diff --git a/owlps-positioner/Makefile b/owlps-positioner/Makefile
index 85eaccc..59d5673 100644
--- a/owlps-positioner/Makefile
+++ b/owlps-positioner/Makefile
@@ -193,6 +193,7 @@ $(OBJ_DIR)/calibrationrequest.o: \
 	$(OBJ_DIR)/direction.o
 $(OBJ_DIR)/result.o: \
 	$(OBJ_DIR)/stock.o \
+	$(OBJ_DIR)/configuration.o \
 	$(OBJ_DIR)/area.o \
 	$(OBJ_DIR)/request.o
 $(OBJ_DIR)/resultlist.o: \
diff --git a/owlps-positioner/cfg/owlps-positioner.conf b/owlps-positioner/cfg/owlps-positioner.conf
index e3b79b9..3b653d8 100644
--- a/owlps-positioner/cfg/owlps-positioner.conf
+++ b/owlps-positioner/cfg/owlps-positioner.conf
@@ -206,6 +206,12 @@ csv-file = /tmp/owlps-positioner.log
 [output]
 # The following options are related to the output of the results.
 
+# Compute the euclidean distance error in two dimensions instead of
+# three dimensions. This can be useful when doing experiments on only
+# one floor.
+# The default is false, i.e. the error is computed in 3D.
+#2d-error = false
+
 # This is the default output if none is specified.
 #medium = Terminal
 
diff --git a/owlps-positioner/src/result.cc b/owlps-positioner/src/result.cc
index 1dfdd8d..769a530 100644
--- a/owlps-positioner/src/result.cc
+++ b/owlps-positioner/src/result.cc
@@ -9,6 +9,7 @@
 #include "request.hh"
 #include "area.hh"
 #include "stock.hh"
+#include "configuration.hh"
 
 #include <sstream>
 
@@ -49,7 +50,10 @@ string Result::in_which_area() const
 
 void Result::compute_error(const Point3D &real_position)
 {
-  error = position.distance(real_position) ;
+  if (Configuration::bool_value("output.2d-error"))
+    error = position.distance_2d(real_position) ;
+  else
+    error = position.distance(real_position) ;
 }
 
 
diff --git a/owlps-positioner/src/userinterface.cc b/owlps-positioner/src/userinterface.cc
index d54c68b..20bcbb5 100644
--- a/owlps-positioner/src/userinterface.cc
+++ b/owlps-positioner/src/userinterface.cc
@@ -308,6 +308,10 @@ void UserInterface::fill_output_options()
   po::options_description options("Output options") ;
 
   options.add_options()
+  ("output.2d-error",
+   po::value<bool>()->default_value(false),
+   "Compute the distance error in two dimensions instead of three"
+   " dimensions.")
   ("output.medium,O",
    po::value< vector<string> >()->composing(),
    "Medium to which the results will be written. You can specify"