\name{Sonar}
\title{Sonar, Mines vs. Rocks}
\usage{data(Sonar)}
\alias{Sonar}
\format{A data frame with 208 observations on 61 variables, all numerical and one (the Class) nominal.}

\description{This is the data set used by Gorman and Sejnowski in their
    study of the classification of sonar signals using a neural network
    [1]. The task is to train a network to discriminate between sonar
    signals bounced off a metal cylinder and those bounced off a roughly
    cylindrical rock.  
    
    Each pattern is a set of 60 numbers in the range 0.0 to 1.0. Each
    number represents the energy within a particular frequency band,
    integrated over a certain period of time. The integration aperture
    for higher frequencies occur later in time, since these frequencies
    are transmitted later during the chirp.
    
    The label associated with each record contains the letter "R" if the
    object is a rock and "M" if it is a mine (metal cylinder). The
    numbers in the labels are in increasing order of aspect angle, but
    they do not encode the angle directly. 
}

\source{
    \itemize{
       	\item Contribution: Terry Sejnowski, Salk Institute and
	University of California, San Deigo.
	\item Development: R. Paul Gorman, Allied-Signal Aerospace
	Technology Center. 
	\item Maintainer: Scott E. Fahlman 
	
    }
    These data have been taken from the UCI Repository Of Machine Learning
    Databases at
    \itemize{
      \item \url{ftp://ftp.ics.uci.edu/pub/machine-learning-databases}
      \item \url{http://www.ics.uci.edu/~mlearn/MLRepository.html}
    }
    and were converted to R format by Evgenia Dimitriadou.
}

\references{
  Gorman, R. P., and Sejnowski, T. J. (1988). "Analysis of Hidden
  Units in a Layered Network Trained to Classify Sonar Targets" in
  Neural Networks, Vol. 1, pp. 75-89.

  Newman, D.J. & Hettich, S. & Blake, C.L. & Merz, C.J. (1998).
  UCI Repository of machine learning databases
  [http://www.ics.uci.edu/~mlearn/MLRepository.html]. Irvine, CA:
  University of California, Department of Information and Computer
  Science.
}
\keyword{datasets}
\examples{
data(Sonar)
summary(Sonar)
}
    

