[mapserver-commits] r11113 - trunk/docs/en/mapfile

[svn at osgeo.org]

Author: tamas
Date: 2011-03-08 08:32:25 -0800 (Tue, 08 Mar 2011)
New Revision: 11113

Added:
   trunk/docs/en/mapfile/cluster.txt
Modified:
   trunk/docs/en/mapfile/index.txt
   trunk/docs/en/mapfile/layer.txt
Log:
Adding documentation for the clustering option (#3700)

Added: trunk/docs/en/mapfile/cluster.txt
===================================================================
--- trunk/docs/en/mapfile/cluster.txt	                        (rev 0)
+++ trunk/docs/en/mapfile/cluster.txt	2011-03-08 16:32:25 UTC (rev 11113)
@@ -0,0 +1,45 @@
+.. _cluster:
+
+*****************************************************************************
+ CLUSTER
+*****************************************************************************
+
+The CLUSTER configuration option provides to combine multiple features from 
+the layer into single (aggregated) features based on their relative positions.
+Supported only for POINT layers.
+
+The clustered layer itself provides the following aggregate attributes: 
+
+1) Cluster:FeatureCount - count of the features in the clustered shape 
+2) Cluster:Group - The group value of the cluster (to which the group expression is evaluated)
+
+These attributes (in addition to the attributes provided by the original data source) can be used to configure 
+the labels of the features and can also be used in expressions. 
+The ITEMS processing option can be used to specify a subset of the attributes from the original 
+layer in the query operations according to the user's preference.
+
+If we retrieve the original attributes then the cluster layer provider will provide only those values which
+are equal for each shapes contained by the cluster. The other values are set to "Cluster:Empty".
+  
+.. seealso::       
+    :ref:`rfc69`
+
+MAXDISTANCE [double]
+    Specifies the distance of the search region (rectangle or ellipse) in pixel positions.
+  
+REGION [string]
+    Defines the search region around a feature in which the neighbouring features are negotiated.
+    Can be 'rectangle' or 'ellipse'.
+    
+:ref:`GROUP <expressions>` [string]
+    This expression evaluates to a string and only the features that have the
+    same group value are negotiated. This parameter can be omitted. The evaluated group value is 
+    available in the 'Cluster:Group' feature attribute.
+    
+:ref:`FILTER <expressions>` [string]
+    We can define the FILTER expression filter some of the features from the final output.
+    This expression evaluates to a boolean value and if this value is false 
+    the corresponding shape is filtered out. 
+    This expression is evaluated after the the feature negotiation is completed, therefore
+    the 'Cluster:FeatureCount' parameter can also be used, which provides the option
+    to filter the shapes having too many or to few neighbors within the search region.

Modified: trunk/docs/en/mapfile/index.txt
===================================================================
--- trunk/docs/en/mapfile/index.txt	2011-03-08 15:34:23 UTC (rev 11112)
+++ trunk/docs/en/mapfile/index.txt	2011-03-08 16:32:25 UTC (rev 11113)
@@ -31,6 +31,7 @@
 
    symbology/construction
    class
+   cluster
    labelencoding   
    expressions
    feature

Modified: trunk/docs/en/mapfile/layer.txt
===================================================================
--- trunk/docs/en/mapfile/layer.txt	2011-03-08 15:34:23 UTC (rev 11112)
+++ trunk/docs/en/mapfile/layer.txt	2011-03-08 16:32:25 UTC (rev 11113)
@@ -26,6 +26,16 @@
     The :ref:`CLASS` object's GROUP parameter must be used in combination with
     CLASSGROUP.
     
+:ref:`CLUSTER`
+    Signals the start of a :ref:`CLUSTER` object.
+
+    The CLUSTER configuration option provides to combine multiple features from 
+    the layer into single (aggregated) features based on their relative positions.
+    Supported only for POINT layers.
+    
+    .. seealso::       
+        :ref:`rfc69`
+    
 CONNECTION [string]
     Database connection string to retrieve remote data.