r.to.rast3 manual: some improvements

git-svn-id: https://svn.osgeo.org/grass/grass/branches/releasebranch_7_0@64890 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.to.rast3/r.to.rast3.html

@@ -1,8 +1,9 @@
 <h2>DESCRIPTION</h2>
 
-Converts 2D raster map(s) into one RASTER3D raster map. 
-If the 2d and 3d region settings are different,
-the 2d resolution will be adjust to the 3d resolution.
+Converts 2D raster map(s) into one raster3D map. It is important to
+properly set the 3D region settings, especially number or layers and
+depth of layers. If the 2D and 3D region settings are different,
+the 2D resolution will be adjusted to the 3D resolution.
 
 <center>
 <img src="r.to.rast3.png" border="0"><br>
@@ -15,30 +16,34 @@ the 2d resolution will be adjust to the 3d resolution.
 
 
 <h2>NOTES</h2>
-Every 2D raster map is copied as one slice to the RASTER3D raster map. Slices
+Every 2D raster map is copied as one slice to the raster3D map. Slices
 are counted from bottom to the top, so the bottom slice has to be number 1. 
 <br><br>
-If fewer 2D raster maps are provided than depths, the last give 2D map is
-used to fill up the  RASTER3D slices to the top.
+If less number of 2D raster maps are provided than defined depths, the
+last given 2D map is used to fill up the remaining raster3D slices to
+the top.
 
 <h2>EXAMPLES</h2>
 
 <h3>EXAMPLE 1</h3>
 
-This example shows how to convert 6 maps into one 3d map with 6 layers.
+This example shows how to convert 6 maps into one 3D map with 6 layers.
 <br>
 
 <div class="code"><pre>
 # Mapset data in Location slovakia3d
+g.region raster=prec_1,prec_2,prec_3,prec_4,prec_5,prec_6 -p
+g.region b=0 t=600 tbres=100 res3=100 -p3
 r.to.rast3 input=prec_1,prec_2,prec_3,prec_4,prec_5,prec_6 output=new_3dmap
 </pre></div>
 
 <h3>EXAMPLE 2</h3>
-This example shows how to convert 3 maps into one 3d map with 6 layers.
+This example shows how to convert 3 maps into one 3D map with 6 layers.
 <br>
 
 <div class="code"><pre>
 # Mapset data in Location slovakia3d
+g.region b=0 t=600 tbres=100 res3=100 -p3
 r.to.rast3 input=prec_1,prec_2,prec_3 output=new_3dmap
 </pre></div>