% fields, Tools for spatial data
% Copyright 2004-2011, Institute for Mathematics Applied Geosciences
% University Corporation for Atmospheric Research
% Licensed under the GPL -- www.gpl.org/licenses/gpl.html

\name{ozone2}
\alias{ozone2}
\title{
  Daily 8-hour ozone averages for sites in the Midwest
}
\description{
The response is 8-hour average (surface) ozone ( from 9AM-4PM) measured in
parts per billion (PPB) for 153 sites in the midwestern US over the period
June 3,1987 through August 31, 1987, 89 days. This season of high 
ozone corresponds with a large modeling experiment using the EPA Regional
Oxidant Model.
}
\usage{
data(ozone2)
}
\format{
The data list has components:
<s-args>
<s-arg name="y">
a 89X153 matrix of ozone values. Rows are days and columns are the 
sites. 
</s-arg>
</s-arg name="lon.lat"> 
Site locations in longitude and latitude as a 153X2 table
</s-arg>
<s-arg name="chicago.subset">
Logical vector indicating stations that form teh smaller 
Chicagoland subset. (see FIELDS ozone data set)
</s-arg>
</s-args>
<s-section name="Reference">
Nychka, D., Cox, L., Piegorsch, W. (1998) Case Studies in Environmental 
Statistics Lecture Notes in Statistics, Springer
Verlag, New York 
}
\examples{
data( ozone2)

# pairwise correlation among all stations
# ( See cover.design to continue this example)
cor.mat<- cor( ozone2$y, use="pairwise")

#raw data image for day number 16 
good<- !is.na( ozone2$y[16,])
out<- as.image( ozone2$y[16,good], x=ozone2$lon.lat[good,])
image.plot( out)
}
\keyword{datasets}
% docclass is data
% Converted by Sd2Rd version 1.21.