Add option for the potentially visible value.

Add doc.

Author: abellgithub

apps/gdalalg_raster_viewshed.cpp

@@ -120,6 +120,12 @@ GDALRasterViewshedAlgorithm::GDALRasterViewshedAlgorithm(bool standaloneStep)
         .SetDefault(m_opts.invisibleVal)
         .SetMinValueIncluded(0)
         .SetMaxValueIncluded(255);
+    AddArg("maybe-visible-value", 0,
+           _("Pixel value to set for potentially visible areas"),
+           &m_opts.maybeVisibleVal)
+        .SetDefault(m_opts.maybeVisibleVal)
+        .SetMinValueIncluded(0)
+        .SetMaxValueIncluded(255);
     AddArg("out-of-range-value", 0,
            _("Pixel value to set for the cells that fall outside of the range "
              "specified by the observer location and the maximum distance"),

doc/source/programs/gdal_raster_viewshed.rst

@@ -203,6 +203,17 @@ Program-Specific Options
 
    Pixel value to set for visible areas. (Not supported in cumulative mode) Default: 255
 
+  .. versionadded:: 3.13
+
+.. option:: --sd-filename <value>
+
+   Filename of raster containting standard deviations of the input raster values. The raster
+   always comes from band 1 and the size must match that of the input raster.
+
+.. option:: --maybe-visible-value <value>
+
+   Pixel value to set for visible areas. (Not supported in cumulative mode) Default: 255
+
 
 Standard Options
 ----------------