Resolve "Subscriber&processor for landmark external detections"

Closes #478 (closed)

include/core/factor/factor_base.h

@@ -123,6 +123,31 @@ class FactorBase : public NodeBase, public std::enable_shared_from_this<FactorBa
             return topology_;
         }
 
+        std::string getTopologyString() const
+        {
+            switch (topology_)
+            {
+            case TOP_GEOM:
+                return "GEOM";
+                break;
+            case TOP_ABS:
+                return "ABS";
+                break;
+            case TOP_LMK:
+                return "LMK";
+                break;
+            case TOP_LOOP:
+                return "LOOP";
+                break;
+            case TOP_OTHER:
+                return "OTHER";
+                break;
+            default:
+                return "UNDEFINED";
+            }
+        }
+
+
         /** \brief Evaluate the factor given the input parameters and returning the residuals and jacobians
         **/
         virtual bool evaluate(double const* const* _parameters, double* _residuals, double** _jacobians) const = 0;