Merge pull request #1031 from PatrikSylve/class_fallback

Document FALLBACK keyword

Author: geographika

en/mapfile/class.txt

@@ -7,6 +7,8 @@
  CLASS
 *****************************************************************************
 
+:Last Updated: 2025-08-18
+
 .. index:: 
    pair: CLASS; BACKGROUNDCOLOR
    :name: mapfile-class-backgroundcolor
@@ -90,10 +92,21 @@ EXPRESSION [string]
     .. note::
         |RUNSUB|
 
+.. index::
+   pair: CLASS; FALLBACK
+   :name: mapfile-class-fallback
+
+FALLBACK [true|false]
+    Specifies whether the class should act as a fallback class.
+    A fallback class is applied if and only if none of the previously 
+    defined classes has been applied. This is similar in concept to
+    the :ref:`sld` ElseFilter.
+   .. versionadded:: 8.5
+
 .. index::
    pair: CLASS; GROUP
    :name: mapfile-class-group
-    
+
 GROUP [string]
     Allows for grouping of classes.  It is only used when a
     `CLASSGROUP` at the :ref:`LAYER` level is set. If the `CLASSGROUP`

en/ogc/sld.txt

@@ -10,7 +10,7 @@
 :Author: Jeff McKenna
 :Contact: jmckenna at gatewaygeomatics.com
 :Author: Yewondwossen Assefa
-:Last Updated: 2024-06-27
+:Last Updated: 2025-08-18
 
 .. contents::
     :depth: 2
@@ -250,12 +250,12 @@ RasterSymbolizer    Yes       Applies for 8-bit rasters
   For each rule containing a filter, there is a class created with the
   class expression set to reflect that filter. Available filters that
   can be used are Comparison Filters and Logical Filters (see the
-  :ref:`Filter Encoding HowTo <filter_encoding>`).  The ElseFilter
-  parameters are converted into a class in MapServer and placed at the
-  end of the class list with no expression set. They are used to
-  render elements that did not fit into any other classes.
+  :ref:`Filter Encoding HowTo <filter_encoding>`). The ElseFilter
+  parameters are converted into a class without an expression, placed
+  at the end of the class list, and flagged as fallback. They are used
+  to render elements that did not fit into any other classes.
 
-- MinScaleDenomibator and MaxScaleDenominator are translated in minscale and 
+- MinScaleDenominator and MaxScaleDenominator are translated in minscale and 
   maxscale in MapServer.
 
 The following are examples of valid requests using the Filters:
@@ -792,6 +792,8 @@ Other Items Implemented
   - Referencing an SLD file in the LAYER :ref:`STYLEITEM <mapfile-layer-styleitem>`
   - Reading SLD strings when from an attribute defined in the LAYER :ref:`STYLEITEM <mapfile-layer-styleitem>`
 
+- Added the `FALLBACK` keyword in :ref:`CLASS <mapfile-class-fallback>` to support the functionality of `ElseFilter` in SLD.
+
 Issues Found During Implementation
 ==================================