diff --git a/owlps-positioning/src/stock.cc b/owlps-positioning/src/stock.cc
index e14002a..ce4a12e 100644
--- a/owlps-positioning/src/stock.cc
+++ b/owlps-positioning/src/stock.cc
@@ -300,6 +300,21 @@ double Stock::ap_matrix_get_ss(const std::string &mac_transmitter,
 }
 
 
+/**
+ * @returns \em true if \em coord are the coordinates of an existing
+ * AP, \em false if not.
+ */
+bool Stock::is_ap_coordinate(const Point3D &coord)
+{
+  for (unordered_map<string, AccessPoint>::const_iterator ap =
+         aps.begin() ; ap != aps.end() ; ++ap)
+    if (ap->second.get_coordinates() == coord)
+      return true ;
+
+  return false ;
+}
+
+
 
 /* *** ReferencePoint operations *** */
 
diff --git a/owlps-positioning/src/stock.hh b/owlps-positioning/src/stock.hh
index dd8cb91..fb8a50a 100644
--- a/owlps-positioning/src/stock.hh
+++ b/owlps-positioning/src/stock.hh
@@ -108,8 +108,12 @@ public:
   static AccessPoint& getw_ap(const std::string &mac) ;
   /// Updates the friis indexes of all the APs
   static void update_all_friis_indexes(void) ;
+  /// \brief Returns the signal strenth received by an AP mac_receiver
+  /// from an AP mac_transmitter
   static double ap_matrix_get_ss(const std::string &mac_transmitter,
                                  const std::string &mac_receiver) ;
+  /// Checks if a Point3D is the coordinate of an existing AP
+  static bool is_ap_coordinate(const Point3D &coord) ;
   //@}
 
   /** @name ReferencePoint operations */