message: Added a getter to a const pointer.
diff: @@ -58,6 +58,7 @@ class TsdfMap {
  virtual ~TsdfMap() {}
  Layer<TsdfVoxel>* getTsdfLayerPtr() { return tsdf_layer_.get(); }
  + const Layer<TsdfVoxel>* getTsdfLayerConstPtr() const { return tsdf_layer_.get(); }
  const Layer<TsdfVoxel>& getTsdfLayer() const { return *tsdf_layer_; }
  FloatingPoint block_size() const { return block_size_; }
  