message: Added getter for const ptr.
diff: @@ -51,6 +51,10 @@ class EsdfMap {
  virtual ~EsdfMap() {}
  Layer<EsdfVoxel>* getEsdfLayerPtr() { return esdf_layer_.get(); }
  + const Layer<EsdfVoxel>* getEsdfLayerConstPtr() const {
  + return esdf_layer_.get();
  + }
  +
  const Layer<EsdfVoxel>& getEsdfLayer() const { return *esdf_layer_; }
  FloatingPoint block_size() const { return block_size_; }
  