Index: trunk/doc/pslib/psLibSDRS.tex
===================================================================
--- trunk/doc/pslib/psLibSDRS.tex	(revision 7991)
+++ trunk/doc/pslib/psLibSDRS.tex	(revision 8000)
@@ -1,3 +1,3 @@
-%%% $Id: psLibSDRS.tex,v 1.424 2006-07-27 03:52:15 price Exp $
+%%% $Id: psLibSDRS.tex,v 1.425 2006-07-28 00:49:31 price Exp $
 \documentclass[panstarrs,spec]{panstarrs}
 
@@ -4810,4 +4810,18 @@
 \code{psStatsToString} shall translate in the reverse direction.
 
+Since the statistics functions are often used with only a single
+statistic desired (e.g., in image combination, where the output pixel
+is a statistic value), we provide functions to assist with this:
+\begin{prototype}
+psStatsOptions psStatsSingleOption(psStatsOptions option);
+double psStatsGetValue(const psStats *stats, psStatsOptions option);
+\end{prototype}
+\code{psStatsSingleOption} shall return the single statistics option
+that is set in the input \code{option}, or zero in the event that
+multiple or no options are set.  \code{psStatsGetValue} shall return
+the value of the particular statistic in the \code{stats} structure
+that corresponds to the supplied single statistics \code{option}; the
+function shall return \code{NAN} in the event of an error.
+
 \begin{prototype}
 long psVectorCountPixelMask (psVector *mask, psMaskType value);