Changeset 58765

Timestamp:

Jan 22, 2014, 10:58:40 AM (11 years ago)

Author:

wenzeslaus

Message:

r.mapcalc: add note about eval function variables and existing maps

File:

• grass/trunk/raster/r.mapcalc/r.mapcalc.html (modified) (1 diff)

grass/trunk/raster/r.mapcalc/r.mapcalc.html

@@ -580 +580 @@
 This example uses unix-like <tt>&lt;&lt; EOF</tt> syntax to provide
 input to <em>r.mapcalc</em>.
+<p>
+Note that the temporary variables (maps) are not created
+and thus it does not matter whether they exists or not.
+In the example above, if map <tt>elev_200</tt> exists it will not be
+overwritten and no error will be generated.
+The reason is that the name <tt>elev_200</tt> now denotes the temporary
+variable (map) and not the existing map.
+The following parts of the expression will use the temporary <tt>elev_200</tt>
+and the existing <tt>elev_200</tt> will be left intact and will not be used.
+If a user want to use the existing map, the name of the temporary variable
+(map) must be changed.
 
 <h3>Random number generator initialization</h3>