\chapter{Data preparation}
\section{Terrain Data Projection}
% UTM to lat. long.
% lat. long. to UTN
% is computed by using grass 4.1 
% parameters:

\section{Recover Missing DEM Values}
%  Fixes holes.
%
%
\begin{figure}
\begin{center}
\begin{picture}(468,468)
\psfig{figure=albany_dem100_holes.ps,width=468pt,height=468pt}
\end{picture}
\end{center}
\caption{Original Digital Elevation Model with holes.\label{DEM_holes}}
\end{figure}

\begin{figure}
\begin{center}
\begin{picture}(468,468)
\psfig{figure=albany_dem100_holes_fixed.ps,width=468pt,height=468pt}
\end{picture}
\end{center}
\caption{Digital Elevation Model with holes removed.\label{DEM_holes_fixed}}
\end{figure}

\begin{figure}
\begin{center}
\begin{picture}(468,98)
\psfig{figure=holes_compare1.ps,width=468pt,height=98pt}
\end{picture}
\end{center}
\caption{A magnify view of the same region with and without holes.
\label{DEM_compare1}}
\end{figure}

\begin{figure}
\begin{center}
\begin{picture}(468,468)
\psfig{figure=holes_compare2.ps,width=468pt,height=468pt}
\end{picture}
\end{center}
\caption{A magnify view of the larges area with the larges hole before and
after the fix.\label{DEM_compare2}}
\end{figure}

