\references{
Gu, C. and Wahba, G. (1993), Semiparametric analysis of variance
with tensor product thin plate splines. \emph{Journal of the Royal
Statistical Society Ser. B}, \bold{55}, 353--368.
}
\examples{
## Converting latitude and longitude to x-y coordinates
\dontrun{convert <- function(lat, lon) {
lat <- lat/180*pi
lon <- lon/180*pi
m.lat <- (max(lat)+min(lat))/2
m.lon <- (max(lon)+min(lon))/2
x <- cos(m.lat)*sin(m.lon-lon)
y <- sin(lat-m.lat)
cbind(x,y)
}
data(LakeAcidity)
convert(LakeAcidity$lat,LakeAcidity$lon)
## Clean up
rm(LakeAcidity,convert)}
}
\keyword{datasets}