LakeAcid: Water Acidity in Lakes
In gss: General Smoothing Splines

LakeAcidity

R Documentation

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 data frame containing 112 observations on the following variables.

`ph`	Surface ph.
`cal`	Calcium concentration.
`lat`	Latitude.
`lon`	Longitude.
`geog`	Geographic location, derived from `lat` and `lon`

Details

geog was generated from lat and lon using the code given in the Example section.

Source

Douglas, A. and Delampady, M. (1990), 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. Journal of the Royal Statistical Society Ser. B, 55, 353–368.

Examples

## Converting latitude and longitude to x-y coordinates
## Not run: ltln2xy <- function(latlon,latlon0) {
  lat <- latlon[,1]*pi/180; lon <- latlon[,2]*pi/180
  lt0 <- latlon0[1]*pi/180; ln0 <- latlon0[2]*pi/180
  x <- cos(lt0)*sin(lon-ln0); y <- sin(lat-lt0)
  cbind(x,y)
}
data(LakeAcidity)
latlon <- as.matrix(LakeAcidity[,c("lat","lon")])
m.lat <- (min(latlon[,1])+max(latlon[,1]))/2
m.lon <- (min(latlon[,2])+max(latlon[,2]))/2
ltln2xy(latlon,c(m.lat,m.lon))
## Clean up
rm(ltln2xy,LakeAcidity,latlon,m.lat,m.lon)
## End(Not run)

gss documentation built on Oct. 12, 2024, 1:08 a.m.