diff --git a/doc/groups.dox b/doc/groups.dox
--- a/doc/groups.dox
+++ b/doc/groups.dox
@@ -226,14 +226,6 @@
 */
 
 /**
-@defgroup matrices Matrices
-@ingroup datas
-\brief Two dimensional data storages implemented in LEMON.
-
-This group contains two dimensional data storages implemented in LEMON.
-*/
-
-/**
 @defgroup paths Path Structures
 @ingroup datas
 \brief %Path structures implemented in LEMON.
@@ -259,6 +251,28 @@
 */
 
 /**
+@defgroup geomdat Geometric Data Structures
+@ingroup auxdat
+\brief Geometric data structures implemented in LEMON.
+
+This group contains geometric data structures implemented in LEMON.
+
+ - \ref lemon::dim2::Point "dim2::Point" implements a two dimensional
+   vector with the usual operations.
+ - \ref lemon::dim2::Box "dim2::Box" can be used to determine the
+   rectangular bounding box of a set of \ref lemon::dim2::Point
+   "dim2::Point"'s.
+*/
+
+/**
+@defgroup matrices Matrices
+@ingroup auxdat
+\brief Two dimensional data storages implemented in LEMON.
+
+This group contains two dimensional data storages implemented in LEMON.
+*/
+
+/**
 @defgroup algs Algorithms
 \brief This group contains the several algorithms
 implemented in LEMON.
@@ -298,6 +312,15 @@
 */
 
 /**
+@defgroup spantree Minimum Spanning Tree Algorithms
+@ingroup algs
+\brief Algorithms for finding minimum cost spanning trees and arborescences.
+
+This group contains the algorithms for finding minimum cost spanning
+trees and arborescences.
+*/
+
+/**
 @defgroup max_flow Maximum Flow Algorithms
 @ingroup algs
 \brief Algorithms for finding maximum flows.
@@ -391,30 +414,6 @@
 */
 
 /**
-@defgroup graph_properties Connectivity and Other Graph Properties
-@ingroup algs
-\brief Algorithms for discovering the graph properties
-
-This group contains the algorithms for discovering the graph properties
-like connectivity, bipartiteness, euler property, simplicity etc.
-
-\image html connected_components.png
-\image latex connected_components.eps "Connected components" width=\textwidth
-*/
-
-/**
-@defgroup planar Planarity Embedding and Drawing
-@ingroup algs
-\brief Algorithms for planarity checking, embedding and drawing
-
-This group contains the algorithms for planarity checking,
-embedding and drawing.
-
-\image html planar.png
-\image latex planar.eps "Plane graph" width=\textwidth
-*/
-
-/**
 @defgroup matching Matching Algorithms
 @ingroup algs
 \brief Algorithms for finding matchings in graphs and bipartite graphs.
@@ -455,12 +454,36 @@
 */
 
 /**
-@defgroup spantree Minimum Spanning Tree Algorithms
+@defgroup graph_properties Connectivity and Other Graph Properties
 @ingroup algs
-\brief Algorithms for finding minimum cost spanning trees and arborescences.
+\brief Algorithms for discovering the graph properties
 
-This group contains the algorithms for finding minimum cost spanning
-trees and arborescences.
+This group contains the algorithms for discovering the graph properties
+like connectivity, bipartiteness, euler property, simplicity etc.
+
+\image html connected_components.png
+\image latex connected_components.eps "Connected components" width=\textwidth
+*/
+
+/**
+@defgroup planar Planarity Embedding and Drawing
+@ingroup algs
+\brief Algorithms for planarity checking, embedding and drawing
+
+This group contains the algorithms for planarity checking,
+embedding and drawing.
+
+\image html planar.png
+\image latex planar.eps "Plane graph" width=\textwidth
+*/
+
+/**
+@defgroup approx Approximation Algorithms
+@ingroup algs
+\brief Approximation algorithms.
+
+This group contains the approximation and heuristic algorithms
+implemented in LEMON.
 */
 
 /**
@@ -473,15 +496,6 @@
 */
 
 /**
-@defgroup approx Approximation Algorithms
-@ingroup algs
-\brief Approximation algorithms.
-
-This group contains the approximation and heuristic algorithms
-implemented in LEMON.
-*/
-
-/**
 @defgroup gen_opt_group General Optimization Tools
 \brief This group contains some general optimization frameworks
 implemented in LEMON.
@@ -587,7 +601,7 @@
 */
 
 /**
-@defgroup dimacs_group DIMACS format
+@defgroup dimacs_group DIMACS Format
 @ingroup io_group
 \brief Read and write files in DIMACS format
 
@@ -649,6 +663,15 @@
 */
 
 /**
+@defgroup tools Standalone Utility Applications
+
+Some utility applications are listed here.
+
+The standard compilation procedure (<tt>./configure;make</tt>) will compile
+them, as well.
+*/
+
+/**
 \anchor demoprograms
 
 @defgroup demos Demo Programs
@@ -660,13 +683,4 @@
 <tt>make check</tt> commands.
 */
 
-/**
-@defgroup tools Standalone Utility Applications
-
-Some utility applications are listed here.
-
-The standard compilation procedure (<tt>./configure;make</tt>) will compile
-them, as well.
-*/
-
 }