\HeaderA{is.projected}{Sets or retrieves projection attributes on classes extending
SpatialData}{is.projected}
\aliasA{proj4string}{is.projected}{proj4string}
\aliasA{proj4string<\Rdash}{is.projected}{proj4string<.Rdash.}
\keyword{spatial}{is.projected}
\begin{Description}\relax
Sets or retrieves projection attributes on classes extending
SpatialData
\end{Description}
\begin{Usage}
\begin{verbatim}
is.projected(sd)
proj4string(sd)
proj4string(sd) <- value
\end{verbatim}
\end{Usage}
\begin{Arguments}
\begin{ldescription}
\item[\code{sd}] An object of class or extending \LinkA{Spatial-class}{Spatial.Rdash.class}
\item[\code{value}] character string, indicating a valid proj4 string 
\end{ldescription}
\end{Arguments}
\begin{Details}\relax
proj4 strings are not operative yet
\end{Details}
\begin{Value}
\code{is.projected} returns a logical; \code{proj4string}
returns a character vector of length 1; \code{spatial.dimension}
returns the number of spatial dimensions (2 or 3).
\end{Value}
\begin{Author}\relax
Edzer J. Pebesma, \email{e.pebesma@geo.uu.nl}
\end{Author}
\begin{SeeAlso}\relax
\LinkA{CRS}{CRS}
\end{SeeAlso}
\begin{Examples}
\begin{ExampleCode}

\end{ExampleCode}
\end{Examples}

