Index: apps/gdaldem.cpp
===================================================================
--- apps/gdaldem.cpp	(révision 16938)
+++ apps/gdaldem.cpp	(copie de travail)
@@ -3,12 +3,16 @@
  *
  * Project:  GDAL DEM Utilities
  * Purpose:  
- * Author:   Matthew Perry, perrygeo at gmail.com
+ * Authors:  Matthew Perry, perrygeo at gmail.com
  *           Even Rouault, even dot rouault at mines dash paris dot org
  *
  ******************************************************************************
  * Copyright (c) 2006, 2009 Matthew Perry 
  * Copyright (c) 2009 Even Rouault
+ * Copyright (c) Michael Shapiro, U.S.Army Construction Engineering Research Laboratory
+ * Copyright (c) Olga Waupotitsch, U.S.Army Construction Engineering Research Laboratory
+ * Copyright (c) Marjorie Larson, U.S.Army Construction Engineering Research Laboratory
+ * Copyright (c) Jim Westervelt, U.S. Army Construction Engineering Research Laboratory
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -27,9 +31,31 @@
  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  * DEALINGS IN THE SOFTWARE.
+ ****************************************************************************
+ *
+ * Slope and aspect calculations based on original method for GRASS GIS 4.1
+ * by Michael Shapiro, U.S.Army Construction Engineering Research Laboratory
+ *    Olga Waupotitsch, U.S.Army Construction Engineering Research Laboratory
+ *    Marjorie Larson, U.S.Army Construction Engineering Research Laboratory
+ * as found in GRASS's r.slope.aspect module.
+ *
+ * Horn's formula is used to find the first order derivatives in x and y directions
+ * for slope and aspect calculations: Horn, B. K. P. (1981).
+ * "Hill Shading and the Reflectance Map", Proceedings of the IEEE, 69(1):14-47. 
+ *
+ * Other reference :
+ * Burrough, P.A. and McDonell, R.A., 1998. Principles of Geographical Information
+ * Systems. p. 190.
+ *
+ * Shaded relief based on original method for GRASS GIS 4.1 by Jim Westervelt,
+ * U.S. Army Construction Engineering Research Laboratory
+ * as found in GRASS's r.shaded.relief (formerly shade.rel.sh) module.
+ * ref: "r.mapcalc: An Algebra for GIS and Image Processing",
+ * by Michael Shapiro and Jim Westervelt, U.S. Army Construction Engineering
+ * Research Laboratory (March/1991)
+ *
  ****************************************************************************/
 
-
 #include <stdlib.h>
 #include <math.h>
 
Index: PROVENANCE.TXT
===================================================================
--- PROVENANCE.TXT	(révision 16938)
+++ PROVENANCE.TXT	(copie de travail)
@@ -137,6 +137,10 @@
 * gdal_contour.cpp: copyright held by ACT. 
 * gdaltindex.cpp: copyright held by DM Solutions.
 * gdalwarp.cpp, gdalwarpsimple.cpp: copyright held by i-cubed. 
+* gdaldem.cpp: copyright held by Matthew Perry, Even Rouault, Michael Shapiro (US Army CERL),
+               Olga Waupotitsch (US Army CERL), Marjorie Larson (US Army CERL), Jim Westervelt (US Army CERL).
+               Derived from modules of GRASS 4.1 (public domain), properly noted in the headers.
+               See http://trac.osgeo.org/gdal/ticket/2975
 
 === gdal/debian === 
 
Index: apps/gdal_utilities.dox
===================================================================
--- apps/gdal_utilities.dox	(révision 16938)
+++ apps/gdal_utilities.dox	(copie de travail)
@@ -1668,8 +1668,21 @@
 \endverbatim
 
 
-\if man
 \section gdaldem_author AUTHORS
 Matthew Perry <perrygeo@gmail.com>, Even Rouault <even.rouault@mines-paris.org>
-\endif
+
+Derived from code by Michael Shapiro, Olga Waupotitsch, Marjorie Larson, Jim Westervelt :
+U.S. Army CERL, 1993. GRASS 4.1 Reference Manual. U.S. Army Corps of Engineers,
+Construction Engineering Research Laboratories, Champaign, Illinois, 1-425. 
+
+\section gdaldem_seealso See also
+
+Documentation of related GRASS utilities :
+
+http://grass.osgeo.org/grass64/manuals/html64_user/r.slope.aspect.html
+
+http://grass.osgeo.org/grass64/manuals/html64_user/r.shaded.relief.html
+
+http://grass.osgeo.org/grass64/manuals/html64_user/r.colors.html
+
 */
\ No newline at end of file