doc: Add example rating curve.

* doc/fullswof-utils.texi (Theory): Add figure.
* images/rating_curve.png: New file.

2 files changed, 17 insertions, 0 deletions

diff --git a/doc/fullswof-utils.texi b/doc/fullswof-utils.texi
index b98e587..d00e999 100644
--- a/doc/fullswof-utils.texi
+++ b/doc/fullswof-utils.texi
@@ -438,6 +438,23 @@ are calculated.  From these values the hydraulic radius is calculated,
 allowing the conveyance to be determined.  Finally, the discharge is
 calculated from the conveyance.
 
+@float Figure,ratingCurve
+  @image{./images/rating_curve}
+  @caption{Rating curve for the right hand panel of the top boundary.}
+@end float
+
+An example rating curve is shown in @ref{ratingCurve}.  The data for
+this curve was generated from the topography and boundary definition
+file provided in the @file{demo} directory.
+
+Together, the rating curves establish the connection between water level
+and discharge at the boundary.  The @emph{makeBoundary} program
+identifies the panels that are filled and the panel that is part-filled.
+The discharge in the part-filled panel is set so that the sum of the
+discharge values is equal to the target flow.  The last step is to
+interpolate the water level from the rating curve of the part-filled
+panel.
+
 @node Demos, GNU Free Documentation License, Boundary Definition File, Top
 @comment  node-name,  next,  previous,  up
 @chapter Demos
diff --git a/images/rating_curve.png b/images/rating_curve.png
new file mode 100644
index 0000000..a13e96f
--- /dev/null
+++ b/images/rating_curve.png