diff --git a/CoordinateSystem/CoordinateSystem.tex b/CoordinateSystem/CoordinateSystem.tex
new file mode 100644
index 000000000..29ec5b173
--- /dev/null
+++ b/CoordinateSystem/CoordinateSystem.tex
@@ -0,0 +1,246 @@
+%
+% `coord.tex' -- describes the coordinate systems and transforms used
+%                by the FG scenery management subsystem
+%
+%  Written by Curtis Olson.  Started July, 1997.
+%
+% $Id$
+
+
+\documentclass[12pt]{article}
+% \usepackage{times}
+% \usepackage{mathptm}
+
+\usepackage{anysize}
+\papersize{11in}{8.5in}
+\marginsize{1in}{1in}{1in}{1in}
+
+\usepackage{epsfig}
+
+\usepackage{setspace}
+\onehalfspacing
+
+\usepackage{url}
+
+
+\begin{document}
+
+
+\title{
+  Flight Gear Internal Scenery Coordinate Systems and
+  Representations.
+}
+
+\author{
+    Curtis L. Olson\\ 
+    (\texttt{curt@me.umn.edu})
+}
+
+\maketitle
+
+\section{Coordinate Systems}
+
+\subsection{Geocentric Coordinates}
+
+Geocentric coordinates are the polar coordinates centered at the
+center of the earth.  Points are defined by the geocentric longitude,
+geocentric latitude, and distance from the \textit{center} of the
+earth.  Note, due to the non-spherical nature of the earth, the
+geocentric latitude is not exactly the same as the traditional
+latitude you would see on a map.
+
+\subsection{Geodetic Coordinates}
+
+Geodetic coordinates are represented by longitude, latitude, and
+elevation above sea level.  These are the coordinates you would read
+off a map, or see on your GPS.  However, the geodetic latitude does
+not precisely correspond to the angle (in polar coordinates) from the
+center of the earth which the geocentric coordinate system reports.
+
+\subsection{Geocentric vs. Geodetic coordinates}
+
+The difference between geodetic and geocentric coordinates is subtle
+and must be understood.  The problem arose because people started
+mapping the earth using latitude and longitude back when they thought
+the Earth was round (or a perfect sphere.)  It's not though.  It is
+more of an ellipse.  
+
+Early map makers defined the standard \textit{geodetic} latitude as
+the angle between the local up vector and the equator.  This is shown
+in figure \ref{fig:geodesy}.  The point $\mathbf{B}$ marks our current
+position.  The line $\mathbf{ABC}$ is tangent to the ellipse at point
+$\mathbf{B}$ and represents the local ``horizontal.''  The line
+$\mathbf{BF}$ represents the local ``up'' vector.  Thus, in
+traditional map maker terms, the current latitude is the angle defined
+by $\angle \mathbf{DBF}$.
+
+However, as you can see from the figure, the line $\mathbf{BF}$ does
+not extend through the center of the earth.  Instead, the line
+$\mathbf{BE}$ extends through the center of the earth.  So in
+\textit{geocentric} coordinates, our latitude would be reported as the
+angle $\angle \mathbf{DBE}$.
+
+\begin{figure}[hbt]
+  \centerline{                   
+      \psfig{file=geodesy.eps}
+  }
+  \caption{Geocentric vs. Geodetic coordinates}
+  \label{fig:geodesy}
+\end{figure}
+
+The LaRCsim flight model operates in geocentric coordinates
+internally, but reports the current position in both coordinate
+systems.
+
+\subsection{World Geodetic System 1984 (WGS 84)}
+
+The world is not a perfect sphere.  WGS-84 defines a standard model
+for dealing with this.  The LaRCsim flight model code already uses the
+WGS-84 standard in its calculations.
+
+For those that are interested here are a couple of URLS for more
+information:
+
+\noindent
+\url{http://acro.harvard.edu/SSA/BGA/wg84figs.html} \\
+\url{http://www.afmc.wpafb.af.mil/organizations/HQ-AFMC/IN/mist/dma/wgs1984.htm}
+\\
+\url{http://www.nima.mil/publications/guides/dtf/datums.html}
+
+To maintain simulation accuracy, the WGS-84 model should be used when
+translating geodetic coordinates (via geocentric coordinates) into the
+FG Cartesian coordinate system.  The code to do this can probably be
+borrowed from the LaRCsim code.  It is located in
+\texttt{ls\_geodesy.c}.
+
+\subsection{Cartesian Coordinates}
+
+Internally, all flight gear scenery is represented using a Cartesian
+coordinate system.  The origin of this coordinate system is the center
+of the earth.  The X axis runs along a line from the center of the
+earth out to the equator at the zero meridian.  The Z axis runs along
+a line between the north and south poles with north being positive.
+The Y axis is parallel to a line running through the center of the
+earth out through the equator somewhere in the Indian Ocean.  Figure
+\ref{fig:coords} shows the orientation of the X, Y, and Z axes in
+relationship to the earth.
+
+\begin{figure}[hbt]
+  \centerline{                   
+      \psfig{file=coord.eps}
+  }
+  \caption{Flight Gear Coordinate System}
+  \label{fig:coords}
+\end{figure}
+
+\newpage
+
+\subsection{Converting between coordinate systems}
+
+Different aspects of the simulation will need to deal with positions
+represented in the various coordinate systems.  Typically map data is
+presented in the geodetic coordinate system.  The LaRCsim code uses
+the geocentric coordinate system.  FG will use a Cartesian coordinate
+system for representing scenery internally.  Potential add on items
+such as GPS's will need to know positions in the geodetic coordinate
+system, etc.
+
+FG will need to be able to convert positions between any of these
+coordinate systems.  LaRCsim comes with code to convert back and forth
+between geodetic and geocentric coordinates.  So, we only need to
+convert between geocentric and cartesian coordinates to complete the
+picture.  Converting from geocentric to cartesian coordinates is done
+by using the following formula:  \\
+$x = cos(lon_\mathit{geocentric}) * cos(lat_\mathit{geocentric}) *
+radius_\mathit{geocentric}$  \\
+$y = sin(lon_\mathit{geocentric}) * cos(lat_\mathit{geocentric}) *
+radius_\mathit{geocentric}$ \\
+$z = sin(lat_\mathit{geocentric}) * radius_\mathit{geocentric}$
+
+So far I haven't needed to convert from the cartesian coordinate
+system back into any of the polar representations so I haven't derived
+that part yet.  However, it should be pretty straightforward.
+
+
+\section{Scenery Representation}
+
+This section is a work in progress.  I am hashing out ideas as I
+write, so please feel free to send me your comments and suggestions.
+
+\subsection{External Scenery Representation}
+
+This section should deal with the external file format(s) that FG can
+use for input.
+
+\subsection{Internal Scenery Representation}
+
+This section describes how FG represents, manipulates, and
+transforms scenery internally.
+
+Internal, all FG scenery is defined using the coordinate system shown
+in figure \ref{fig:coords}.  This means that regardless of the
+external scenery representation, FG will convert all object to it's
+internal coordinate system when it loads the external file.  Note,
+when a default external FG scenery representation is created, its
+representation should probably parallel the internal FG representation
+as close as possible.  This way, most necessary conversions can then
+be done offline in advance.
+
+\subsection{Scenery Partitioning}
+
+For a first stab, scenery will be partitioned along longitude and
+latitude lines.  This will form trapezium shaped chunks.  I'd like to
+shoot for 10km x 10km chunks.  So, as we move towards the poles, the
+width in degrees of these areas will have to increase.  Figure
+\ref{fig:trap} shows an exaggerated scenery area.
+
+\begin{figure}[hbt]
+  \centerline{                   
+      \psfig{file=trap.eps}
+  }
+  \caption{Scenery Partitioning Scheme}
+  \label{fig:trap}
+\end{figure}
+
+\subsection{Reference Points}
+
+Each scenery area will have a reference point at the center of its
+area.  This reference point (for purposes of avoiding floating point
+precision problems) defines the origin of a local coordinate system
+which is oriented the same as the global coordinate system.  The only
+difference is the origin is translated from the center of the earth to
+the center of the individual areas.  Figure \ref{fig:reference}
+demonstrates this.
+
+\begin{figure}[hbt]
+  \centerline{                   
+      \psfig{file=ref.eps}
+  }
+  \caption{Reference Points and Translations}
+  \label{fig:reference}
+\end{figure}
+
+All the objects for a specific scenery area will be defined based on
+this local coordinate system.  For each scenery area we define a
+vector $\vec{\mathbf{a}}$ which represents the distance from the
+center of the earth to the local coordinate system.
+
+
+\subsection{Putting the pieces of scenery together}
+
+To render a scene, the scenery manager will need to load all the
+nearby areas.  Also, we define a vector $\vec{\mathbf{v}}$ which
+represents the distance from the center of the earth to the current
+view point.  Before rendering each scenery area we translate it by
+$\vec{\mathbf{a}} - \vec{\mathbf{v}}$.  This moves all the current
+scenery areas near the origin, while maintaining the relative
+positions and orientations.  All these transformations are inexpensive
+to calculate and can be done easily with standard OpenGL calls.
+
+It is straightforward to calculate the proper view point and up vector
+so that the scenery will appear right side up when it is rendered.
+
+
+
+\end{document}
+
diff --git a/CoordinateSystem/coord.fig b/CoordinateSystem/coord.fig
new file mode 100644
index 000000000..7c33baab4
--- /dev/null
+++ b/CoordinateSystem/coord.fig
@@ -0,0 +1,25 @@
+#FIG 3.2
+Landscape
+Center
+Inches
+Letter 
+100.00
+Single
+0
+1200 2
+5 1 0 1 0 7 0 0 -1 0.000 0 1 0 0 6000.000 2700.000 4200 5100 6000 5700 7800 5100
+5 1 1 1 0 7 0 0 -1 4.000 0 0 0 0 6000.000 7500.000 4200 5100 6000 4500 7800 5100
+1 3 0 1 0 7 0 0 -1 0.000 1 0.0000 6000 5100 1814 1814 6000 5100 7575 6000
+2 1 0 2 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 2.00 120.00 240.00
+	 6000 5100 8400 5100
+2 1 0 2 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 2.00 120.00 240.00
+	 6000 5100 6000 2700
+2 1 0 2 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 2.00 120.00 240.00
+	 6000 5100 6900 4200
+4 0 0 0 0 0 14 0.0000 4 195 1245 5925 2550 Z (North Pole)\001
+4 0 0 0 0 0 14 0.0000 4 195 1485 6975 4125 Y (Indian Ocean)\001
+4 0 0 0 0 0 14 0.0000 4 150 150 8550 5175 X\001
+4 0 0 0 0 0 14 0.0000 4 195 2025 6750 5475 (Zero Meridian, Africa)\001
diff --git a/CoordinateSystem/geodesy.fig b/CoordinateSystem/geodesy.fig
new file mode 100644
index 000000000..d70a5cb51
--- /dev/null
+++ b/CoordinateSystem/geodesy.fig
@@ -0,0 +1,43 @@
+#FIG 3.2
+Landscape
+Center
+Inches
+Letter 
+100.00
+Single
+0
+1200 2
+1 3 2 1 0 7 0 0 -1 3.000 1 0.0000 6300 4800 1800 1800 6300 4800 8100 4800
+1 1 0 2 0 7 0 0 -1 0.000 1 0.0000 6300 4800 2025 1500 6300 4800 8325 3300
+1 3 0 1 0 0 0 0 20 0.000 1 0.0000 6300 4800 44 44 6300 4800 6344 4795
+2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 1.00 60.00 120.00
+	 7500 3600 8400 2700
+2 1 1 1 0 7 0 0 -1 4.000 0 0 -1 0 0 2
+	 6300 4800 7500 3600
+2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 1.00 60.00 120.00
+	 7500 3600 8700 3600
+2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 1.00 60.00 120.00
+	 7500 3600 8100 2400
+2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 1 2
+	2 1 1.00 60.00 120.00
+	2 1 1.00 60.00 120.00
+	 8700 4200 6000 2850
+2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 1.00 60.00 120.00
+	 5625 4125 5400 3225
+2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 1.00 60.00 120.00
+	 6000 5475 6300 6300
+2 1 1 1 0 7 0 0 -1 4.000 0 0 -1 0 0 2
+	 7500 3600 6750 5100
+4 0 0 0 0 0 14 0.0000 4 150 165 8550 4425 A\001
+4 0 0 0 0 0 14 0.0000 4 150 150 5775 2925 C\001
+4 0 0 0 0 0 14 0.0000 4 150 150 8550 3825 D\001
+4 0 0 0 0 0 14 0.0000 4 150 135 8325 3075 E\001
+4 0 0 0 0 0 14 0.0000 4 150 120 7800 2625 F\001
+4 0 0 0 0 0 12 0.0000 4 180 1125 5100 4350 Perfect Sphere\001
+4 0 0 0 0 0 12 0.0000 4 180 1980 5100 5400 True Earth ellipsoid shape\001
+4 0 0 0 0 0 14 0.0000 4 150 135 7500 3900 B\001
diff --git a/CoordinateSystem/old-coord.fig b/CoordinateSystem/old-coord.fig
new file mode 100644
index 000000000..8de4472ce
--- /dev/null
+++ b/CoordinateSystem/old-coord.fig
@@ -0,0 +1,27 @@
+#FIG 3.2
+Landscape
+Center
+Inches
+Letter 
+100.00
+Single
+0
+1200 2
+5 1 0 1 0 7 0 0 -1 0.000 0 1 0 0 8962.500 6000.000 3600 5100 3525 6000 3600 6900
+5 1 0 1 0 7 0 0 -1 0.000 0 1 0 0 10762.500 6000.000 5400 5100 5325 6000 5400 6900
+5 1 0 1 0 7 0 0 -1 0.000 0 1 0 0 4500.000 -262.500 3600 5100 4500 5175 5400 5100
+5 1 0 1 0 7 0 0 -1 0.000 0 0 0 0 4500.000 1537.500 5400 6900 4500 6975 3600 6900
+5 1 2 1 0 7 0 0 -1 3.000 0 1 0 0 9825.000 6075.000 4500 5175 4425 6000 4500 6975
+5 1 2 1 0 7 0 0 -1 3.000 0 0 0 0 4425.000 637.500 5325 6000 4425 6075 3525 6000
+2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 1.00 60.00 120.00
+	 6000 5175 4425 6075
+2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 1.00 60.00 120.00
+	 6000 5175 8550 5175
+2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 1.00 60.00 120.00
+	 6000 5175 6000 2625
+4 0 0 0 0 0 18 0.0000 4 195 180 8475 5475 X\001
+4 0 0 0 0 0 18 0.0000 4 195 180 5700 2700 Y\001
+4 0 0 0 0 0 18 0.0000 4 195 180 4500 5850 Z\001
diff --git a/CoordinateSystem/ref.fig b/CoordinateSystem/ref.fig
new file mode 100644
index 000000000..cc347e286
--- /dev/null
+++ b/CoordinateSystem/ref.fig
@@ -0,0 +1,47 @@
+#FIG 3.2
+Landscape
+Center
+Inches
+Letter 
+100.00
+Single
+0
+1200 2
+5 1 0 1 0 7 0 0 -1 0.000 0 1 0 0 6900.000 3304.688 5100 5700 6975 6300 8700 5700
+5 1 1 1 0 7 0 0 -1 4.000 0 0 0 0 6900.000 8100.000 5100 5700 6900 5100 8700 5700
+5 1 0 1 0 7 0 0 -1 4.000 0 0 0 0 6900.000 5175.000 5925 5100 6075 4650 6375 4350
+5 1 0 1 0 7 0 0 -1 4.000 0 0 0 0 8887.500 5062.500 6600 5325 6600 4800 6675 4425
+5 1 0 1 0 7 0 0 -1 4.000 0 1 0 0 6675.000 3975.000 5925 5100 6225 5250 6600 5325
+5 1 0 1 0 7 0 0 -1 4.000 0 1 0 0 6600.000 4087.500 6375 4350 6525 4425 6675 4425
+1 3 0 1 0 7 0 0 -1 0.000 1 0.0000 6900 5700 1802 1802 6900 5700 8700 5775
+2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 1.00 60.00 120.00
+	 6300 4800 6300 3600
+2 1 0 2 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 2.00 120.00 240.00
+	 6900 5700 9300 5700
+2 1 0 2 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 2.00 120.00 240.00
+	 6900 5700 7800 4800
+2 1 0 2 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 2.00 120.00 240.00
+	 6900 5700 6900 3300
+2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 1.00 60.00 120.00
+	 6300 4800 7200 4800
+2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	2 1 1.00 60.00 120.00
+	 6300 4800 6750 4350
+2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	0 0 1.00 60.00 120.00
+	 6900 5700 6300 4800
+2 1 0 1 0 7 0 0 -1 0.000 0 0 -1 1 0 2
+	0 0 1.00 60.00 120.00
+	 6075 4950 6300 4950
+4 0 0 0 0 0 14 0.0000 4 150 120 6825 3150 Z\001
+4 0 0 0 0 0 14 0.0000 4 150 135 7875 4800 Y\001
+4 0 0 0 0 0 14 0.0000 4 150 150 9450 5775 X\001
+4 0 0 0 0 0 12 0.0000 4 135 135 7275 4875 X\001
+4 0 0 0 0 0 12 0.0000 4 135 135 6675 4275 Y\001
+4 0 0 0 0 0 12 0.0000 4 135 120 6300 3525 Z\001
+4 0 0 0 0 0 12 0.0000 4 90 90 6150 5100 a\001
diff --git a/CoordinateSystem/trap.fig b/CoordinateSystem/trap.fig
new file mode 100644
index 000000000..546c94a80
--- /dev/null
+++ b/CoordinateSystem/trap.fig
@@ -0,0 +1,16 @@
+#FIG 3.2
+Landscape
+Center
+Inches
+Letter 
+100.00
+Single
+0
+1200 2
+5 1 0 1 0 7 0 0 -1 0.000 0 1 0 0 6900.000 3304.688 5100 5700 6975 6300 8700 5700
+5 1 1 1 0 7 0 0 -1 4.000 0 0 0 0 6900.000 8100.000 5100 5700 6900 5100 8700 5700
+5 1 0 1 0 7 0 0 -1 4.000 0 0 0 0 6900.000 5175.000 5925 5100 6075 4650 6375 4350
+5 1 0 1 0 7 0 0 -1 4.000 0 0 0 0 8887.500 5062.500 6600 5325 6600 4800 6675 4425
+5 1 0 1 0 7 0 0 -1 4.000 0 1 0 0 6675.000 3975.000 5925 5100 6225 5250 6600 5325
+5 1 0 1 0 7 0 0 -1 4.000 0 1 0 0 6600.000 4087.500 6375 4350 6525 4425 6675 4425
+1 3 0 1 0 7 0 0 -1 0.000 1 0.0000 6900 5700 1802 1802 6900 5700 8700 5775